The Audio GD S19 is a digital-to-analog converter (DAC) and headphone amplifier designed by Audio GD, a company known for its high-quality audio equipment. Here are some key features and information about the Audio GD S19:Dedicated Discrete R2R DACUser setting between NOS,2x,4x and 8x OversamplingBuilt in 4 PCs 3072KHz support R-2R DA M1 modules32bit / 384K Amanero combo384Supports up to 384KHz /32Bit at USBSupports up to 192KHz /24Bit at SPDIF

I am the original owner, and bought it new last year. I have too many amps, and am thinning the collection.Standard remote control included. From the website:The R28 NOS is a Fully Balanced solid state preamp with 9.5 watts per channel headphone amp and a resistor ladder DAC. We continue to be shocked at this level of sonic performance along with this feature set at this cost. Comparable products sell for $3000.00-$4000.00 range from the competition. The preamp or DAC alone is worth he price of the entire product. DAC’s of this quality typically sell for over $3000.00. The R28 features 8 fully discrete R2R DAC modules to combine into a real balanced push/pull digital decoder as well as 4 fully discrete real balanced DSD native decoders. The DAC uses two 90/98 MHz Accusilicon 318B femto clocks to provide ultra low jitter. The Amanero USB input supports 32bit / PCM384K PCM and up to DSD 512 asynchronous transfer. Clocking is done by a custom programmed FPGA. The whole digital circuit is built around one custom programmed FPGA and 5 CPLD programmable chip sets to separate the different circuits for avoid any interference in the data process in parallel mode. The R28 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. All digital process mode settings are accessible by buttons on the front. The analog output stage is superb and has a tremendous effect on any DAC’s sound quality. After the D/A conversion by the R2R D/A modules the analog signal is run by fully discrete matched-transistor output stages. These high speed special ACSS output stages are zero-feedback and a current driven design as opposed to the voltage design of most other DAC’s. They are Special because almost all other designs need to convert the signal multiple times from and to current or voltage, resulting in less detail and a less defined sound stage. The Output stage in the R28 has 4 pairs of 15W transistors to offer tremendous output capability. This Diamond Differential design avoids switch distortion. It works in full Class A mode but doesn’t draw large idle current. This balanced drive design lowers noise and distortion and improves the sound stage presentation and transparency.

I am the original owner, and bought it new last year. I have too many amps, and am thinning the collection.Standard remote control included. From the website:The R28 NOS is a Fully Balanced solid state preamp with 9.5 watts per channel headphone amp and a resistor ladder DAC. We continue to be shocked at this level of sonic performance along with this feature set at this cost. Comparable products sell for $3000.00-$4000.00 range from the competition. The preamp or DAC alone is worth he price of the entire product. DAC’s of this quality typically sell for over $3000.00. The R28 features 8 fully discrete R2R DAC modules to combine into a real balanced push/pull digital decoder as well as 4 fully discrete real balanced DSD native decoders. The DAC uses two 90/98 MHz Accusilicon 318B femto clocks to provide ultra low jitter. The Amanero USB input supports 32bit / PCM384K PCM and up to DSD 512 asynchronous transfer. Clocking is done by a custom programmed FPGA. The whole digital circuit is built around one custom programmed FPGA and 5 CPLD programmable chip sets to separate the different circuits for avoid any interference in the data process in parallel mode. The R28 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. All digital process mode settings are accessible by buttons on the front. The analog output stage is superb and has a tremendous effect on any DAC’s sound quality. After the D/A conversion by the R2R D/A modules the analog signal is run by fully discrete matched-transistor output stages. These high speed special ACSS output stages are zero-feedback and a current driven design as opposed to the voltage design of most other DAC’s. They are Special because almost all other designs need to convert the signal multiple times from and to current or voltage, resulting in less detail and a less defined sound stage. The Output stage in the R28 has 4 pairs of 15W transistors to offer tremendous output capability. This Diamond Differential design avoids switch distortion. It works in full Class A mode but doesn’t draw large idle current. This balanced drive design lowers noise and distortion and improves the sound stage presentation and transparency.

Audio-Gd R2R R-1 Ladder DAC. This is the 2021 model. Fabulous sounding DAC! I am the second owner. No issues with it. I enjoyed this thoroughly but am upgrading my system. Comes only with power cable. Previous owner purchased direct from Underwood HiFi. Message with questions. Best review Ive seen was from below:https://headphone.guru/audio-gd-r2r-1-fpga-pcm-dsd-dac-done-right/ For additional information and any owners manual/details:http://www.audio-gd.com/R2R/R121/R121EN.htm

Audio-Gd R2R R-1 Ladder DAC. This is the 2021 model. Fabulous sounding DAC! I am the second owner. No issues with it. I enjoyed this thoroughly but am upgrading my system. Comes only with power cable. Previous owner purchased direct from Underwood HiFi. Message with questions. Best review Ive seen was from below:https://headphone.guru/audio-gd-r2r-1-fpga-pcm-dsd-dac-done-right/ For additional information and any owners manual/details:http://www.audio-gd.com/R2R/R121/R121EN.htm

Audio-Gd R2R R-1 Ladder DAC. This is the 2021 model. Fabulous sounding DAC! I am the second owner. No issues with it. I enjoyed this thoroughly but am upgrading my system. Comes only with power cable. Previous owner purchased direct from Underwood HiFi. Message with questions. Best review Ive seen was from below:https://headphone.guru/audio-gd-r2r-1-fpga-pcm-dsd-dac-done-right/ For additional information and any owners manual/details:http://www.audio-gd.com/R2R/R121/R121EN.htm

2018 edition. Real ladder DAC with NOS functionality. In nice shape, but the screws in the top panel show some signs of wear from the first time I rearranged the jumper configuration. Comes double boxed with all accessories. Original product page (http://audio-gd.com/R2R/R2R1/R2R1EN_Use.htm)

AUDIO-GD R2R 11Used state - works perfectly Included: AUDIO-GD R2R 11Power cableUSB cable