Sound characteristics of audio equipment
In the audio market, we can find many related introductions of various equipments. Usually, they will describe the various
characteristics in the equipment from the positive, and rarely explain the negative effects behind the characteristics. However,
these negative factors control the quality on the music playback function. To get the sound effects you expect, you need to
fully understand the equipment. In the following content, we will technically analyze what are the deficiencies in the equipment,
what impact will it bring to the functional quality, and what sound characteristics will appear from this.
We do not
intend to evaluate the quality of the equipment, nor do we intend to impeach the defects of the equipment. Here is just to
introduce the sound characteristics of these devices from the perspective of principles, so that when you use these devices,
you can give full play to their strengths and avoid weaknesses. If necessary, you can quickly determine the location of the
sound effect based on these characteristics. It must be known that, like everything else, audio equipment is not absolutely
good or bad. In daily music appreciation, as long as the equipment can meet the sound effects you like, it is a good equipment
for your sound system.
Everything in the world should have an explanation, and the sound system is no exception. Audio
equipment is a product of electronic technology, and its various phenomena must conform to physical principles and should
be explained technically. In principle, all types of equipment have sound characteristics produced by their physical characteristics.
Although each device of the same device has its own sound personality, the common characteristics of their device types will
In the following, we will use the term micro-dynamics. Micro dynamics is the ratio of two voltage (or
sound pressure) values in a time interval. In some cases, it is equivalent to what audio enthusiasts call micro-dynamics.
The only difference is the length of the time interval. Generally, the minimum time interval for the human ear to confirm
the existence of two sound pressure intensities (or there are two sounds) from the sound is 0.1 second. The micro dynamics
we are referring to here include very short time intervals and extend to a range that can be distinguished by the human ear.
We will also use the term "Sound State" in the following description. Sound State——The
emotional state of the sound. Technical expression: The sound pressure value will change over time. This change relationship
is expressed on the coordinate graph of the amplitude vertical axis and the time horizontal axis, which will produce a trajectory
of the sound pressure value changing with time. Sound state-the shape of the track of sound pressure changes over time.
In the product introduction, we will find some technical indicators related to the equipment. How will various indicators
affect sound quality? How big is its impact? Which indicator has the greatest impact? This is a topic that audio enthusiasts
often pay attention to and are discussed from time to time.
The phase characteristics of the sound system will directly
affect the sound state. Phase distortion will inevitably affect certain frequency components in music electrical signals,
causing them to be misaligned on the time axis. This will change the instantaneous value of sound pressure at certain timing
positions and will also produce micro-dynamic distortion in a short time interval.
The various distortions of the sound
system, they all change the signal waveform in the end, and specifically change the sound state and timbre.
Among various distortions, intermodulation distortion has the greatest impact on timbre. When a music
signal passes through an amplifier with intermodulation distortion, some frequency components that are not in the original
signal will appear on the signal spectrum, thereby changing the timbre.
Non-linear (harmonic) distortion will also
cause some frequency components not in the original signal to appear on the signal spectrum, thereby changing the timbre of
the sound. Unlike intermodulation distortion, the number of frequency components produced by nonlinear distortion has a linear
relationship with the number of original signal frequency components, but the relationship reflected by intermodulation distortion
is exponential (to be precise, it is called mathematically Combination relationship)).
The meaning of the distortion
Each amplifier includes multiple unit circuits. Each unit circuit is also composed of multiple circuit
segments. When each section and each unit circuit itself has large distortion, the non-linear distortion value of the amplifier
(from input to output) can be reduced through mutual compensation and large loop feedback of each section and each unit circuit.
The ideal degree is close to zero. However, these measures have not eliminated the non-linear distortion existing in each
segment and each unit circuit itself.
Segmented circuits with nonlinear distortion will inevitably produce intermodulation
distortion. A signal containing two or more frequency components, passing through a segmented circuit with nonlinear distortion,
will inevitably have additional frequency components that the original signal does not have. Once these intermodulation distortion
products appear, they cannot be separated or removed from the signal.
Intermodulation distortion and nonlinear distortion
are closely related, but they have different meanings. If the signal processed by the amplifier is a sine wave (only a single
frequency component), the nonlinear distortion index has a certain meaning. If this is a music signal (contains two or more
frequency components), the index of intermodulation distortion will be able to more fully reflect the overall characteristics
of the amplifier.
The technical indicators
For equipment users, the significance of technical
indicators is that there can be a unified standard to evaluate and compare the work quality and performance differences of
the same functional products of all parties. If the established technical indicators meet the working nature of the equipment,
the evaluation is valid. Audio equipment manufactured by modern technology usually has some perfect technical indicators.
So, can we effectively judge the quality and characteristics of their voices based on these indicators?
We can discuss
this issue with an operational amplifier as an example. If op amps of the same company, the same model, different origins,
or even the same model and different batches are installed on a typical audio circuit for testing. For some technical indicators
currently used to measure audio equipment, we can all measure the same value. However, when we install these operational amplifiers
on the same audio equipment for sound comparison, we will hear different sound effects.
For audio equipment, the above
example is a common phenomenon. It shows that these indicators are not enough to fully reflect the actual working quality
of audio equipment. Many static indicators are used to measure audio equipment in industrial production. However, in addition
to more directly reflecting the phase characteristics and intermodulation distortion of the sound quality of the audio equipment,
most of the static indicators will gradually lose their meaning as the signal alternating speed increases and the dynamic
increases. Therefore, based on the existing technical indicators, audiophiles may still be unable to effectively evaluate
the actual quality of the equipment in actual use.
Similarly, these indicators alone cannot effectively analyze the
sound characteristics of audio equipment. Below, we will analyze the inevitability of the sound characteristics of the device
based on physical principles (electronic principles obey physical mechanisms).
Please note: When using a WRT cable,
the sound characteristics described below can be accurately presented. If the audio system uses other cables, the sound state
may be somewhat distorted, and the apparent degree of characteristics will vary.
quality of grounding has a great influence on the stability of electronic equipment. Electronic equipment transmits or processes
electrical signals, and uses "ground" as a reference to establish a basis for comparison. If the "ground"
is unstable, the accuracy of the foundation will be shaken. Set up an independent ground for the audio system to avoid external
interference. The internal resistance of the grounding will affect the degree of mutual interference between the various components
of the audio system.
If we classify amplifiers by device type, we can divide them into
electron tubes, transistors, and integrated circuit amplifiers. Affected by the electrical characteristics and physical structure
of the device, various devices used in audio (low-frequency linear) circuits can basically have such characteristics: the
micro-dynamic filtering* of the tube amplifier is the largest, the transistor is the second, and the integrated circuit is
the smallest (but in In some applications, after the integrated circuit amplifier is combined with the peripheral circuit,
the strength of the micro-dynamic filtering may be stronger than that of the tube amplifier). The intensity of micro-dynamic
filtering controls the density of sound details. With the enhancement of micro-dynamic filtering, the original details of
the music will gradually decrease. In the circuit design, the intensity of the micro-motion filter can be controlled to improve
the smoothness of the sound, but the direction of control can only be enhancement.
* Low-frequency analog circuits
used in audio equipment usually need some measures to filter out noise, overshoot, and high-frequency interference. Regardless
of the original intention of adding these measures, they will correspondingly produce some negative effects of micro-dynamic
filtering. The weak micro-dynamic filtering only reduces the sound details. When the intensity reaches a certain level and
combined with loop feedback, these measures will produce an effect of compressing signal dynamics.
Here, by the way,
a frequently heard topic "Amplifier without Feedback". This feedback is of course negative feedback. Because positive
feedback is the oscillator. We need to understand a simple concept: linear circuit. Linear circuits are also called analog
circuits. The traditional amplifier is an analog amplifier. Now there is a digital amplifier in the audio market, that is,
a class D amplifier. Analog amplifiers are also called feedback amplifiers or linear amplifiers. Because no device can have
a completely linear amplification characteristic. To achieve linearity, the amplifier must introduce negative feedback. So
any linear amplifier must be a feedback amplifier.
Every amplifier design hopes to achieve a balance in the smoothness
of the sound, the details of the music, the sense of speed, and the micro dynamics. Because power amplifiers need to drive
complex inductive and capacitive loads, it is more difficult to satisfy this balance. Therefore, the design of some pre-amplifiers
has increased the consideration of matching certain power amplifier characteristics to achieve this balance in the overall
coordination of the system. Using this effectively, we can find many combinations of amplifiers that can be matched with each
Earlier preamplifiers have more functions. They have more complicated wiring,
making the sound richer, but also accompanied by some muddy. In the period when operational amplifiers were widely used, this
muddy sound has become the sound characteristic of audio equipment in this era. However, on some line amplifiers with relatively
simple circuit structure, we can still hear a relatively clean sound.
Later produced preamplifiers. As the signal source
gradually becomes more single, the circuit structure of many preamplifiers is closer to the line amplifier in design. The
circuit structure becomes simpler, combined with the improvement of component quality and technological progress, the timbre
of the amplifier can be controlled more artificially. Therefore, there are more preamplifiers with various sound effects for
us to choose from.
Some preamplifiers are equipped with tone or working bandwidth control functions. These functions
will change the phase characteristics of the amplifier, thereby changing the sound state.
There are some passive volume
controllers on the market that are used to replace preamplifiers. The use of such equipment will require: 1) High-quality
signal interconnection lines, whose length should be as short as possible, especially the output end interconnection lines;
2) The receiving end equipment needs to have high input resistance and low input capacitance. However, most semiconductor
devices do not have high input resistance; most vacuum tube devices do not have low input capacitance. Therefore, it will
be more difficult for this type of equipment to get a perfect fit. If the above conditions are not met, after using this type
of equipment, the frequency response and phase characteristics of the audio system will undergo considerable changes.
The audio system is connected to an analog equalizer, which will produce severely chaotic
phase characteristics. Changes in the phase characteristics will inevitably affect the sound state. The digital equalizer
has good phase characteristics. However, the signal requires A/D and D/A conversion in a digital equalizer, and the sound
quality depends on the functional quality of these conversion circuits. Digital equalizers with digital inputs and outputs
do not have the above problems. Many new generation professional mixers use this type.
quality of the power amplifier depends to a large extent on its driving performance. This drive performance can easily be
misunderstood as the output power, internal resistance and other technical indicators of the amplifier. We have no shortage
of examples to see which tube amplifiers with only a few watts of power output can still play melodious music. However, their
internal resistance is not very small, nor do they have good technical indicators. How much power the power amplifier can
output indicates how much power reserve it has. This is not necessarily related to drive performance. The reason is as if
the driving performance of a car is not necessarily related to whether the car has strong power. Unless this reserve power
is not enough for the speaker vibration system to produce the required motion. The power amplifier has good driving performance,
so that the speaker tray can accurately follow the signal waveform to move.
If we look at the speaker from another
angle, we can think of it as a linear motion motor. In this way, we can further understand the importance of drive performance.
Drive performance is related to the effectiveness of control. In many cases, the speaker's vibration system loses control,
resulting in machine-like inertial vibration, which is considered to be the original low-frequency component of music. In
fact, this is an example of poor driver performance. This type of sound is characterized by a single frequency as the main
component, and maintains the same sound pressure amplitude in a short period of time. It is similar to acoustic resonance
in a room, and we can easily recognize it from the sound of music.
The drive performance is not necessarily related
to the device type. But in this respect to achieve the same performance, different device types still have some differences.
The tube amplifier has an output transformer, and its driving force is relatively weak due to obstruction. If the amplifier
has a large internal resistance, when matched with a high-compliance speaker, there will be a longer period of under-driving.
In addition, because the amplifier uses an output transformer, the change in speaker impedance will be equivalent to the power
amplifier tube having a load that alternately changes between capacitive and inductive. This easily leads to phase distortion
of the signal. Faced with these situations, the drive design of the tube power amplifier will encounter more difficulties.
If vacuum tube amplifiers are required to have the same driving performance, their design also needs to solve their relatively
more unfavorable factors. Any power amplifier with an output transformer must encounter the above-mentioned problems. Avoid
using high-compliance speakers and choose speakers with relatively flat impedance characteristics, which can reduce their
requirements for amplifier drive performance. This choice is equally valid for power amplifiers of any type of device.
Drive performance is a technical topic. It refers to the ability of the amplifier to respond appropriately to the state
to maintain its drive. This involves many aspects of control technology issues, which are not part of the content of this
page and will not be discussed here.
The advantage of the high-power output amplifier is that after matching with the
speaker, the output of the amplifier can have a wider range to maintain excellent electrical/acoustic conversion linearity.
However, this only makes sense when comparing products of the same brand and the same series. Different brands or different
series of products may have different circuit structures or use different technologies. Its performance has been different,
and there is no such inevitability.
There is no absolute advantage in high-power output amplifiers. In the case of
the same power output, the high-power amplifier will cause greater disturbance to the energy supply and cause greater interference
to other devices. Adding power supply filter capacitors or modifying its internal power supply cannot effectively improve
this interference. It needs to reduce the internal resistance of the power supply network to solve this problem. Find out
how far the street grid transformer is from home, how many users the power supply line passes through, etc. These are all
factors of the internal resistance of the grid and external interference. Certain power filters may also increase the internal
resistance of the power supply network. In the case of the same internal resistance of the power grid, the interference of
the full class A power amplifier to the power supply will be relatively small. Higher efficiency circuits will produce greater
Class A power amplifier
There are two types of Class A power amplifiers, one is
half A type, and the other is full A type. Most half-A amplifiers are high-power amplifiers. These semi-A amplifiers work
in the Class A state when outputting 2~3W of power (some may be larger). If they exceed this range, they will switch to the
Class B state. The power tube of the full A power amplifier works in the A state all the way. The single-ended drive tube
amplifier is a full A type.
Compared with the class AB power amplifier, the power tube of the class A power amplifier
still needs to perform voltage swing under the high current state when the output is weak. Therefore, the speed of state changes
will be relatively low (longer response time). This circuit has a strong micro-motion filter, and the sound is relatively
smooth. The intensity of the micro-dynamic filtering of the semi-Class A power amplifier will increase with the increase of
the depth of the Class A state. When it reaches a certain level, the original details of the music will gradually decrease.
Full Class A power amplifiers have stronger micro-dynamic filtering.
Due to the slower speed, the intermodulation distortion
of the Class A power amplifier is larger. A small amount of intermodulation distortion products can change the timbre of the
sound. As the number of frequency components of a music signal increases, the influence of intermodulation distortion increases.
When playing some music with a wide frequency range (such as music played by a large orchestra), the sound will be messy.
The degree of confusion is related to the overall phase characteristics of the audio system.
One of the main features of the Class A power amplifier is that the power device will not be turned off during
the entire working process. This feature is easy to misunderstand, thinking that there is no cross distortion in Class A power
amplifiers. On the surface, the power device is not off, and it seems that the cross distortion can be eliminated. However,
this is not the case. The cross mentioned here includes two aspects. One refers to the transition of the on-off state of the
power device. The other is the process in which the sine wave trajectory passes through the positive and negative alternating
points of zero amplitude. The cross problem caused by the turning off of the power device has been solved in the AB circuit.
Another sine wave cross distortion is a problem that can never be completely solved, especially for Class A amplifiers.
Why is sine wave crossover distortion a problem that cannot be completely solved? This is a basic topic. We need
to explain from the formation of sine waves. In the Cartesian coordinate system, the vector whose starting point falls on
the coordinate origin (0, 0), takes the starting point as a fixed point, and performs circular motion at a constant angular
velocity. In motion, the magnitude of the end point of the vector on the Y axis (the horizontal projection of the end point
of the vector on the Y axis) is the amplitude of the sine wave corresponding to a certain radian. At the zero crossing point
(Y equals 0) of the sine wave, the circle tangent is orthogonal to the X axis. The circle tangent is the slew rate of the
sine wave trace. The tangent of the circle at the zero crossing point is a vertical line, which means: the sine wave has an
infinite slew rate at the zero crossing point. Regardless of the frequency of the sine wave, the situation where the slew
rate is equal to infinity at the zero-crossing point will not change.
For technical reasons, there is currently no
amplifier with a conversion rate equal to infinity, and such amplifiers will not appear in the future.
technical conditions, the main problem of sine wave cross distortion is speed. On the contrary, when the output is weak, the
state of the Class A power amplifier changes slowly, which is not conducive to improving the cross distortion of the sine
wave. Therefore, the full class A power amplifier only has the characteristics of not turning off the power device. Not only
can it not solve the problem of sine wave zero-crossing distortion, but it will also produce greater sine wave zero-crossing
distortion under the same conditions. In addition, the non-turn-off feature allows the power device to withstand greater voltage
swings. For existing power devices, this will have relatively poor linearity. In various test spectrograms, we can also see
that the distortion of the Class A power amplifier is greater than the distortion of the Class AB power amplifier.
we have made some explanations on the formation mechanism of sine wave crossover distortion. The technical indicators of sine
wave distortion are usually measured on audio equipment. However, the audio equipment handles music electrical signals in
actual work. Therefore, if we want to accurately assess the substantial impact of various distortions of audio equipment on
music playback, we need to discuss them in conjunction with the characteristics of music electrical signals.
The biggest feature of the tube amplifier is that people have the fun of "playing", and
the process is very convenient, and there is no requirement for technical knowledge in operation. If we do not have very high
requirements for music details and use a tube amplifier, we can easily replace the tube to meet everyone's own sound preferences.
Regardless of whether the brand or model of the tube is the same, each tube has its own sound personality. However, the
use of tubes to "play" sounds may only be suitable for preamplifiers. Because we rarely see the life of the power
tube can exceed 2000 hours. After this time limit, its puberty will disappear, and the sound will change with the electrical
characteristics of the tube. This is one of the biggest weaknesses of tube amplifiers. However, the Achilles heel of the tube
amplifier does not lie in this.
Such problems can be found in audio systems with high-resolution capabilities. When
the amplifier is replaced with a tube, you may Hard to get back the sound effect you originally liked. The electron tube used
in the preamplifier can have a relatively long life cycle, and some brands can reach 10,000 hours. However, they will gradually
age without being noticed, and at the same time, their voices will change accordingly.
with other equipment, the speaker is the only component in the audio system that does not reach the ideal level of technical
indicators. At the same time, it is also the most personalized component with the largest relative difference in electrical
Impedance Characteristic. In the effective working frequency range, no loudspeaker can have a horizontally
flat impedance characteristic. After the speaker is connected to a power amplifier with an output transformer, the change
in speaker impedance will cause micro-dynamic distortion of the amplifier. If the audio system uses a power amplifier with
an output transformer, choosing a speaker with a relatively flat impedance characteristic curve will help reduce this distortion.
Phase Characteristics. In the effective working frequency range, no loudspeaker can have horizontally flat phase characteristics.
By adjusting the placement of the speakers, the phase characteristics can be corrected to a certain extent. A speaker with
flat phase characteristics is more conducive to reproducing real sound, and its placement location can also have more choices.
Frequency Response Characteristics. In the effective working frequency range, no loudspeaker can have a horizontally flat
frequency response characteristic. Frequency response characteristics will affect the timbre of the sound, but this is different
from the change in timbre caused by distortion. This effect will be linear. It is only equivalent to the personality difference
of the same instrument but different timbre, and basically does not cause the change of the sound state.
Compared with other side rings, rubber ring speakers have greater machine inertia. Changes in the state
of the vibration system (paper tray, voice coil, etc.) will inevitably have a relatively long response time. This feature
may have the following two situations when the amplifier drives the speaker. 1) Under-drive, there is a strong micro-dynamic
filter, which will increase the ambiguity of the sound; 2) Over-drive, the vibration system will have overshoot. The chances
of the above two situations in the speaker will increase as the inertia of the machine increases.
Compared with the
rubber ring, the foam and cloth ring speakers have a smaller machine inertia, it is easier to obtain the cooperation of the
power amplifier, and the probability of underdrive or overload is relatively low.
Whether the loudspeaker will appear
under-driving and over-driving, depends on the interaction between it and the amplifier. As the inertia of the vibration system
increases, the speaker's requirements for amplifier drive performance also increase.
Every time you use the speaker,
you need to warm it up for a period of time before it can enter the linear working state. The loudspeaker has greater inertia
and requires longer Warm-up time.
In the audio system, the cable is the most special component
. A cable is an electronic circuit mainly composed of distributed components. The parameter values of the distributed component
are uncertain and the range of dispersion is large. This has the characteristic that different wires will have different transmission
characteristics. This can also be used to change the sound state and timbre. With the simple method of changing cables, you
can get the kind of sound and tone you like relatively easily.
Each brand of interconnection
cable has its own different sound characteristics. However, there may still be some differences in the sound effects of interconnecting
cables of the same brand or even the same model but in different production batches. Signal interconnection lines basically
have such characteristics. The same pair of interconnection lines are used in different systems, and the sound characteristics
of the interconnection itself remain unchanged.
Balanced or Single Ended
Balanced signal transmission
has stronger anti-interference ability and better isolation. Therefore, for signal transmission, the balanced mode always
has better transmission quality than the single-ended mode. However, when choosing a signal port, we also need to consider
other factors. If the device does not process the signal in a fully balanced manner, its input or output port needs to have
a single-ended/balanced conversion or reverse conversion circuit. The quality of these circuits will affect the sound quality.
Generally, as long as one of the two equipments processes the signal in a fully balanced manner, the effect of balanced
transmission will be better. If the two equipments are single-ended processing signals, you need to consider factors such
as the transmission distance of the signal, the functional quality of the conversion circuit, and the isolation design of
the equipment. Therefore, the signal terminal selection in this case often needs to be compared on a specific equipment to
distinguish the pros and cons of the signal connection.
Each speaker has its own
electrical characteristics, and there are significant differences between each model. Therefore, the speaker becomes the most
personalized unit of the audio system. Unlike signal interconnection cables, speaker cables are a type of power transmission
cable. Two issues, standing wave and real-time spectrum, will affect the sound state at the same time.
signals have a wide frequency band (10 octaves). The power transmission of each frequency component has its own standing wave.
And the respective standing wave amplitude will vary according to the electrical characteristics of each speaker. Combined
with the real-time problem of the frequency spectrum, after the music electric signal is transmitted, the waveform changes
of different speakers will be different, and the sound state will also be different. In this way, the speaker cable will inevitably
become a special component that matches the personality of the speaker.
For a specific speaker, using different cables,
the sound will have different sound states. With this function, you can get your favorite sound effect relatively easily by
changing the speaker cable.
To a certain extent, the power cord can be equivalent
to a filter. From the power supply connection point to the connection line before the power transformer generates the magnetic
field, there is always a certain degree of filtering. Different power cords may have different filtering characteristics.
On the other hand, each equipment may also need different filtering characteristics to get the best results. Therefore, if
the power cord of one equipment is used on another equipment, completely different results may occur.
Optical fiber can withstand electromagnetic interference, so it has certain advantages for long-distance signal
transmission. And this advantage will increase with distance. However, the photoelectric conversion and reverse conversion
circuits of the equipment will inevitably increase the jitter of the data stream. Therefore, whether the advantages of optical
fiber can compensate for the increased jitter in the device data stream may vary from system to system. Optical fiber is more
suitable for professional equipment for long-distance signal transmission over tens of feet. Household equipment only transmits
signals over short distances. The advantages of optical fiber may be difficult to compensate for the defects caused by photoelectric
conversion. Except in environments with strong electromagnetic interference, or the system must use a large number of digital
(or high-frequency) cables, home music playback systems try to avoid using optical fibers to transmit digital signals.
The sound of LP originates from the physical structure. No matter how the sound quality
is, the change of its sound pressure value will always have a transition time related to the physical structure. Therefore,
LP can basically have the characteristics of soft sound. To maintain this characteristic, accurate stylus pressure is necessary.
To maintain accurate stylus pressure under dynamic (working) conditions, the strut mechanism of the vocal arm will play
an important role. The arm strut mechanisms of different axial types have different following characteristics for the oscillating
movement of the stylus, which specifically affects the timbre and sound state.
The stylus pressure will change with
environmental factors, such as temperature, humidity, air pressure, etc. The pressure scale on the tonearm can only be used
as a reference, and it is difficult to rely on it to obtain accurate stylus pressure. For users of LP turntables, there may
be an unexpected gain with an accurate stylus pressure gauge.
RIAA Equalization (preset equalization) only has an agreement
on the amplitude-frequency characteristics, but does not establish a specification for the phase characteristics. Different
types of analog inverse equalization circuits have different phase characteristics. Therefore, different phono amplifiers
may also have different phase characteristics. The phase characteristics will affect the sound state, however, this parameter
usually does not appear on the product's technical indicators.
For the MC step-up
transformer, the input impedance of the MM amplifier is the load of the transformer. The capacitance on the load will have
a considerable negative impact on the signal transmitted by the transformer. Under certain conditions, the transformer has
the characteristics of capacitance/inductance conversion. This characteristic makes the capacitance on the load equivalent
to an inductance in series with the transformer input. This will inevitably produce strong micro-dynamic filtering, causing
serious loss of high-frequency components of the music signal.
Therefore, if the MC step-up transformer is used, you
need to: 1) Minimize the input capacitance of the MM phono amplifier; 2) The output terminal interconnection line must be
of low capacitance and shorten the length as much as possible. Regarding the first point, compared with semiconductors, electronic
tube equipment generally has a larger input capacitance, so it is not easy to meet this requirement.
In the history of audio development, audio CD is the first music signal source that does not require the
use of preset equalization in its standard. This provides a solid foundation for the signal source to obtain flat phase characteristics.
The sound of CD is also related to the physical structure, which is a bit similar to LP.
However, the impact of CD structure quality on sound quality is quite different. In the extrusion process of CD disc production,
the physical properties of the plastic inevitably lead to the slope of the pit edge with a short cooling time. This slope
becomes the gray area between digital states 0 and 1. The length of the cooling time will change the width of the gray area,
and specifically control the degree of data jitter. The data will have errors due to this jitter, and even after the data
is decoded, there will be analog signals that do not match the original record. For information on the mechanism that causes
CD data errors, see CD Disk Data Jitter.
CD optical disc media has such characteristics, which puts forward more stringent
requirements on CD players. Even so, if some high-quality CD discs are paired with a high-quality CD player, the sound quality
will still be better than other audio sources. For example, XRCD has good sound effects on many HI-End players.
codes AAD, ADD, DDD marked on the CD disc not only indicate which stage of the technology is used in the music recording on
the CD disc. Through these codes, we can also know whether the music signal on the CD is processed by an analog mixer. Analog
mixer will affect the sound quality of music playback from the aspect of phase.
The sound quality of an audio CD will
not only be affected by burning and post-production, but the structural quality of the disc will also affect the accuracy
of the data and ultimately affect the sound quality. The production process of some CD discs shortens the cooling time to
increase productivity. As a result, the quality of the pit structure representing the data is reduced. The amount of jitter
of CD disc data has also increased. We can distinguish these CD discs by simply observing the transmittance and uniformity
of the reflective layer. CD discs with relatively thick and uniform reflective layers usually have a longer cooling time.
They will always have better structural quality.
The setting time of multi-bit
digital/analog chips is relatively short, and can be converted more accurately and faster, so the sound detail density is
higher. Many early CD players were equipped with this type of chip.
The one-digit digital-to-analog chip has poor conversion
accuracy and softer sound. One and multiple digital/analog hybrid chips are also used in recent CD players. The electrical
characteristics of this type of chip are between one-bit and multi-bit chips, and are closer to multi-bit chips. CD players
produced in later stages mostly use the above two types of chips.
In the post-production of CD Transports, they used
a more mature digital signal processor (DSP). These DSP chips include a 32Kbit CIRC decoder memory, which can process data
faster, so there are more time resources to correct more data errors. The decoder with 8x digital filter and multi-bit digital/analog
chip is used as an analog unit with post-production CD transmission. This method combined with a CD player can usually achieve
higher detail density.
If the CD player uses an external clock, it needs to be
equipped with a high-quality digital cable to transmit the clock signal in order to avoid the clock's large jitter after long-distance
transmission (relative to the internal clock). We can use the stage depth in music playback to compare the jitter of the clock.
A CD player with less clock jitter has a deeper stage and a quieter music background when playing music. At the same time,
the environmental sound will be clearer and closer to the reality (using the environmental sound to identify the degree of
restoration of the original music details, the easiest to get an accurate judgment. You can also use this method to compare
the degree of jittering CD disc data).
For the Up-sampling, please refer to The quality
of audio equipment.
SACD is another digital format music source that uses PWM (Pulse Width
Modulation) encoding. At present, SACD players have not solved the problem of noise in the frequency band above 40KHz after
DSD decoding. For audio systems using such signal sources, avoiding the use of amplifiers with broadband response characteristics
can reduce the interference of such noise.
Compared with CD, SACD disc has a higher data storage density. Due to the
use of plastic as the data carrier, data stream jitter is more difficult to control. Therefore, under the same technical conditions,
SACD playback will be more prone to data errors. For 24bit/96KHz and DVD Audio digital music formats, because they also have
a higher data storage density, they will also encounter this problem.
About various coding formats
digital music formats such as CD, SACD, DVD Audio, 24bit/96kHz, many people have compared their sound quality. Regardless
of whether the evaluation of these comparisons is positive or negative, their statement is basically correct. This includes
companies that develop coding formats, and their claims about the superiority of coding formats are also correct. These conclusions
and statements may contradict each other. The reason is that there are some differences between ideals and reality. In principle,
24bit/96kHz is better than 16bit/44.1KHz, which is inevitable. But need to meet such a condition: the playback device can
read the correct data, and can accurately convert the data into an analog signal. In actual use, the extent to which the playback
device satisfies this condition determines the sound quality and the size of the difference, which specifically affects the
result of each comparison.
Another topic of the same nature is the difference in sound quality between CD and LP. After
the CD appeared, the discussion on this issue did not stop. Until today, thirty years later, LP is once again sought after
by fans. This phenomenon only reflects the actual CD in use, and there is indeed a gap between sound quality and LP that cannot
be underestimated. Just like the accuracy of emotional expression that is essential in music playback. Of course, if we regard
music as language, the accuracy of its emotional expression is also very important. We also compared the sound of CD and LP.
In our comparison, audio CD music playback has better performance. This is reflected in some singing performances. We can
feel that singers have appropriate emotional expressions when performing works, and music can more accurately depict the artistic
conception of lyrics. This is because CD has a technical foundation that provides more musical details. When the player gets
the correct data, the sound quality of an audio CD is of course better than that of an LP record. However, this result cannot
represent a general phenomenon. This is also because the quality of CD and LP sound quality and the degree of difference are
also restricted by the conditions of whether the playback device can obtain the correct data. So our comparison result may
be different from others.
Many factors affect the gap between ideal and reality.
With the consumer-grade playback equipment we currently use, and the use of plastic discs as data storage media, it is difficult
for the player to correctly obtain the data on the CD with the data storage density of the CD. For digital music formats with
higher data storage density, more errors will occur when the player reads the data. The superiority of these more advanced
formats is not enough to make up for the loss of sound quality caused by data errors.
As more and more data is generated,
players need to have a higher speed to process the data. As the operating speed of the device increases, the frequency of
the bit clock must be increased accordingly, that is, the cycle time of the bit clock will be shortened accordingly. Under
the same technical conditions, as the period of the bit clock is shortened, the jitter of the bit clock relative to the period
time will increase accordingly. At the same time, as the bit clock period is shortened, the jitter of the data stream relative
to the bit clock period will increase accordingly. In other words, as the working speed of the equipment increases, the probability
of data errors also increases.
Analog signal accuracy
D/A chips produced by the same technology.
Compared with low frequency, high frequency sampling will increase the error component of the analog signal after digital-to-analog
conversion. The process of converting each digital data into an analog signal requires a short settling time (settling time)
to make the analog value accurate. The voltage (or current) value after this stabilization time is the value that the analog
quantity should have.
High-frequency sampling will have a greater number of settling times, and the amount of error
(the amount within the settling time period) will occupy more time space. Therefore, when the sampling frequency is increased
to a certain extent, the time for the accurate value of the analog quantity is shortened, and the time for the error value
is increased. That is, the proportion of analog signals containing errors increases. The influence of the settling time on
the accuracy of the analog signal will subsequently reach a level that cannot be ignored.
The above-mentioned problems
are just some of the many shortcomings. They affect the sound quality of music playback in terms of data correctness. Although
in theory, many digital music formats and sound quality enhancement modes have some advantages. However, due to various restrictions,
they may not currently bring the expected results. There are some differences between ideals and reality, and it is necessary
for our technicians to reduce these differences. CD disc data low-jitter processing Tai Chi backup is an improvement measure
for audio CD data prone to errors in actual use. It is further confirmed that whether the playback device can obtain the correct
data is the key to whether the advanced encoding format can exert its advantages.
Last revision date: Aug-2021


Along with the rocket development of industry and technology, we must fully acknowledge the severe impacts of climate change. In the long run, protecting the environment and finding more sustainable energy sources is what guarantees our existence on Earth. Therefore, scientists have come back to utilize natural and renewable energy such as wind power, solar power, or tidal power. Yet, there is still a long road to fully adopt these alternatives, and machine learning can be the perfect ally to shorten the process.
Why machine learning is the perfect match for renewable energy
At the first hearing, no one could find the connection between machine learning and renewable energy. Yet, the unique characteristics of this industry are the perfect fit for the technology to showcase its full potential.
Renewable energy comes from renewable sources, which are usually what mother nature has already offered us. Some of the most popular sources are sunlight, wind, rain, tides, waves, and geothermal heat. Although holding great possibilities, these recyclable sources are hard for humans to control due to the unpredictability of nature. Our ancestors have come up with general indicators and annual forecasts for common weathers like when the rainy season is likely to start. However, they are showing little help over time due to the negative impacts of climate change.
In 2017, nearly 80% of global energy sources came from fossil fuels. To protect the environment as well as avoid overexploiting, governments are focusing on the long-term development of renewable energy. The first quarter of 2020 witnessed a 1.5% increase in global use of renewable energy in all sectors compared to 2019. Furthermore, countries must at least triple the production of global recyclable power, such as wind and solar, to achieve climate neutrality goals by 2050. Following this increasing adoption of renewable energy, scientists are under huge pressure to provide more accurate weather forecasts.
Since the beginning of time, meteorologists have collected weather data; the first meteorology document dated back to 350 BC. This data has been building up every day along with the development of mankind. To process all the information and transform them into useful insights for renewable energy implementation, machine learning is the only plausible choice with smart pattern-based prediction and huge data analysis.
More than an efficient roadmap to change the environment, machine learning is the key to open new possibilities in the power sector. Some of the most noteworthy benefits that machine learning offers to the future of the renewable energy industry include:
- Substantial and precise inspections: Governments and organizations can now get access to flawless analysis based on a rich history source.
- A cost-effective and resilient energy grid: With accurate forecasts, meteorologists can suggest a suitable energy plan to the authority to support particular demands. The new recyclable energy will soon be considered “dispatchable,” which means it can provide a specific amount of power when needed.
How machine learning optimizes renewable energy production and consumption
Weather and risks prediction
The most important factor in ensuring the success of a renewable energy plan is weather and risk prediction. Usually, scientists research the physics of the weather itself and compare them with previous phenomena. However, with machine learning, this process has been greatly simplified.
Daily weather data is saved to a database, and then computers will run the system to create predefined models. If the same phenomenon happens in the next period, the application can automatically sort them into the correct weather model. Furthermore, each model is programmed to predict how the weather will affect the result of the renewable energy plans. The forecast will help organizations to further understand how the environment can facilitate the energy grid and focus the resource on potential time frames. Comprehensive machine learning can forecast up to 30 days prior, which can be seen in IBM’s system.
The US Energy Department has witnessed a 30% increase in solar power predicting accuracy thanks to machine learning. This machine learning application in renewable energy has also been implemented successfully by the UK’s National Grid. Combining satellite imagery, observation, and deep learning, they have summarised the data of hundreds of power hubs throughout the country to forecast the weather accurately. “If you’ve got a cold front moving in and [a model] has seen something similar before, we can predict the likely impact of that front on solar generation.”, said James Kelloway, energy intelligence manager at the National Grid’s Electricity System Operator division.
Energy demand forecast
Not limited to only following climate changes, machine learning takes a further step into forecasting power demand. For example, summer is when the need for power climbs up rapidly, yet this is still only a general statement. To better analyze the fluctuation and prepare practical strategies, scientists rely on the power of machine learning.
Sharing the same methods as weather forecasting, this machine learning application in renewable energy tracks changes and behaviors of users when consuming energy on different periods then builds up a model for each phenomenon. After that, it suggests a number based on historical energy usage data. The information can tell organizations to generate more energy or cut down on unnecessary sources.
For example, Verdigris Technologies is a technology company that provides a software platform to optimize power consumption. With an IoT hardware installation and smart sensors attached to the energy grid of the clients, Verdigris Technologies can smartly identify insufficient energy sources. One of their customers, W Hotel San Francisco, has recognized $13.000 preventable energy annual losses in their kitchen just after 3 months of using the system.
Intelligent maintenance and infrastructure design
One factor that determines the win or loss of a renewable energy implementation is the maintenance post-installation. Unlike other sources, natural powers don’t get generated from a self-contained factory. For example, solar plants or wind turbines cost thousands of dollars to build, yet they are usually in the middle of nowhere, with little intervention from people. It will be a smart move to proactively take a closer look at the performance of these installations. When you successfully maintain the health of the input, your energy grid could easily and seamlessly cover the output demand.
Machine learning takes advantage of both past and present data to develop the future performance of the energy system. Some of the most common intelligent maintenance are anomaly detection, failure prediction, and automated monitoring. Researchers have confirmed that with AI applications, predictive maintenance is up to 25.3% more effective and 24.6% more accurate.
Applications of machine learning in renewable energy also opens a new door for smart infrastructure design or smart buildings. According to GlobeNewswire’s report, the global smart building market is predicted to reach $127.09 billion by 2027. More and more architects are building houses with an intelligent energy management system as the core of the design. Appliances are powered by solar power and controlled by AI or voice command, which allows us to command them to auto-perform simple tasks remotely.
On a smaller scale, you can take a look at how Verv – an AI-based tool, supports energy management. This application records how household appliances consume energy and alerts users when a device is left unconsumed for a long time. This helps saving energy expenses as well as protecting devices not to be overused.
Smart energy grid
Following proactive maintenance, an intelligent energy grid is what companies are looking for when applying machine learning in renewable power. One of the most challenging tasks for any energy plan is how to distribute energy to multiple locations effectively. The unpredictable traits of natural resources such as solar or wind power make this issue much more complicated. However, machine learning has the perfect answer to this riddle.
By implementing machine-based applications, companies can avoid fraudulent actions such as electric theft and provide scalable power strategies for long-term development. A balancing and smart energy grid can help organizations to answer tricky questions, such as:
- The most and least power-needed locations
- The highest and lowest power supplying locations
- The frequency of blackouts
- The locations require additional energy-generating infrastructure
- The abnormal power-consuming locations
Machine learning is taking step by step closer to managing the energy grid to fit human needs. Jack Kelly, co-founder of non-profit climate change research and development lab Open Climate Fix, proposed: “It is still quite manual, so it’s humans looking at what’s happening on the grid now and humans instructing generators to change their behavior to try and better match demands, over time horizons of an hour or less typically.”
A great example of how machine learning can support energy control comes from the DeepMind AI of Google. Its purpose is to cut down on energy consumption and emission from energy usage. According to Google, the application has managed to cool off Google’s data servers by 40%.
Learn more about Machine Learning at: The Comprehensive Guide to Understand Machine Learning and Deep Learning
Machine learning is the answer to the seemingly impossible challenge of implementing recyclable power. Thanks to technology, the distance between planning and practical usage is shortened tremendously. Meteorologists, companies, and governments now have credible evidence and analysis to create a concrete long-term plan for sustainable development. All can be achieved with machine learning applications in renewable energy.
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We offer a few different solar light options. The first is mounted Solar Powered Dock Lights. These are high quality lights that will last for years on your dock. You be able to see your dock in low light condition and it turns on automatically.
We also have pole lights that are completely solar powered. They will give your dock lighting automatically from dusk to dawn.


Despite having the greatest wireless routers, do you have poor wi-fi signals? Even if you have the greatest wireless routers, do you have signal difficulties in specific sections of your workplace or home? Wi-Fi-blocking materials such as concrete, metal, thick walls and floors, glass, distance, and signal interference from other devices have contributed to poor and mediocre wi-fi connection quality.
To solve the wireless coverage problem, the first thing you need to do is boost your wi-fi connection by employing strategies such as relocating your router or moving it to an open central spot. Regrettably, this does not always work. In such cases, you’ll need to take further precautions like buying a long-range antenna, getting a new wi-fi device, or just altering the router’s antenna. If you’re still having trouble improving your wi-fi connection, look into wi-fi signal boosters, which are specifically intended to provide the finest wi-fi network coverage.
What is a Wi-Fi Booster?
A wireless range extender is the correct definition of a wi-fi booster. It’s a gadget that receives a signal from a wireless router or access point and rebroadcasts it to form a second network. It acts as a bridge between a wi-fi router and a wi-fi device outside the range of a wi-fi router’s signal. The wi-fi booster first connects to an existing wi-fi network, and once it’s connected, it acts as a wireless access point for wi-fi devices to connect to.
So, as an example, most people who have internet service in their home will most likely have a wi-fi router that will broadcast a wireless signal throughout their home so that their wireless devices can have internet access. But sometimes, there might be issues where the wireless signal is not strong enough to cover the entire house.
How Does It Work?
A wi-fi Booster is a separate device placed between the dead zone and your router, to which it is hooked up either wirelessly or through a wire. It works by grabbing the router’s existing signal and broadcasting it on another channel, relaying the connection into the spot you want to be covered. In its most basic form, a wi-fi Booster serves as a conduit between the dead zone and your router, expanding the latter’s signal across the remainder of your house.
As a result, an internet connection may be discovered almost everywhere, regardless of obstacles. Wi-fi boosters, as handy as they are, are far from failsafe. Their efficacy is determined by where they are located. The device must be placed close enough to it to pick up the router’s signal. It must, however, be far enough away from the dead zone to rebroadcast the signal.
Types of Wi-Fi Booster:
Wi-fi boosters are of two types: 1- Wireless Wi-fi Boosters 2- Wired Wi-fi Booster
1- Wireless Wi-Fi Booster:
A wi-fi booster allows multiple wired and wireless devices to join together in a local area network. It will broadcast a wi-fi signal so that wireless devices can connect to it, and it also has a built-in switch with several network ports so that wired devices can connect to it using Ethernet cables. And then that wi-fi router will directly connect to a modern to give those devices internet access.
2- Wired Wi-Fi Booster:
Wired wi-fi Boosters are a great or desirable option for achieving high connection rates with minimal disturbance. Wired wi-fi boosters attach to your existing coax line in your office or wherever you wish to connect to expand your wireless network to regions where signal strength is weak.
Is It Worth Investing in a Wi-fi Booster?
If you have connectivity issues due to a dead zone in your home, then a wi-fi booster would be extremely useful. Not only will it allow you to browse the web in that particular spot, but it will also increase the number of places from where you can work. Unfortunately, a wi-fi booster won’t cut it if your goal is to increase internet coverage throughout your entire home. For that, you will need a new router or a new service provider.
Considerations When Purchasing a Wi-fi Booster:
If you are planning to purchase a wi-fi Booster, you must need to consider the following things.
Range may help you get an estimate of the coverage provided by your wi-fi Booster.
Wi-fi Boosters are meant to Boost wi-fi coverage and not increase the speed directly. However, ensuring that the speed provided by your wi-fi Booster is not less than that provided by your router will enable a connection as fast as your wi-fi.
An ethernet port in your wi-fi Booster is useful because you can directly connect a wired device to it for high-speed internet.
Frequently Asked Questions (FAQs)
Do Wi-fi Boosters Help to Get Rid of Dead Zones?
Answer: wi-fi boosters help you get rid of dead zones and let you set up an access point mode by connecting it to an internet source.
Will a Wi-fi booster help you enhance your wi-fi signal?
Answer: It depends on where your device is positioned. The wi-fi booster might assist in strengthening the wi-fi signal. If the internet service is not the bottleneck, a better wi-fi connection might aid with online streaming to the Broadcast. It’s best to validate this by testing the Screen adjacent to the internet service router.
What’s the difference between a range extender and a wi-fi booster?
Answer: wi-fi range extenders are also known as wi-fi repeaters, and wi-fi boosters are frequently used simultaneously. While they both increase the area covered by your wi-fi, they do it in distinct respects.
How can you tell whether your wi-fi booster is functioning properly?
Answer: The improvement in signal in the weak zone and dead zone sectors is the first evidence that the booster is operating. However, if you are a numbers person who prefers hard evidence, speed tests are excellent tools for analyzing wi-fi signal changes.
To summarize, you better understand how wi-fi boosters’ function by reading the preceding article. It gives optimal wi-fi coverage for your house or workplace. The wi-fi booster will increase network coverage so that your laptops, tablets, and smartphones can stay connected with less interference. With wi-fi boosters installed, you can enjoy continuous streaming, gaming, and other online activities in any section of your house or business.


AUSTIN, Texas — The University of Texas at Austin will be a key player in LaserNetUS, a new national network of institutions operating high-intensity, ultrafast lasers. The overall project, funded over two years with $6.8 million from the U.S. Department of Energy’s Office of Fusion Energy Sciences, aims to help boost the country’s global competitiveness in high-intensity laser research.
UT Austin is home to one of the most powerful lasers in the country, the Texas Petawatt Laser. The university will receive $1.2 million to fund its part of the network.
“UT Austin has become one of the international leaders in research with ultra-intense lasers, having operated one of the highest-power lasers in the world for the past 10 years,” said Todd Ditmire, director of UT Austin’s Center for High Energy Density Science, which houses the Texas Petawatt Laser. “We can play a major role in the new LaserNetUS network with our established record of leadership in this exciting field of science.”
High-intensity lasers have a broad range of applications in basic research, manufacturing and medicine. For example, they can be used to re-create some of the most extreme conditions in the universe, such as those found in supernova explosions and near black holes. They can generate particles for high-energy physics research or intense X-ray pulses to probe matter as it evolves on ultrafast time scales. They are also promising in many potential technological areas such as generating intense neutron bursts to evaluate aging aircraft components, precisely cutting materials or potentially delivering tightly focused radiation therapy to cancer tumors.
LaserNetUS includes the most powerful lasers in the United States, some of which have powers approaching or exceeding a petawatt. Petawatt lasers generate light with at least a million billion watts of power, or nearly 100 times the output of all the world’s power plants — but only in the briefest of bursts. Using the technology pioneered by two of the winners of this year’s Nobel Prize in physics, called chirped pulse amplification, these lasers fire off ultrafast bursts of light shorter than a tenth of a trillionth of a second.
“I am particularly excited to lead the Texas Petawatt science effort into the next phase of research under this new, LaserNetUS funding,” said Ditmire. “This funding will enable us to collaborate with some of the leading optical and plasma physics scientists from around the U.S.”
LaserNetUS will provide U.S. scientists increased access to the unique high-intensity laser facilities at nine institutions: UT Austin, The Ohio State University, Colorado State University, the University of Michigan, University of Nebraska-Lincoln, University of Rochester, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory.
The U.S. was the dominant innovator and user of high-intensity laser technology in the 1990s, but now Europe and Asia have taken the lead, according to a recent report from the National Academies of Sciences, Engineering and Medicine titled “Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light.” Currently, 80 to 90 percent of the world’s high-intensity ultrafast laser systems are overseas, and all of the highest-power research lasers currently in construction or already built are also overseas. The report’s authors recommended establishing a national network of laser facilities to emulate successful efforts in Europe. LaserNetUS was established for exactly that purpose.
The Office of Fusion Energy Sciences is a part of the Department of Energy’s Office of Science.
LaserNetUS will hold a nationwide call for proposals for access to the network’s facilities. The proposals will be peer reviewed by an independent panel. This call will allow any researcher in the U.S. to get time on one of the high-intensity lasers at the LaserNetUS host institutions.


27 January, 2020
King Abdullah University of Science and Technology (KAUST) in collaboration with ARMOR, a global technology company and pioneer of solar solutions has created a new style of outdoor seating, incorporating flexible, lightweight and semi-transparent solar technologies.
05 January, 2020
Wearable electronics could be perpetually powered by stretchy, self-mending materials that use body heat to generate electricity. Three carefully curated organic compounds have been combined to develop a prototype thermoelectric material that is both stretchy and self-healing, can generate its own electricity, and is robust enough to withstand the stresses and strains of daily life.
27 June, 2019
Some of the vast amount of wasted energy that machines and devices emit as heat could be recaptured using an inexpensive nanomaterial developed at KAUST. This thermoelectric nanomaterial could capture the heat lost by devices, ranging from mobile phones to vehicle engines, and turn it directly back into useful electricity.
11 June, 2019
Organic solar cells could soon rival traditional silicon-based photovoltaic technologies in terms of conversion efficiency. A team from the KAUST Solar Center has developed a computational approach that provides practical performance targets and useful rules to help design and develop material systems for optimal organic solar cells.


Nowadays the AC mains network is heavily polluted by various domestic appliances, industrial electrical consumers etc. This can lead to buzzy toroidal transformers (especially the power ones). Proposed DC trap (blocker, filter) will remove or at least lower the buzzing.
Schematic is similar to this one used in well known Vladimir Shushurin’s Lamm-1 amplifier. An article with in-dept explanation of how DC blockers work can be found on Rod Elliot’s site (https://sound-au.com/articles/xfmr-dc.htm).
Here is offered device capable to handle VERY HIGH CURRENTS (up to 30 Amperes intrinsic handled current!!!) assembled in a steel case – black powder coated.
Because of such high currents using a standard PCBs is not possible. Instead of that a 2mm. thick pure copper bussbars are used to connect the filter’s parts.
In order to carry such high loads the part’s values are upraised with 4 x 47 000 uF capacitors, 25W power resistor etc. For further description of the High-Power DC Blocker see here: High-Power DC Blocker Unit
Note that the Blocker undergone a redesign and now it has 6 discrete diodes which allows it to block DC shifts up to 2V!
The capacitor block is firmly connected to the bottom of the case with brackets and rubber sheet.
The input AC connector is Schurter C20 or C14 IEC Inlet. The type of the input AC connector determines the unit’s max. handling current – 20A with C20 IEC inlet and 10A with more widespread C14 inlet.
There are two high-quality AC outlet located on the front panel along with the IEC AC Inlet. Each AC inlet can handle not less than 13A AC output current.
The customer can chose between EU Schuko, UK, US, French, Australian, Switzerland and even exotic Brazilian style AC Outlets.
There are 4 rubber feet on the bottom of the case which ensure that case will not scratch the underlying surface.
Unit’s weight: 3 kg.
What the buyer will receive:
The package will contain 1 pcs. FULLY ASSEMBLED and tested HIGH-POWER DC trap/blocker/filter for toroidal transformers (toroids) in steel case.
The unit will be shipped with Priority AirMail Registered (or equivalent courier service where applicable). The tracking number will be sent to the customer after shipment.
Submit your review
I changed amplifiers recently to a very hi power unit (825W into 4Ohm) and felt it was starved of power using the standard DC Blocker. The hi power unit is hands down one of the best investments I have made to date. The sound stage exploded, the transients are noticeably better and the detail is just astonishing.
The blocker has really blown the lid off my musical experience. A must buy!


What Is Artificial Intelligence?
Artificial Intelligence (AI) has been the focus of speculation and excitement since its inception decades ago. The reality of AI is finally beginning to catch up with science fiction. This technology is beginning to permeate our entire lives in ways that we may not even be aware of.
What is AI?
AI is any system or machine that can improve upon itself by using the information it collects in a way that reflects how human intelligence works. In essence, AI is the capability of a more advanced learning process for computers and machines. It’s the process of creating intelligent machines capable of improving and learning as they collect data, parse it, and make logical conclusions toward their own evolution.
Some examples of AI include customer service chatbots and social media algorithms. The pinnacle of human intelligence, things like speech recognition, advanced decision-making, and visually identifying objects and faces, has now become something that AI is capable of.
While movies and books often portray AI as being a threat to the human species, many are excited about the reality of AI making our lives easier, better, and more efficient. For now, companies are utilizing AI as a premier solution to many problems.
To truly understand AI, it’s important to dissect the “intelligence” part of the catch-all phrase. Intelligence, in the context of Artificial Intelligence, refers to the computational abilities of goal-achieving for a system. In short, if a system is capable of fast and abundant computations in order to achieve its preconceived goal, we could call it “intelligent.”
For obvious reasons, human intelligence has always marked the benchmark for how we wish our machines could operate. When many envision what AI could become, what they are really aiming for is the capability standard of the human brain. Historically, human intelligence has always had a greater capacity for storing memories, multitasking, communicating socially, decision-making, and being self-aware. There are still many aspects of decision-making and thought processes that artificial intelligence can’t pull off. The way the human brain operates is still somewhat of a mystery to us so it’s only natural that it’d be difficult to program that into a machine.
When did AI become a thing?
While not every researcher or developer has ambitions that rival science fiction movies, AI development goals of enabling computers to do anything a human mind can do are standard. Alan Turning, an English mathematician, is considered by many to be the earliest champion of AI’s potential. His lecture in 1947 focused on AI and it was the start of a cultural shift toward the possibilities of how computers might evolve. The Turing test was essentially a test proclaiming that if a computer could match human intelligence and convince an outside observer of a human-like intelligence, then it was to be considered “intelligent.”
Machine learning, deep learning, and AI
More than 70 years later, many believe we’ve exceeded Turing’s benchmark for computer intelligence. The term “artificial intelligence” is often mentioned together with machine learning. AI and machine learning are not separate things, rather machine learning is a tool used within AI development. AI works by taking in an abundance of data and running it through algorithms and learning from the patterns along the way.
Machine learning, on the other hand, seeks out conclusions from data through the use of neural networks. This pattern-seeking behavior allows a computer to learn. Previously, this hadn’t been a hallmark of computers as they’d always completed functions that they’d been programmed to do and nothing more. Accompanying machine learning in conversations about AI is the concept of deep learning. Deep learning is essentially machine learning within layers and layers of huge datasets.
Why is AI important?
Beyond just a sense of accomplishment for how far computer intelligence has come, AI offers several tangible benefits. AI offers greater automation for certain tasks. Because a computer cannot exhaust itself or run out of mental energy, it can perform repetitive tasks that a human would need to do manually. AI can also work a 24-hour day every day of the week, whereas a human cannot. It can provide a higher-quality analysis. With a heavy focus on a single task or function, AI can analyze datasets or difficult problems at higher speeds than a human brain can. It can improve the effectiveness of our processes and functions. It can cut down on errors caused by human judgment.
All of these add up to the enhancement of products and services delivered to end users. Additionally, these AI capabilities mean a reduced overhead cost for many companies. Without the need for staff members or teams comprising multiple people, AI can run at full capacity doing what it needs to do while delivering higher ROI for its performance.
With these core benefits of AI, we may see boring (or dangerous) jobs as a thing of the past, at least for humans. We may see a hugely improved output from departments and companies with a radical growth in speed and efficiency.
Who oversees the development of AI?
Many have warned us about the potential hazards of AI. Elon Musk famously stated: “Mark my words, AI is far more dangerous than nukes” and then went on to ask “why do we have no regulatory oversight?” There’s no shortage of movie references alluding to the possibility of AI gone awry, as well as influential people questioning where we’re headed. So, what’s in place to make sure that doesn’t happen?
Some oversight must be implemented to ensure our future with AI is beneficial for all. What will be the most effective type of oversight or regulation? To understand the answer to that question, we need to realistically look at the threats AI poses. Before we worry about AI taking over, there are a few much more pressing ways that AI may disrupt our way of life.
Job automation is no longer a distant potential danger of AI technology. Jobs are already being automated and due to this, people are being put out of jobs. What’s worse is that we haven’t planned for this as a society. Millions of people work in jobs that are under threat of being replaced by automation via AI within the next decade. With this automation and the subsequent layoffs, we could see increasing unemployment rates. The fact is, certain industries and jobs would be affected much more quickly by early automation by AI than others.
Another potential danger of AI coming in the near future would be the malicious use of this powerful technology. With great power comes great responsibility and as soon as AI's sheer potential becomes accessible to all, we're sure to see it make its way into the hands of malevolent criminals, hackers, terrorists, and states. We may also see privacy and misinformation issues with burgeoning AI capabilities. This prospect has spurred a sort of AI arms race where many countries and companies are speeding innovation of AI in both benevolent and malevolent forms to stay ahead of unforeseen enemies and competitors.
For now though, many organizations are still figuring it out. The truth is, we’re entering uncharted territory and no one knows for certain. It will likely follow much of previous technology in the fact that it can be used for both good and bad.
Who is leading development of AI?
Tech giants like Google and Facebook have made strides to innovate and incorporate AI into the fabric of how they run their companies and deliver their services. But it’s not only the large corporations that are making use of AI. Startups all around the world specializing in AI-focused products and services are popping up quickly. Orbital Insight provides insights and forecasts to various industries using satellites and drones that parse through AI-gathered data. SoundHound helps you identify songs through its AI function and aims to provide deeper capabilities in the voice and conversational intelligence field. Non-profits like OpenAI are creating artificial general intelligence, similar to human beings with a focus on safe and responsible AI innovation.
Acer's aiForge is a development tool that's allowing schools and businesses the much-needed flexibility in training both simple and complex AI solutions. It enables organizations to simplify and prioritize tasks as they see fit while reducing the amount of time needed to bring their models and solutions into reality. This will surely accelerate innovation in the industry.
But AI development is not limited to the big tech giants. Anyone can get involved in AI work just like programming has become an open opportunity for many people spread out across the world. While we’d be right to feel some caution about unrestricted AI development, it’s clear that AI is a promising field and will likely change the future of humanity in many positive ways.
*The opinions reflected in this article are the sole opinions of the author and do not reflect any official positions or claims by Acer Inc.
About Alex Clark: Alex is a contributing writer for Acer. Alex is a Texas-based writer and B2B email marketing strategist specializing in helping technology brands connect to their customers. He has lived all over Asia and has consulted with business clients in numerous industries to grow their brands.
Alex is a contributing writer for Acer. Alex is a Texas-based writer and B2B email marketing strategist specializing in helping technology brands connect to their customers. He has lived all over Asia and has consulted with business clients in numerous industries to grow their brands.


VOCSN is an innovative life-support device that combines five respiratory therapies – ventilation, oxygen, cough, suction and nebulisation – in a single system. No larger than a lunchbox, the device is 70 per cent lighter and smaller than comparable machines and offers up to nine hours of battery life, an intuitive touchscreen and a user-friendly operating system. Caregivers can seamlessly switch between the different therapies.
Statement by the Jury
VOCSN features impressive functionality in the smallest of spaces, making it very user-friendly and convenient to transport.


It’s pretty awful that some phones can have good battery life and capacity, but take a depressingly long time to replenish their battery. But that’s certainly not the case for the new Ulefone Power 5. Though packing a huge 13000mAh battery, the phone can be fully charged rather quickly thanks to the 5V/5A super fast charger and today we’ve got a video for you to prove it. So check it out.
As you can see in the video, the charging speed is really quite impressive. The battery climbs to 10% after just 15 minutes of charging, 45 minutes later the battery reaches 32%, 75 minutes in the battery jumps up to 52%, and after 150 mins of charging wehave 91% charged .The phone will activate trickle charging automatically when charged 90% of power, which might slow down the charging process, but will safely recover the few remaining percent. Finally, full charge is reached in just 3 hours and a half, but take note that the charging test is done with the phone turned off. According to Ulefone, aside from faster charging speed, their 5V/5A fast charge that relies on larger current is much safer compared to conventional fast charging technologies relying in larger voltage.
Gizchina News of the week
Below is a quick summary of other specs of the Ulefone Power 5 :
- 6.0-inch 18:9 all screen display with FHD+ resolution;
- Mediatek MT6763 octa-core processor (Helio P23) paired with 6GB of RAM and 64GB of internal storage;
- Sony 21MP/5MP dual rear camera setup, 13MP/5MP dual front camera setup; OIS technology; dual rear LED flash,selfie softlight
- Advanced Face ID recognition system;
- Fingerprint scanner on the side;
- Independent audio chipset;handy shortcut key on the frame;10W wireless charge
- Android 8.1 Oreo system out of the box.


So, all I want to do is display my vehicle speed digitally on an OLED, no data logging required.
I bought the Freematic Nanologger kit, but it won't even compile right "out of the box" so to speak. My intention was to just comment out anything having to do with data logging and just tell it to display the speed on my OLED. I have not been able to compile my code. It dawned on me someone has probably already done this.............True? My I get a link to the sketch?


LED Front Access Rear Projection Wide Format Slim Cube
60", 1920 x 1080 (Full HD)
60″ Full HD LED slim display wall cube
Based on the same unique LED light source technology as its widely-used Seventy Series DLP™ cubes, the new cube offers significant economies in both its space requirement and cost of ownership.
Until now, the only practical option for large format control room display in restricted spaces such as crisis suites and breakout rooms has been tiled LCD. However, LCD is not ideal for 24/7 operation and in many cases the intrusive bezel can prove distracting to operators. Mitsubishi Electric’s VS-60HS12 provides an elegant solution, offering both a near-seamless high-resolution display and true, zero-maintenance 24 hour operation in a compact footprint.
The 60” diagonal DLP rear projection cubes measure just 520 mm deep, nearly half that of Mitsubishi’s Seventy Series cubes. Being solely front access means the VS-60HS12 can be installed flush to the wall, with no rear access required. The LED projection engine employs the same patented air-cooled light source technology as Mitsubishi’s high-specification Seventy Series, and requires no maintenance over its entire lifespan of approximately 50,000 hours. Based on a 0.65” Digital Mirror Device (DMD®), the display delivers up to 660 cd/m² at 1080p resolution, enhanced by Mitsubishi’s patented Colour Space Control and Digital Graduation circuitry. The displays are also completely self-balancing, ensuring correct color balance across the wall automatically.
- 60″ Full HD
- Lifetime 60,000 hrs
- Up to 700cd/m²
- Air cooling (no liquid)
- Front access only
No burn-in and near-zero bezel design using DLP™ technology
The 0.65 DLP® chip is a reflective imaging device that is not affected by heat absorption, even when projecting a fixed pattern over a long period of time. Its durability and imaging quality are the best option among displays, especially for 24/7 operating environments.
The VS-60HS12U slim display wall cube is is equipped with three built-in sensors (one for each primary color) that use a color and brightness maintenance algorithm. The sensors continually monitor the individual red, green and blue output of each display wall cube, share the data with adjacent cubes, and adjust performance automatically to produce extremely accurate colors and brightness balance over the entire display. These features make it possible to maintain image uniformity on multi-screen configurations over long periods of operation without using external software or a computer.
Para compensar as inconsistências de cor e de brilho, em cubos de LED para Display Wall, a Mitsubishi Electric desenvolveu um circuito de balanceamento que uniformiza e combina as cores. As taxas de cada cor primária (vermelho, verde e azul) e outras misturas de cores são ajustadas para fornecer combinações de cor consistentes e uniformidade superior em configurações com múltiplas telas.
A diminução do brilho nas arestas das telas de visualização não é mais um problema graças ao inovador circuíto de gradação digital da Mitsubishi Electric. A distribuição do brilho é uniforme por todas as telas, o que garante a reprodução de imagens nítidas e vivas, de um extremo ao outro em configurações com múltiplas telas.
Learn more about this product. Request a proposal.
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