Audio-GD
Explore Audio-GD
We are glad to be selling select products from Audio GD. Audio GD is a 20 year old high end Chinese company that produces DAC's, preamps, headphone amps and other hi end 2 channel products. We were shocked at the price to performance these products offer. We will offer a 2 year warranty on our sales and service products we sell in our Georgia service facility.
R7HE MK2 (now MK3) rated Class A in Stereophile
R-1 NOS FPGA PCM/DSD DAC
$1099.00
Intro sale $999.00
The new R-1 NOS is just like the R1 but only has NOS (Non Oversampling). We feel that the NOS operation of the R1 is clearly the best sonically so we are stocking this model going forward. It is also easier to use and less confusing to most users. It is available in silver as shown or black with the new upgraded cosmetic.
Te R-1 NOS is a fully balanced discrete r2r ladder DAC using 8 group fully discrete R-2R DA converters implementing in balanced mode.
There are 4 fully discrete native DSD decoders that also work in balanced mode. The DAC handles up to 32bit / PCM384K /DSD512 asynchronous transfer using the Amanero 384 USB input. All inputs use Galavanic isolation. The DAC is a fully discrete current signal transmission design without any opamps in signal path. This new NOS design doesn't need the main clock signal to work that a typical oversampling design uses. This avoids the effect by the main clock's jitter and gives the unit a more analog vinyl like sound that most audiophiles love. The R-1 NOS digital processor uses zero delay technology that guarantee the data and clock exact synchronization for much reduced jitter. The R-1 NOS uses the latest designed discrete servo stabilized power supply to feed the digital circuits. This lowers noise and is comparable to that of a battery, but without the dry and thin sound characteristics of it. It also reduces the product's operating temperature significantly from that of the previous model. The analog circuits are still powered by a pure class-A regulated power supply for the best sound results.
The R-1 NOS has USB, coaxial and I2S over HDMI inputs
R-1 FPGA PCM/DSD DAC
Discontinued and no longer available-Replaced by the R1 NOS above
NFB-11.38
Sabre 9038 Pro DAC + Headphone amplifier & digital Preamplifier
$699.00
It has Coaxial optical and USB inputs along with a femtosecond Accusilicon 318B clock built in
There are 8 groups of double stage Power supplies built in
Amazing design at only $699.00
R8HE MK3 State of the art Resistor Ladder FPGA controlled upgradable DAC with AC regenerator built in
$2,999.00
The new 2022 R8HE MK2 upgrades the R8 MK2 and original from 2018 that received great press. A ladder DAC that is 90% as good as the best at a value price. It is even better when run thru an Audio GD preamp with ACSS buss
R-8HE MK2 features:
Thanks to the fully programmable circuits of the R-8, the firmware is upgradable to improve the sonics.
Fully balanced XLR, RCA and ACSS (CAST) connectivity
The R-8 MK2 upgrade started at the beginning of 2020, which was followed by a year of continuous audition, software and hardware fine-tuning. Using the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization each part of the circuit was refined and optimized.
The new MK2 DAC uses a new discrete servo stabilized power supply while the analog circuits are still powered by pure class-A power supply to achieve the best sound, as determined during many long listening tests.
The improvement is quite obvious compared to the previous generation.
1. Fully discrete parts are used in a truly balanced current transmission design. Four sets of fully discrete and independent DSD hardware decoders. Eight sets of fully discrete R-2R DAC modules are used to form a two-channel balanced push-pull decoder.
The R8 MK2 uses the newly designed discrete servo stabilized power supply to feed the DAC circuits. In the new DAC the noise level is now comparable to that of a battery, but without the dry and thin sound characteristics of it, and thus the product's operating temperature is significantly lower than that of the previous model. The analog circuit are still powered by a pure class-A regulated power supply for the best sonic results.
2. By listening to a turntable and studying its sound for a long time, Audio GD has successfully integrated an analog vinyl sound characteristic into the DAC. This tonal balance is optional and controlled through the front panel. This is a new feature.
3. Both the USB and HDMI inputs are equipped with opto isolators, and two sets of linear power supplies to separately supply power to the USB and HDMI modules before the isolators to prevent interference from signal sources. The USB input uses a two-way transmission isolator, which not only transmits IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor.
The USB interface itself is no longer equipped with clocks. The synchronous clock is applied to make the signal transmission more accurate and upgrade sound quality significantly over the older model. The HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.
4. The MK2 now has a display of the input signal sampling rate function.
5. The digital circuits of the whole DAC are comprised of 1 FPGA and 5 CPLDs (both programmable devices), which allow separating the different functional circuits and preventing interference. The FPGA operates using the parallel data processing mode. The parallel mode only needs one clock to transmit and process the 32-bit data of the left and right channels, which greatly improves the processing speed and is less affected by the stability of the clock.
6. Two superb Accusilicon Femto clocks provide synchronization for the whole unit, and they are applied to the playback of all data rates without PLL up-conversion. The clock management design of the new architecture makes the clock more stable, which brings a more transparent and detailed presentation.
7. DSD uses the built-in asynchronous clock to enhance timing, which obviously improves the clarity and dynamics of reproduction.
8. SPDIF supports DOP playback.
9. All digital mode settings can be changed on the front panel live.
10. A firmware upgrade port is on the rear panel so there is no need to open the cover to upgrade the firmware.
R8 MK3 FPGA controlled R2R PCM/DSD DAC
$1,999.00
Probably the best value of the Audio GD DAC's, the new R8 MK3 upgrades the original R8 & MK2 from 2018 & 2021 that received great press. A ladder DAC that is 90% as good as the best at a value price. It is even better when run thru an Audio GD preamp with ACSS buss
R-8 MK3 features:
Thanks to the fully programmable circuits of the R-8, the firmware is upgradable to improve the sonics.
Fully balanced XLR, RCA and ACSS (CAST) connectivity
The R-8 MK3 upgrade started at the beginning of 2020, which was followed by a year of continuous audition, software and hardware fine-tuning. Using the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization each part of the circuit was refined and optimized.
The new MK3 DAC uses a new discrete servo stabilized power supply while the analog circuits are still powered by pure class-A power supply to achieve the best sound, as determined during many long listening tests.
The improvement is quite obvious compared to the previous generation.
1. Fully discrete parts are used in a truly balanced current transmission design. Four sets of fully discrete and independent DSD hardware decoders. Eight sets of fully discrete R-2R DAC modules are used to form a two-channel balanced push-pull decoder.
The R8 MK3 uses the newly designed discrete servo stabilized power supply to feed the DAC circuits. In the new DAC the noise level is now comparable to that of a battery, but without the dry and thin sound characteristics of it, and thus the product's operating temperature is significantly lower than that of the previous model. The analog circuit are still powered by a pure class-A regulated power supply for the best sonic results.
2. By listening to a turntable and studying its sound for a long time, Audio GD has successfully integrated an analog vinyl sound characteristic into the DAC. This tonal balance is optional and controlled through the front panel. This is a new feature.
3. Both the USB and HDMI inputs are equipped with opto isolators, and two sets of linear power supplies to separately supply power to the USB and HDMI modules before the isolators to prevent interference from signal sources. The USB input uses a two-way transmission isolator, which not only transmits IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor.
The USB interface itself is no longer equipped with clocks. The synchronous clock is applied to make the signal transmission more accurate and upgrade sound quality significantly over the older model. The HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.
4. The MK3 now has a display of the input signal sampling rate function.
5. The digital circuits of the whole DAC are comprised of 1 FPGA and 5 CPLDs (both programmable devices), which allow separating the different functional circuits and preventing interference. The FPGA operates using the parallel data processing mode. The parallel mode only needs one clock to transmit and process the 32-bit data of the left and right channels, which greatly improves the processing speed and is less affected by the stability of the clock.
6. Two superb Accusilicon Femto clocks provide synchronization for the whole unit, and they are applied to the playback of all data rates without PLL up-conversion. The clock management design of the new architecture makes the clock more stable, which brings a more transparent and detailed presentation.
7. DSD uses the built-in asynchronous clock to enhance timing, which obviously improves the clarity and dynamics of reproduction.
8. SPDIF supports DOP playback.
9. All digital mode settings can be changed on the front panel live.
10. A firmware upgrade port is on the rear panel so there is no need to open the cover to upgrade the firmware.
R-28 NOS Balanced preamp/DAC/HP amp
1399.00
The D28 is a Fully Balanced solid state preamp with 9.5 watts per channel headphone amp and a Sabre 9038 Pro DAC. It is basically the R28 with a top of the line Sabre DAC. We continue to be shocked at this level of sonic performance along with this feature set at this cost. Comparable products sell for $2500.00 from the competition.
Stereo preamplifiers
Vacuum HE 1 XLR balanced preamplifier
$3,999.00
The Vacuum HE1 XLR is a state of the art fully balanced remote controlled preamplifier with a built in regenerative power supply. Essentially, it makes perfect new power from the wall and then feeds the preamp. This is very similar to the PS Audio Power Plant.
The class A parallel connected power supply has very high input impedance to avoid distortion through the power supply from the newly pure regenerated power supply. It has a very low output impedance so as to be very fast and is highly linear. The preamp used a tube rectifier and no opamps inside. All caps are film caps from Solen. It is a pure vacuum tube design in the power supply and signal paths using only resistors, capacitors and vacuum tubes.
Typical preamps use a volume control run thru a potentiometer. Potentiometers are not accurate and have high levels of channel imbalance. An Alps Blue Velvet volume control is rated at +/- 2 dB which leads to poor stereo imaging due to channel imbalances. The Vacuum HE1 uses a current mode volume control. The signal only passes through a resistor and then is feed to the next stage, bypassing the volume control. The final result is less than .1dB channel balance for superb imaging.
Read the entire review at: https://hometheaterhifi.com/reviews/amplifier/preamplifier/audio-gd-vacuum-he1-xlr-tube-preamplifier-review/
Rear shot with 3 sets of balanced and 2 sets of RCA inputs/Balanced and RCA outs
Vacuum HE-1 LE 10 Remote controlled tube balanced preamplifier
$2999.00
Ten tube preamp with vacuum tube rectifier, no solid state silicon elements on signal and tube power circuits
All power caps built are SOLEN film caps
Metal remote control for volume and source switching
The Vacuum HE-1 LE is essentially the top $4000.00 model above without the internal regenerative power supply. The preamp uses a tube rectifier and no opamps. All caps are film caps from Solen. It is a pure vacuum tube design in the power supply and signal paths using only resistors, capacitors and vacuum tubes.
Typical preamps use a volume control run thru a potentiometer. Potentiometers are not accurate and have high levels of channel imbalance. An Alps Blue Velvet volume control is rated at +/- 2 dB which leads to poor stereo imaging due to channel imbalances. The Vacuum HE LE uses a current mode volume control. The signal only passes through a resistor and then is fed to the next stage, bypassing the volume control. The final result is less than .1dB channel balance for superb imaging.
It is our favorite under $3000.00 preamp & competes with far more expensive competition
HE-1MK 3
Regenerative power supply Real Balanced ACSS Pure Class A Solid State Preamp
$3,299.00
The HE-1 MK3 (introduced in Sept 2023) is a fully balanced Class A preamplifier with a built in regenerative power supply. It makes perfect new power and then supplies it to the preamp. It uses all discrete analog stages without any OP amps or coupling caps in the signal path. It has a zero feedback ACSS analog current output stage. The preamp uses three R-core transformers (In total 260W ) and more than 100,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery. it has separate class A Power supplies for both the power regenerator and well as the fully discrete preamp that follows it. The HE-1 MK2 uses a four-channel 100 step digitally controlled relay-based volume control to yield superb channel balance. This greatly improves stereo imaging and and improves overall sound quality. It features 5 analog inputs. There are 2 RCA, 2 XLR and a single ACSS input. You even have ACSS output available to your amp as well as an ACSS, RCA or XLR inputs. The preamp can drive 3 power amps simultaneously.
Upgrades from original HE-1
The first generation HE-1 was released in 2015. This new MK3 version is upgraded in the following ways:
After 5 years, in 2021 Audio GD spent many months testing and auditioning this new version.
The MK2 upgrades the layout to what they call perfect Layout technology. Sound quality is improved with better detail and dynamics while also having a more analog tube-like sound. The small edge of the original is gone. There are also a functions upgrade.
1, It now has two gain modes that are user switchable to match with the different gain power amps.
2, It has a double volume control to match better with sources that have different output levels.
3, The new dual mono design allows for exact channel matching for better imaging. The boards are perfectly match before assembly to ensure consistency .
Rear shot of HE-1 MK3 preamplifier
They now come with a white display
The Remote controlled HE-1 LE is the same as the HE-1 MK2 above without the built in regenerative power supply. It is a world class fully balanced Class A stereo preamplifier. Introduced in August 2022, it uses all discrete analog stages without any OP amps or coupling caps in the signal path. It has a zero feedback ACSS analog current output stage. The preamp uses three R-core transformers (In total 260W ) and more than 100,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery. It has separate class A Power supply for the fully discrete preamp that follows it. The HE-1 LE uses a four-channel 100 step digitally controlled relay-based volume control to yield superb channel balance. This greatly improves stereo imaging and improves overall sound quality. It features 5 analog inputs. There are 2 RCA, 2 XLR and a single ACSS input. You even have ACSS output available to your amp as well as an ACSS, RCA or XLR inputs. The preamp can drive 3 power amps simultaneously.
The HE-1 LE has complete separation of left and right amplifier channels, for true dual mono design, along with separation of the power supply and the transformers. Even the 120V power input lines have extremely heavy duty shields on the thick aluminum boards. The HE-1 uses a heavyweight all-aluminum chassis to prevent the eddy current of transformers from interfering on circuit boards.
Components used are all audiophile grade including DALE resistors, WIMA caps, custom order NOVER caps from England, all audiophile grade Neutrik input & output sockets and a gold plated IEC socket. In the HE-1 LE all parts of the four channels are perfectly match before install.
Master 19 Stereo preamp with headphone amp
$1399.00
The Master 19 is a fully balanced pure class A preamp built by discrete analog stages without any OP amps or coupling caps in the signal path.
It is a superb affordable preamp with headphone amp. It uses a Non- feedback ACSS analog output stage with 8 exact matched 150W transistors ( In total 1200W )
as the output stages for implementing the large class A output power.
There arew two R-core transformers (In total 100W ) and separate power supplies for the digital control components as well as the right and left channels.
There are 4 groups pure class A Power supply to run the audio circuits.
The preamp uses over 35,000uf of audio grade NOVER capacitors to ensure ample and smooth power delivery. There are lots of hi-end grade parts and exactly matched
transistors along with OCC wire.
The volumc control is a four-channel 100 step digitally controlled relay-based control to the typical channel imbalance of other preamps. This also improves sound quality .
It will run all headphones with an exponential Volume Characteristic to match the volume with very high end headphone and speakers without change the gain mode.
It has 2 sets of RCA ins, 2 setsd of XLR is and one set of ACSS cureent inputs
The preamp output has XLR, RCA and ACSS outputs
Headphone amp output: 4pins XLR X1 / 6.3MM X1
Rear shot of Master 19
HE2 MK3 250 watt/ch amp with 30 watts pure Class A & power regenerators
1000 watt @ 2 ohms
$8,499.00 pair
Simply amazing!!
Master 2A 100 watt Class A / 150 watt A/B mono amps
600 watts at 2 ohms
$5,999.00 a pair
The Master 2A is a 100 watt pure Class A mono amplifier that will do 150 watts in Class A/B. It doubles into 4 and then again into 2 ohms to 600 watts. It produces 400 watts of pure Class A power at 2 ohms.
The Master 2A is a fully balanced design with both its gain stages and pre-driver stages working in class A. It is built with discrete analog stages without any OP Amps or coupling caps in the signal path.
The output transistor stages are super linear with 100W pure class A into 8 ohms moving to A/B up to 150 watts into 8 ohms.
There are 2 analog inputs: XLR and ACSS.
The amps use 80 ON Semiconductor transistors to support this huge output.
The capacitance of the whole machine is 260,000 uF, with two circle core and two R cores transformers and totally separate power supplies for the right channel and left channels.
There are a total of 4 high-quality class A parallel connection Power supplies to run the gain stages.
The amps use all audiophile grade components including DALE resistors, WIMA and custom order English NOVER power supply caps.
The amps use a Real Balanced ACSS Non Negative Feedback Power supply design with the patent pending Applied "Linear Fidelity" Technology unique to Audio-gd.
The amps weight 80 pounds each.
Signal to noise is greater than 110dB and gain is 26dB. Input sensitivity is 2.2v for full power thru the XLR inputs.
Sonics are even better when mated with an Audio-gd preamp thru their unique ACSS circuit.
The Master 3A is a 90 watts per channel stereo power amplifier that runs the first 50 watts in pure Class A. Both channels do 90 watts at 8 ohms, 180 watts at 4 ohms and 360 watts at 2 ohms.
The Master 3A uses a Real Balanced ACSS Non Negative Feedback design. It supports both XLR and ACSS inputs from an Audio-gd preamp. It features Applied "Linear Fidelity" Technology with a Soft Start Power Design. The amp uses 24 output transistors. The Master 3A is a fully balanced design with the the gain stages and pre-driver stages working in pure class A. The amp uses fully discretete analog stages without any opamps or coupling caps in the signal paths. There are 2 analog inputs, XLR and / ACSS.
The output stage uses a total of 24 ON Semiconductor transistors. The capacitance of the entire amp is 140,000 uF, with two circle core and two R cores transformers (Total 1600W) and totally separate power supplies for the right and left channels. There 4 groups of high-quality class A parallel connection power supplies to supply the gain stages. The amp uses all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps as well as audiophile grade input & output sockets and a gold IEC socket. The non negative feedback output drive stages uses applied "Linear Fidelity" technology that is a patent pending exclusive Audio-gd design.
S/N is>110DB
Master 10 MK2 remote controlled integrated amplifier
2024 Integrated amp of the year from Part Time Audiophile
250 watts per channel / 500 watts at 4 ohms / 1000 watts @ 2 ohms
$3,999.00
"I was so impressed with the off-the-chart value of this integrated amplifier, in fact, that I was prompted to start listing our PTA Best Value nominees for 2023. As the halfway point of the year passed by quietly a few weeks ago, I haven’t encountered anything this year that’s this amazing for the money. I might even go as far to say that the Master 10 is easily my favorite product to come out of Underwood so far. That says a lot."
The Master 10A is a fully balanced 250 watt per channel remote controlled integrated amp. It is a monster weighing in at 80 pounds and putting out 1000 watts per channel into 2 ohms. It features 2 sets of XLR balanced and 2 sets of single ended RCA inputs along with a IEC power inlet. The Master 10 uses AGD's "Linear Fidelity" technology on the output drive stages. The output drive stages have no negative feedback but can keep the distortion low and steady with an excellent linear performance. It uses a Four channel 99 step digitally controlled relay-based volume control to avoid channel imbalance and improved sound quality. The output stage uses 24 ON semiconductor transistors. The amp does 250W X2 into 8 ohms, 500 watts into 4 ohms and 1000 watts at 2 ohms. Whereas most of the competition in this price range has a signal to noise ratio in the 100-105dB range the Master 10 is 115dB. Compare this amp to the competition at $7,500.00-$10,000. We did, and were shocked.
Amazing build quality in a full dual mono design
R7HE MK2 (now MK3) rated Class A in Stereophile
R-1 NOS FPGA PCM/DSD DAC
$1099.00
Intro sale $999.00
The new R-1 NOS is just like the R1 but only has NOS (Non Oversampling). We feel that the NOS operation of the R1 is clearly the best sonically so we are stocking this model going forward. It is also easier to use and less confusing to most users. It is available in silver as shown or black with the new upgraded cosmetic.
Te R-1 NOS is a fully balanced discrete r2r ladder DAC using 8 group fully discrete R-2R DA converters implementing in balanced mode.
There are 4 fully discrete native DSD decoders that also work in balanced mode. The DAC handles up to 32bit / PCM384K /DSD512 asynchronous transfer using the Amanero 384 USB input. All inputs use Galavanic isolation. The DAC is a fully discrete current signal transmission design without any opamps in signal path. This new NOS design doesn't need the main clock signal to work that a typical oversampling design uses. This avoids the effect by the main clock's jitter and gives the unit a more analog vinyl like sound that most audiophiles love. The R-1 NOS digital processor uses zero delay technology that guarantee the data and clock exact synchronization for much reduced jitter. The R-1 NOS uses the latest designed discrete servo stabilized power supply to feed the digital circuits. This lowers noise and is comparable to that of a battery, but without the dry and thin sound characteristics of it. It also reduces the product's operating temperature significantly from that of the previous model. The analog circuits are still powered by a pure class-A regulated power supply for the best sound results.
The R-1 NOS has USB, coaxial and I2S over HDMI inputs
R-1 FPGA PCM/DSD DAC
Discontinued and no longer available-Replaced by the R1 NOS above
Sabre 9038 Pro DAC + Headphone amplifier & digital Preamplifier
$699.00
The 11.38 is a DAC with headphone amp that can also be a preamp in a digital system
It features the best Sabre DAC, the Sabre ES9038 Pro in a zero feedback design that decodes DSD64-512 , DXD, PCM 32bit / 384K It has Coaxial optical and USB inputs along with a femtosecond Accusilicon 318B clock built in
There are 8 groups of double stage Power supplies built in
Amazing design at only $699.00
R7HE MK3 State of the art Resistor Ladder DAC
FPGA controlled upgradable DAC w/regenerative power supply
$4999.00
FPGA controlled upgradable DAC w/regenerative power supply
$4999.00
Silver version
The new 2023 MK3 version replaces the MK2 that got superb press. It is the same internally with nive cosmetic sand an upgraded display. It is now also available in silver as well as black. The Inside circuitry is the same as are the sonics.
The R7HE MK3 is a dual mono fully balanced Class A reference quality PCM/DSD DAC that is dramatically underpriced for its performance level. We have heard no DAC at near this price that presently competes with it. Most competitors are selling this level of quality for well over $10,000.00. Parts quality is world class.
Overview of this spectacular DAC
Fully discrete parts are used in a truly balanced current transmission design.
-4 sets of fully discrete and independent DSD hardware decoders.
-8 sets of fully discrete R-2R DA modules to form a two-channel balanced push-pull decoder.
-2 reference Accusilicon Femto clocks provide synchronization for the DAC. Tthey are applied to the playback of all data rates without PLL up-conversion.
-32bit / 384K asynchronous Amanero USB interface synchronized with the FPGA. USB and HDMI modules are equiped with galvanic isolators and fed by two groups of independent isolated power supplies, to avoid the mutual electrical contamination between USB and HDMI.
-The DAC uses the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization for each part of the circuit. The digital circuit uses new discrete servo stabilized power supplies, while the clock and the analog circuits are still powered by pure class-A power supplies to achieve the best sound, as determined during listening tests.
-The digital circuits of the whole DAC are comprised of 1 FPGA and 7 programmable chip sets which allow separating the different functional circuits and preventing interference.
-The FPGA operates in the parallel data processing mode even at the fastest data rate, and supports firmware upgrades to improve sound quality when new and better design ideas are eventually found and implemented.
-The input signal sampling rate is displayed.
-Support of an external 10MHz clock input (default is 50 ohms, can be customized to 75 ohms ).
-All digital mode settings can be changed on the front panel live.
-A firmware upgrade port is featured on the rear panel of the machine (no need to open to take off the cover to upgrade the firmware).
In order to completely eliminate the influence of jitter in the incoming signal, the R7 HE MK3 uses an asynchronous clocking process. First it reads and stores a considerable amount of signal data into a RAM buffer. It throws away the original clock of the signal source and directly uses the high-performance built-in Accusilicons Femto clock to clock the output from the RAM buffer. Since both data and clock signals are handled by the FPGA the impact of transmission on jitter is negligeble. The jitter level is essentially the same as what is specified for the clocks. The DAC uses an asynchronous Amanero USB interface synchronized with the FPGA. It also has 4 sets of fully discrete and independent DSD hardware decoders.The power supply is servo controlled and virtually as quiet as a battery. The digital circuits are also servo controlled. It offers support for a 10MHz external digital clock.
The R7HE MK3 is a dual mono fully balanced Class A reference quality PCM/DSD DAC that is dramatically underpriced for its performance level. We have heard no DAC at near this price that presently competes with it. Most competitors are selling this level of quality for well over $10,000.00. Parts quality is world class.
This is easily the best DAC that we have ever sold. We were shocked at its performance at this price
In the November 2022 Stereophile review of the MK2 Herb Reichert said:
And he summed with:
In the November 2022 Stereophile review of the MK2 Herb Reichert said:
"Audio-GD’s R7HE MK2 is the first DAC I’ve used that played this music like an LP. I could feel human force behind every beat. I dreamed dance hall and bopped in my head. Amazingly, in my little room, the R7HE MK2 conveyed the full blues-funk mojo of gogo and jùjú without LPs. I was deeply impressed."
And he summed with:
“What is unique and special about Audio GD’s R7HE MK2 is how it renders recordings in a heightened state of naturally lit beauty and how clearly it conveys the force and drive behind recorded sounds. The R7HE delivered the dynamism and clarity of the Mola Mola Tambaqui coupled with the triodelike splendor of the Holo[1]Audio May and Denafrips’s Terminator Plus. In my book, that establishes Mr. He Qinghua as a genuine digital wizard and earns my highest recommendation.”
The DAC uses a regenerative power supply, (similar to a PS Power Plant), to make perfect brand new power to supply it.
Read the entire review here: https://www.stereophile.com/content/gramophone-dreams-66-audio-gd-r7he-mk2-da-processor
Read the entire review here: https://www.stereophile.com/content/gramophone-dreams-66-audio-gd-r7he-mk2-da-processor
Overview of this spectacular DAC
Fully discrete parts are used in a truly balanced current transmission design.
-4 sets of fully discrete and independent DSD hardware decoders.
-8 sets of fully discrete R-2R DA modules to form a two-channel balanced push-pull decoder.
-2 reference Accusilicon Femto clocks provide synchronization for the DAC. Tthey are applied to the playback of all data rates without PLL up-conversion.
-32bit / 384K asynchronous Amanero USB interface synchronized with the FPGA. USB and HDMI modules are equiped with galvanic isolators and fed by two groups of independent isolated power supplies, to avoid the mutual electrical contamination between USB and HDMI.
-The DAC uses the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization for each part of the circuit. The digital circuit uses new discrete servo stabilized power supplies, while the clock and the analog circuits are still powered by pure class-A power supplies to achieve the best sound, as determined during listening tests.
-The digital circuits of the whole DAC are comprised of 1 FPGA and 7 programmable chip sets which allow separating the different functional circuits and preventing interference.
-The FPGA operates in the parallel data processing mode even at the fastest data rate, and supports firmware upgrades to improve sound quality when new and better design ideas are eventually found and implemented.
-The input signal sampling rate is displayed.
-Support of an external 10MHz clock input (default is 50 ohms, can be customized to 75 ohms ).
-All digital mode settings can be changed on the front panel live.
-A firmware upgrade port is featured on the rear panel of the machine (no need to open to take off the cover to upgrade the firmware).
In order to completely eliminate the influence of jitter in the incoming signal, the R7 HE MK3 uses an asynchronous clocking process. First it reads and stores a considerable amount of signal data into a RAM buffer. It throws away the original clock of the signal source and directly uses the high-performance built-in Accusilicons Femto clock to clock the output from the RAM buffer. Since both data and clock signals are handled by the FPGA the impact of transmission on jitter is negligeble. The jitter level is essentially the same as what is specified for the clocks. The DAC uses an asynchronous Amanero USB interface synchronized with the FPGA. It also has 4 sets of fully discrete and independent DSD hardware decoders.The power supply is servo controlled and virtually as quiet as a battery. The digital circuits are also servo controlled. It offers support for a 10MHz external digital clock.
Black version
Dual mono Class A fully balanced architecture
R8HE MK3 State of the art Resistor Ladder FPGA controlled upgradable DAC with AC regenerator built in
$2,999.00
Available in Black or Silver
Take the big selling R8 MK2 DAC shown below at $1999.00 and add a full power regenerator and you have the R8HE MK2 at $2,999.00
The DAC uses a regenerative power supply, (similar to a PS Power Plant), to make perfect brand new power to supply it.
Take the big selling R8 MK2 DAC shown below at $1999.00 and add a full power regenerator and you have the R8HE MK2 at $2,999.00
The DAC uses a regenerative power supply, (similar to a PS Power Plant), to make perfect brand new power to supply it.
The new 2022 R8HE MK2 upgrades the R8 MK2 and original from 2018 that received great press. A ladder DAC that is 90% as good as the best at a value price. It is even better when run thru an Audio GD preamp with ACSS buss
At under $3,000 this is easily the DAC to beat. It clearly outperformed the PS Direct Stream that we compared it to.
R-8HE MK2 features:
Thanks to the fully programmable circuits of the R-8, the firmware is upgradable to improve the sonics.
Fully balanced XLR, RCA and ACSS (CAST) connectivity
The R-8 MK2 upgrade started at the beginning of 2020, which was followed by a year of continuous audition, software and hardware fine-tuning. Using the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization each part of the circuit was refined and optimized.
The new MK2 DAC uses a new discrete servo stabilized power supply while the analog circuits are still powered by pure class-A power supply to achieve the best sound, as determined during many long listening tests.
The improvement is quite obvious compared to the previous generation.
1. Fully discrete parts are used in a truly balanced current transmission design. Four sets of fully discrete and independent DSD hardware decoders. Eight sets of fully discrete R-2R DAC modules are used to form a two-channel balanced push-pull decoder.
The R8 MK2 uses the newly designed discrete servo stabilized power supply to feed the DAC circuits. In the new DAC the noise level is now comparable to that of a battery, but without the dry and thin sound characteristics of it, and thus the product's operating temperature is significantly lower than that of the previous model. The analog circuit are still powered by a pure class-A regulated power supply for the best sonic results.
2. By listening to a turntable and studying its sound for a long time, Audio GD has successfully integrated an analog vinyl sound characteristic into the DAC. This tonal balance is optional and controlled through the front panel. This is a new feature.
3. Both the USB and HDMI inputs are equipped with opto isolators, and two sets of linear power supplies to separately supply power to the USB and HDMI modules before the isolators to prevent interference from signal sources. The USB input uses a two-way transmission isolator, which not only transmits IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor.
The USB interface itself is no longer equipped with clocks. The synchronous clock is applied to make the signal transmission more accurate and upgrade sound quality significantly over the older model. The HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.
4. The MK2 now has a display of the input signal sampling rate function.
5. The digital circuits of the whole DAC are comprised of 1 FPGA and 5 CPLDs (both programmable devices), which allow separating the different functional circuits and preventing interference. The FPGA operates using the parallel data processing mode. The parallel mode only needs one clock to transmit and process the 32-bit data of the left and right channels, which greatly improves the processing speed and is less affected by the stability of the clock.
6. Two superb Accusilicon Femto clocks provide synchronization for the whole unit, and they are applied to the playback of all data rates without PLL up-conversion. The clock management design of the new architecture makes the clock more stable, which brings a more transparent and detailed presentation.
7. DSD uses the built-in asynchronous clock to enhance timing, which obviously improves the clarity and dynamics of reproduction.
8. SPDIF supports DOP playback.
9. All digital mode settings can be changed on the front panel live.
10. A firmware upgrade port is on the rear panel so there is no need to open the cover to upgrade the firmware.
R8 MK3 FPGA controlled R2R PCM/DSD DAC
$1,999.00
Available in Black or Silver
Probably the best value of the Audio GD DAC's, the new R8 MK3 upgrades the original R8 & MK2 from 2018 & 2021 that received great press. A ladder DAC that is 90% as good as the best at a value price. It is even better when run thru an Audio GD preamp with ACSS buss
At under $2,000 this is easily the DAC to beat. It outperformed the $6000.00 PS Direct Stream that we compared it to.
R-8 MK3 features:
Thanks to the fully programmable circuits of the R-8, the firmware is upgradable to improve the sonics.
Fully balanced XLR, RCA and ACSS (CAST) connectivity
The R-8 MK3 upgrade started at the beginning of 2020, which was followed by a year of continuous audition, software and hardware fine-tuning. Using the latest discrete servo stabilized power supply, whose performance is comparable to batteries after more than a year of calibration and optimization each part of the circuit was refined and optimized.
The new MK3 DAC uses a new discrete servo stabilized power supply while the analog circuits are still powered by pure class-A power supply to achieve the best sound, as determined during many long listening tests.
The improvement is quite obvious compared to the previous generation.
1. Fully discrete parts are used in a truly balanced current transmission design. Four sets of fully discrete and independent DSD hardware decoders. Eight sets of fully discrete R-2R DAC modules are used to form a two-channel balanced push-pull decoder.
The R8 MK3 uses the newly designed discrete servo stabilized power supply to feed the DAC circuits. In the new DAC the noise level is now comparable to that of a battery, but without the dry and thin sound characteristics of it, and thus the product's operating temperature is significantly lower than that of the previous model. The analog circuit are still powered by a pure class-A regulated power supply for the best sonic results.
2. By listening to a turntable and studying its sound for a long time, Audio GD has successfully integrated an analog vinyl sound characteristic into the DAC. This tonal balance is optional and controlled through the front panel. This is a new feature.
3. Both the USB and HDMI inputs are equipped with opto isolators, and two sets of linear power supplies to separately supply power to the USB and HDMI modules before the isolators to prevent interference from signal sources. The USB input uses a two-way transmission isolator, which not only transmits IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor.
The USB interface itself is no longer equipped with clocks. The synchronous clock is applied to make the signal transmission more accurate and upgrade sound quality significantly over the older model. The HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.
4. The MK3 now has a display of the input signal sampling rate function.
5. The digital circuits of the whole DAC are comprised of 1 FPGA and 5 CPLDs (both programmable devices), which allow separating the different functional circuits and preventing interference. The FPGA operates using the parallel data processing mode. The parallel mode only needs one clock to transmit and process the 32-bit data of the left and right channels, which greatly improves the processing speed and is less affected by the stability of the clock.
6. Two superb Accusilicon Femto clocks provide synchronization for the whole unit, and they are applied to the playback of all data rates without PLL up-conversion. The clock management design of the new architecture makes the clock more stable, which brings a more transparent and detailed presentation.
7. DSD uses the built-in asynchronous clock to enhance timing, which obviously improves the clarity and dynamics of reproduction.
8. SPDIF supports DOP playback.
9. All digital mode settings can be changed on the front panel live.
10. A firmware upgrade port is on the rear panel so there is no need to open the cover to upgrade the firmware.
Rear shot showing 5 inputs and 3 sets of outputs
R-28 NOS Balanced preamp/DAC/HP amp
1399.00
The R28 NOS is the same as the R28 above without the upsampling features of the standard R28. Since most users liked the R28 in NOS mode the best this is a better way to go for less money
The R28 NOS has a Fully Balance Discrete Headphone, DAC amp and balanced Preamp All In One chassis. is uses 8 group fully discrete
R-2R DA converters (4 pcs DA-8 board) implementing balanced mode. There are 4 fully discrete native DSD decoders that work in balanced mode.
32bit / PCM384K /DSD512 asynchronous transfer using the Amanero 384 USB receiving chip.
All inputs are galvanically isolated for each other for lower noise
It uses a fully discrete current signal transmission design with No OP Amps in signal path.
The R28 NOS features a real balanced headphone amp with max output power of 9.5 watts that can drive any headphone easily.
The unit supports firmware updates to improve on sound quality.
All digital process mode settings are accessible by buttons on front so there is No need to open the chassis
The R28 NOS comes with a plastic remote control. A metal remote adds $50.00
Build quality as seen below is superb
The R28 NOS has a Fully Balance Discrete Headphone, DAC amp and balanced Preamp All In One chassis. is uses 8 group fully discrete
R-2R DA converters (4 pcs DA-8 board) implementing balanced mode. There are 4 fully discrete native DSD decoders that work in balanced mode.
32bit / PCM384K /DSD512 asynchronous transfer using the Amanero 384 USB receiving chip.
All inputs are galvanically isolated for each other for lower noise
It uses a fully discrete current signal transmission design with No OP Amps in signal path.
The R28 NOS features a real balanced headphone amp with max output power of 9.5 watts that can drive any headphone easily.
The unit supports firmware updates to improve on sound quality.
All digital process mode settings are accessible by buttons on front so there is No need to open the chassis
The R28 NOS comes with a plastic remote control. A metal remote adds $50.00
Build quality as seen below is superb
Above is rear shot of R28 NOS
D28.38 Balanced remote preamp with Sabre 9038 Pro DAC & 9.5wpc headphone amp
$1,399.00
$1,399.00
The D28 is a Fully Balanced solid state preamp with 9.5 watts per channel headphone amp and a Sabre 9038 Pro DAC. It is basically the R28 with a top of the line Sabre DAC. We continue to be shocked at this level of sonic performance along with this feature set at this cost. Comparable products sell for $2500.00 from the competition.
The D28 features the best 9038 Pro Sabre DAC. The DAC uses a 90/98 MHz Accusilicon 318B femto clock to provide ultra low jitter.
Fully balanced non-feedback design built by discrete transistors
Total of 10-groups of PSU are used to purify the power supply
Total of 7-groups of PSU combined into double stages Power Supplies for the digital section
The ES9038Pro is powered separately by two groups of ultra low noise transistors that serve as the power supply
The analog amp power supply is run by discrete linear ower supplies.
The volume control is a resistor ladder with four channels that are digitally controlled. There are 100 steps and it is relay-based for a channel balance of 0.05% to avoid channel imbalance.
Large R-core transformers and Hi-end grade parts are used throughout.
There is a High and Low gain position to drive 80-115dB sensitivity headphones
All digital process mode settings are user adjustable and accessible by buttons on the front.
There are 4 digital inputs: USB / Optical / Coaxial RCA / I2S. There are 2 analog inputs: XLR / RCA
(The RCA input can be converted to a balanced output natively without an extra converter)
Ourputs are XLR, RCA and ACSS
Headphone output is both 4 pin XLR balanced and 1/4" (6.3MM) Single ended
The D28 headphone amp has two gain modes, 12DB in the low gain position to drive higher efficiency headphones at over 95dB sensitivity, and 22DB on high gain with the full 9.5 watts to drive any lower efficiency phones such as the HifiMan HE6 at 85dB efficiency.
The custom internal software that runs the unit is upgradable to improve sound quality in the future.
The upgraded metal remote control adds $60.00.
Parts and build quality are superb
DI-24 HE
Re-clocker with regenerative power supply
Re-clocker with regenerative power supply
Stereo preamplifiers
Vacuum HE 1 XLR balanced preamplifier
$3,999.00
The Vacuum HE1 XLR is a state of the art fully balanced remote controlled preamplifier with a built in regenerative power supply. Essentially, it makes perfect new power from the wall and then feeds the preamp. This is very similar to the PS Audio Power Plant.
We have compared this preamp to units selling for 10 times its cost and it was as good or better.
The class A parallel connected power supply has very high input impedance to avoid distortion through the power supply from the newly pure regenerated power supply. It has a very low output impedance so as to be very fast and is highly linear. The preamp used a tube rectifier and no opamps inside. All caps are film caps from Solen. It is a pure vacuum tube design in the power supply and signal paths using only resistors, capacitors and vacuum tubes.
Audio-gd Vacuum HE1 XLR Tube Preamplifier Features:
- Fully balanced circuitry throughout
- Built-in regenerative power supply
- 10 tube complement
- Vacuum Tube Rectifier without silicon elements on signal and tube power circuitry
- All power capacitors sourced from Solen
- Remote control for volume and source switching
Typical preamps use a volume control run thru a potentiometer. Potentiometers are not accurate and have high levels of channel imbalance. An Alps Blue Velvet volume control is rated at +/- 2 dB which leads to poor stereo imaging due to channel imbalances. The Vacuum HE1 uses a current mode volume control. The signal only passes through a resistor and then is feed to the next stage, bypassing the volume control. The final result is less than .1dB channel balance for superb imaging.
The preamp uses Russian aviation quality tubes. They are Six 6H2N-EB tubes and Four 6U4N-EB tubes.
In the Hometheater hifi review Glenn Young said:
"The Audio-gd Vacuum HE1 XLR tube preamplifier is the best sounding preamplifier that I’ve ever heard." "Considering its bargain price, I recommend it very strongly."
In the Hometheater hifi review Glenn Young said:
"The Audio-gd Vacuum HE1 XLR tube preamplifier is the best sounding preamplifier that I’ve ever heard." "Considering its bargain price, I recommend it very strongly."
Read the entire review at: https://hometheaterhifi.com/reviews/amplifier/preamplifier/audio-gd-vacuum-he1-xlr-tube-preamplifier-review/
All preamps are burned in for 100 hours before they leave the factory and we recommend another 100 hours for full burn-in.
S/N is >96DB (2V input，2VRMS output , Unweighted )
Output impedance is less than 300 ohms and gain is 11dB.
The balanced input impedance of Vacuum HE-1 XLR is 94K and the unbalanced input is 47K
The balanced input impedance of Vacuum HE-1 XLR is 94K and the unbalanced input is 47K
We will stock the balanced version with 10 tubes but we can special order the single ended RCA only 8 tube version upon request.
Current versions ship with a blue display but wew can special order red if that is preferrd. Allow 6-8 weeks for a special order. Remote function
17.9" w x 18.75" d x 5.2" h, with feet
Current versions ship with a blue display but wew can special order red if that is preferrd. Allow 6-8 weeks for a special order. Remote function
17.9" w x 18.75" d x 5.2" h, with feet
Rear shot with 3 sets of balanced and 2 sets of RCA inputs/Balanced and RCA outs
Build quality is amazing
Vacuum HE-1 LE 10 Remote controlled tube balanced preamplifier
$2999.00
They come standard with a white display only now
Ten tube preamp with vacuum tube rectifier, no solid state silicon elements on signal and tube power circuits
All power caps built are SOLEN film caps
Metal remote control for volume and source switching
The Vacuum HE-1 LE is essentially the top $4000.00 model above without the internal regenerative power supply. The preamp uses a tube rectifier and no opamps. All caps are film caps from Solen. It is a pure vacuum tube design in the power supply and signal paths using only resistors, capacitors and vacuum tubes.
Typical preamps use a volume control run thru a potentiometer. Potentiometers are not accurate and have high levels of channel imbalance. An Alps Blue Velvet volume control is rated at +/- 2 dB which leads to poor stereo imaging due to channel imbalances. The Vacuum HE LE uses a current mode volume control. The signal only passes through a resistor and then is fed to the next stage, bypassing the volume control. The final result is less than .1dB channel balance for superb imaging.
The preamp uses Russian aviation quality tubes. They are Six 6H2N-EB tubes and Four 6U4N-EB tubes.
In the Hometheater hifi review of the model with power regenerator Glenn Young said:
"The Audio-gd Vacuum HE1 XLR tube preamplifier is the best sounding preamplifier that I’ve ever heard." "Considering its bargain price, I recommend it very strongly."
In the Hometheater hifi review of the model with power regenerator Glenn Young said:
"The Audio-gd Vacuum HE1 XLR tube preamplifier is the best sounding preamplifier that I’ve ever heard." "Considering its bargain price, I recommend it very strongly."
It is our favorite under $3000.00 preamp & competes with far more expensive competition
Features:
- Fully balanced circuitry throughout
- 10 tube complement
- Vacuum Tube Rectifier without silicon elements on signal and tube power circuitry
- All power capacitors sourced from Solen
- Remote control for volume and source switching
- XLR and RCA outputs
- Adjustable sonics by swapping 2 internal tubes
- 11dB gain
Below is an interior photo. Notice the amazing build quality
HE-1MK 3
Regenerative power supply Real Balanced ACSS Pure Class A Solid State Preamp
$3,299.00
In the secrets review they said:
"The Audio-gd HE-1 preamplifier is one of the three best preamplifiers I’ve ever heard. It creates an acoustic space like no other component. Despite the spatial goodness, the HE-1 avoids coloring the sound. Not to be missed!"
The HE-1 MK3 (introduced in Sept 2023) is a fully balanced Class A preamplifier with a built in regenerative power supply. It makes perfect new power and then supplies it to the preamp. It uses all discrete analog stages without any OP amps or coupling caps in the signal path. It has a zero feedback ACSS analog current output stage. The preamp uses three R-core transformers (In total 260W ) and more than 100,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery. it has separate class A Power supplies for both the power regenerator and well as the fully discrete preamp that follows it. The HE-1 MK2 uses a four-channel 100 step digitally controlled relay-based volume control to yield superb channel balance. This greatly improves stereo imaging and and improves overall sound quality. It features 5 analog inputs. There are 2 RCA, 2 XLR and a single ACSS input. You even have ACSS output available to your amp as well as an ACSS, RCA or XLR inputs. The preamp can drive 3 power amps simultaneously.
Upgrades from original HE-1
The first generation HE-1 was released in 2015. This new MK3 version is upgraded in the following ways:
After 5 years, in 2021 Audio GD spent many months testing and auditioning this new version.
The MK2 upgrades the layout to what they call perfect Layout technology. Sound quality is improved with better detail and dynamics while also having a more analog tube-like sound. The small edge of the original is gone. There are also a functions upgrade.
1, It now has two gain modes that are user switchable to match with the different gain power amps.
2, It has a double volume control to match better with sources that have different output levels.
3, The new dual mono design allows for exact channel matching for better imaging. The boards are perfectly match before assembly to ensure consistency .
Reviews on the original were superb comparing the preamp to others selling for 3-4 times its price.
Parts and build quality as shown above are world class
The HE-1 MK3 has complete separation of left and right amplifier channels, for true dual mono design, along with separation of the regenerative drivers and the transformers. Even the 120V power input lines have extremely heavy duty shields on the thick aluminum boards. The HE-1 uses a heavyweight all-aluminum chassis to prevent the eddy current of transformers from interfering on circuit boards.
Components used are all audiophile grade including DALE resistors, WIMA caps, custom order NOVER caps from England, all audiophile grade Neutrik input & output sockets and a gold plated IEC socket. In the HE-1 all parts of the four channels are perfectly match before install.
Components used are all audiophile grade including DALE resistors, WIMA caps, custom order NOVER caps from England, all audiophile grade Neutrik input & output sockets and a gold plated IEC socket. In the HE-1 all parts of the four channels are perfectly match before install.
Rear shot of HE-1 MK3 preamplifier
HE-1 LE
Real Balanced ACSS Pure Class A Solid State Preamp
$2,799.00
Real Balanced ACSS Pure Class A Solid State Preamp
$2,799.00
They now come with a white display
The Remote controlled HE-1 LE is the same as the HE-1 MK2 above without the built in regenerative power supply. It is a world class fully balanced Class A stereo preamplifier. Introduced in August 2022, it uses all discrete analog stages without any OP amps or coupling caps in the signal path. It has a zero feedback ACSS analog current output stage. The preamp uses three R-core transformers (In total 260W ) and more than 100,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery. It has separate class A Power supply for the fully discrete preamp that follows it. The HE-1 LE uses a four-channel 100 step digitally controlled relay-based volume control to yield superb channel balance. This greatly improves stereo imaging and improves overall sound quality. It features 5 analog inputs. There are 2 RCA, 2 XLR and a single ACSS input. You even have ACSS output available to your amp as well as an ACSS, RCA or XLR inputs. The preamp can drive 3 power amps simultaneously.
The HE-1 LE has complete separation of left and right amplifier channels, for true dual mono design, along with separation of the power supply and the transformers. Even the 120V power input lines have extremely heavy duty shields on the thick aluminum boards. The HE-1 uses a heavyweight all-aluminum chassis to prevent the eddy current of transformers from interfering on circuit boards.
Components used are all audiophile grade including DALE resistors, WIMA caps, custom order NOVER caps from England, all audiophile grade Neutrik input & output sockets and a gold plated IEC socket. In the HE-1 LE all parts of the four channels are perfectly match before install.
Rear shot of HE-1 LE
Parts and build quality as shown above are world class
Parts and build quality as shown above are world class
Master 19 Stereo preamp with headphone amp
$1399.00
The Master 19 is a fully balanced pure class A preamp built by discrete analog stages without any OP amps or coupling caps in the signal path.
It is a superb affordable preamp with headphone amp. It uses a Non- feedback ACSS analog output stage with 8 exact matched 150W transistors ( In total 1200W )
as the output stages for implementing the large class A output power.
There arew two R-core transformers (In total 100W ) and separate power supplies for the digital control components as well as the right and left channels.
There are 4 groups pure class A Power supply to run the audio circuits.
The preamp uses over 35,000uf of audio grade NOVER capacitors to ensure ample and smooth power delivery. There are lots of hi-end grade parts and exactly matched
transistors along with OCC wire.
The volumc control is a four-channel 100 step digitally controlled relay-based control to the typical channel imbalance of other preamps. This also improves sound quality .
It will run all headphones with an exponential Volume Characteristic to match the volume with very high end headphone and speakers without change the gain mode.
It has 2 sets of RCA ins, 2 setsd of XLR is and one set of ACSS cureent inputs
The preamp output has XLR, RCA and ACSS outputs
Headphone amp output: 4pins XLR X1 / 6.3MM X1
Rear shot of Master 19
Inside shot of Master 19
Power amplifiers
HE2 MK3 250 watt/ch amp with 30 watts pure Class A & power regenerators
1000 watt @ 2 ohms
$8,499.00 pair
Simply amazing!!
These are the best solid state amps that we sell at multiples of their cost.
Compare these amps to competition at $20-30,000.00!!
Compare these amps to competition at $20-30,000.00!!
Built in Regenerate power supply's for the gain section with 4 separate chassis
30W pure class A, 250W class A/B at 8 ohm each channel
500 watts @ 4 ohms, 1000 watts @ 2 ohms
Supports XLR and ACSS inputs
Uses Real balanced ACSS non negative feedback power amplifier
"Linear Fidelity" technology non negative feedback output stages
Soft start power design
80 pcs ON semi (Motorola) output transistors
The HE2 MK3 is an upgrade from the MK2. It now includes the regenerative supply inside of the amp. It is a fully balanced design. The gain stages and pre-driver stages work in pure class A. The amp is built with discrete analog stages without any OP amps or coupling caps in the signal path.
The output transistor stages are super linear and Class A to 30 watts. The amp sounds like a pure class A design but without the high heat of a pure full class A design .
There are 2 analog inputs: XLR or ACSS to run with Audio GD solid state preamps
Each channel uses 80 Motorola (ON Semiconductor) output transistors. Each one is rated at 15A/230 Watts. Each channel runs at 30 Watts in pure class A and 250 Watts class A/B output at 8 ohms. The amp doubles into 4 ohms and then doubles again to 1000 watts at 2 ohms.
The amps has 260,000 uF of capacitance with 6 transformers for over Over 2000 Watt capability. There are separate power supplies for the right channel and left channels.
There are a total of 8 high-quality class A parallel connection Power supplies used.
The amps use all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps, audiophile grade input & output sockets and gold IEC socket.
Weight: 187 pounds shipped
30W pure class A, 250W class A/B at 8 ohm each channel
500 watts @ 4 ohms, 1000 watts @ 2 ohms
Supports XLR and ACSS inputs
Uses Real balanced ACSS non negative feedback power amplifier
"Linear Fidelity" technology non negative feedback output stages
Soft start power design
80 pcs ON semi (Motorola) output transistors
The HE2 MK3 is an upgrade from the MK2. It now includes the regenerative supply inside of the amp. It is a fully balanced design. The gain stages and pre-driver stages work in pure class A. The amp is built with discrete analog stages without any OP amps or coupling caps in the signal path.
The output transistor stages are super linear and Class A to 30 watts. The amp sounds like a pure class A design but without the high heat of a pure full class A design .
There are 2 analog inputs: XLR or ACSS to run with Audio GD solid state preamps
Each channel uses 80 Motorola (ON Semiconductor) output transistors. Each one is rated at 15A/230 Watts. Each channel runs at 30 Watts in pure class A and 250 Watts class A/B output at 8 ohms. The amp doubles into 4 ohms and then doubles again to 1000 watts at 2 ohms.
The amps has 260,000 uF of capacitance with 6 transformers for over Over 2000 Watt capability. There are separate power supplies for the right channel and left channels.
There are a total of 8 high-quality class A parallel connection Power supplies used.
The amps use all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps, audiophile grade input & output sockets and gold IEC socket.
Weight: 187 pounds shipped
Master 2A 100 watt Class A / 150 watt A/B mono amps
600 watts at 2 ohms
$5,999.00 a pair
The Master 2A is a 100 watt pure Class A mono amplifier that will do 150 watts in Class A/B. It doubles into 4 and then again into 2 ohms to 600 watts. It produces 400 watts of pure Class A power at 2 ohms.
The Master 2A is a fully balanced design with both its gain stages and pre-driver stages working in class A. It is built with discrete analog stages without any OP Amps or coupling caps in the signal path.
The output transistor stages are super linear with 100W pure class A into 8 ohms moving to A/B up to 150 watts into 8 ohms.
There are 2 analog inputs: XLR and ACSS.
The amps use 80 ON Semiconductor transistors to support this huge output.
The capacitance of the whole machine is 260,000 uF, with two circle core and two R cores transformers and totally separate power supplies for the right channel and left channels.
There are a total of 4 high-quality class A parallel connection Power supplies to run the gain stages.
The amps use all audiophile grade components including DALE resistors, WIMA and custom order English NOVER power supply caps.
The amps use a Real Balanced ACSS Non Negative Feedback Power supply design with the patent pending Applied "Linear Fidelity" Technology unique to Audio-gd.
The amps weight 80 pounds each.
Signal to noise is greater than 110dB and gain is 26dB. Input sensitivity is 2.2v for full power thru the XLR inputs.
Sonics are even better when mated with an Audio-gd preamp thru their unique ACSS circuit.
Compare this amp to competitors selling for $25,000 and it is right there.
They are a steal for under $10,000.00 for the pair.
They are a steal for under $10,000.00 for the pair.
Master 3A Class 50 watt Class A/ 90 watt AB power amplifier
$3,799.00
$3,799.00
The Master 3A is a 90 watts per channel stereo power amplifier that runs the first 50 watts in pure Class A. Both channels do 90 watts at 8 ohms, 180 watts at 4 ohms and 360 watts at 2 ohms.
Compare this amp to competitive models selling in the $5000.00-$7500.00 range and it holds its own.
The Master 3A uses a Real Balanced ACSS Non Negative Feedback design. It supports both XLR and ACSS inputs from an Audio-gd preamp. It features Applied "Linear Fidelity" Technology with a Soft Start Power Design. The amp uses 24 output transistors. The Master 3A is a fully balanced design with the the gain stages and pre-driver stages working in pure class A. The amp uses fully discretete analog stages without any opamps or coupling caps in the signal paths. There are 2 analog inputs, XLR and / ACSS.
The output stage uses a total of 24 ON Semiconductor transistors. The capacitance of the entire amp is 140,000 uF, with two circle core and two R cores transformers (Total 1600W) and totally separate power supplies for the right and left channels. There 4 groups of high-quality class A parallel connection power supplies to supply the gain stages. The amp uses all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps as well as audiophile grade input & output sockets and a gold IEC socket. The non negative feedback output drive stages uses applied "Linear Fidelity" technology that is a patent pending exclusive Audio-gd design.
S/N is>110DB
Gain is 26dB
Input impedance is 94K ohm @ XLR
input sensitivity is 1.4V RMS @ XLR
Weight is 88 pounds
Size is 18.9"W x 17.3"(D) x 7.5" (H) (MM, Fully aluminium )
Weight is 88 pounds
Size is 18.9"W x 17.3"(D) x 7.5" (H) (MM, Fully aluminium )
Overbuilt dual mono design with world class parts
Master 10 MK2 remote controlled integrated amplifier
2024 Integrated amp of the year from Part Time Audiophile
250 watts per channel / 500 watts at 4 ohms / 1000 watts @ 2 ohms
$3,999.00
"I was so impressed with the off-the-chart value of this integrated amplifier, in fact, that I was prompted to start listing our PTA Best Value nominees for 2023. As the halfway point of the year passed by quietly a few weeks ago, I haven’t encountered anything this year that’s this amazing for the money. I might even go as far to say that the Master 10 is easily my favorite product to come out of Underwood so far. That says a lot."
The Master 10A is a fully balanced 250 watt per channel remote controlled integrated amp. It is a monster weighing in at 80 pounds and putting out 1000 watts per channel into 2 ohms. It features 2 sets of XLR balanced and 2 sets of single ended RCA inputs along with a IEC power inlet. The Master 10 uses AGD's "Linear Fidelity" technology on the output drive stages. The output drive stages have no negative feedback but can keep the distortion low and steady with an excellent linear performance. It uses a Four channel 99 step digitally controlled relay-based volume control to avoid channel imbalance and improved sound quality. The output stage uses 24 ON semiconductor transistors. The amp does 250W X2 into 8 ohms, 500 watts into 4 ohms and 1000 watts at 2 ohms. Whereas most of the competition in this price range has a signal to noise ratio in the 100-105dB range the Master 10 is 115dB. Compare this amp to the competition at $7,500.00-$10,000. We did, and were shocked.
- Fully balanced design, the gain stages and pre-driver stages working on class A built by discrete analog stages without any OP amps or coupling caps in the signal path.
- The output transistors stages work in high idle current state. The Diamond Cross output stage design avoids “switch distortion” as well as class A amps
- Non- feedback ACSS analog amps .
- The capacitance of the whole machine reaches as high as 140,000 uF, with two 750W circle core and two R cores transformers (Total 1500W) and separate power supplies for the right channel and left channels.
- A total of 4 groups of high-quality class A parallel connection Power supply gain stages. To achieve a high S/N, the control circuit is powered with separate regulators.
- Four channel 99 steps digitally controlled relay-based volume control avoids channel imbalance and improves sound quality.
- Applies all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps, all audiophile grade input & output sockets and gold IEC socket.
- Inputs: 5 analog inputs: RCA x2, XLR x2, ACSS x1
Amazing build quality in a full dual mono design