Audio-GD

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We are glad to be selling select products from Audio GD. Audio GD is a 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.

NFB-1 Amp
Balanced preamplifier with 8wpc balanced headphone amp

$799.00 delivered
Save $100.00 if bought with an LSA headphone or an LSA Warp One power amplifier
 


 
The NFB-1 Amp is a fully balanced preamplifier with 8 watts per channel balanced headphone amp. All power supplies are run in pure Class A and the headphone amp is all discrete. Parts are all high quality including OCC wiring. It uses a four-channel 100 step digitally controlled relay-based volume control to guarantee exact channel balance for superb imaging. The NFB-1 has a pair single-ended class A FET buffers in the input stage. All the RCA input signals go through these FET buffers. The guarantees the output impedance is very low even if the source has a high output impedance. The FET buffers work in pure class A with very short signal paths. The NFB-1 design has no compromises. It uses a full aluminium chassis, the transformer is shielded from the analog amps and there are two shielded boards to insulate the transformer and the power supplies.  Parts used are all high quality including DALE resistors, WIMA caps and custom made NOVER caps from England. The NFB-1 is a superb preamp and headphone amp at anywhere under $1500.00. We think a steal at only $799.00.

The full balanced design based on Master 9
Class A Power Supplies built in
Discrete Headphone amplifier / Preamplifier
Super accurate Volume Control
8000mW at 40 ohm output for the headphone amp
OCC wire and hi-end parts used throughout

 
"all the usual superlatives goes with this pre-amp, smooth, detailed, transparent, firm bass, etc. Compared to my transformer coupled tube pre-amp it's only a fraction behind in overall soundstage and holographic presentation."
 
 


Specs
S/N Ratio:     >125DB (Volume minimum)
THD:            <0.002 %
Gain :           +16DB
Headphone amp Output Power:  9900MW / 25 ohm    8000MW /  40 ohm   3500MW  /  100 ohm  1200MW / 300 ohm   600MW  /  600 ohm
Preamp Output Level (Max) 10V @ RCA   20V @XLR    2.4MA @ ACSS
Input impedance:  
47K ohm @ RCA   94K ohm @ XLR   <10 ohm @ ACSS
Frequency Bandwidth  (XLR input):  20Hz - 20KHz ( +/- 0DB )   1Hz - 220K (+0DB, -3DB)
Channel Crosstalk: 
> 120DB
Interchannel balance: < 0.05DB
Dimensions  9.4" W x 14.2" D x 3.15 H
 


 
R2R-1 FPGA PCM/DSD DAC
$1,199.00 delivered

The R1 is an R2R full discrete DAC that uses 8 groups fully discrete R-2R DA modules to combine into a real balanced push/pull decoder. it also uses 4 group fully discrete real balanced DSD native decoders. It uses a fully discrete real balanced current transmition design. Jitter is kept ultra low by using dual ultra high frequency 90/98 MHz Accusilicon 318B femtosecond clocks to a provide synchronous clock for the whole unit without using a PLL up-frequency. The R1 works up to 32bit/384K with DSD512 asynchronous USB transfer thru the Amanero 384 FPGA synchronous clock. The entire whole digital circuit is built with single FPGA and 5 CPLD programmable chipsets to separate the different configured circuits to avoid interrupting the data stream process in parallel mode. The unit supports firmware updates future sound quality updates and all digital process mode settings are accessible by buttons on the front. In an R2R ladder DAC the unit switches resistors in parallel mode. An ultra-fast FPGA controls and corrects the R2R ladder. This parallel design mode controls every bit respectively and therefore achieves unprecedented performance. In parallel mode only 1 clock cycle is needed to output all the data so sonics are improved and the output is more analog like. After the D/A conversion by the R2R D/A modules the analog signal is transported by fully discrete matched-transistor output stages. The R1 DAC uses high quality low noise, low flux leakage, R-cores transformers to supply all digital parts and the left and right analog boards. There are in total 13 ultra-high speed and ultra-low noise power supplies built in and double stage PSU technologies are used to remove power supply voltage fluctuations.

Compare this DAC to anything we have heard under $2000.00-$2500.00.
 


R28 (2021 version) Balanced preamp with resistor ladder DAC & 9.5wpc headphone amp
$1499.00

 

The R28 is a fully 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 from the competition.

The R28 features 8 fully discrete R-2R 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 chipsets to separate the different circuits for avoid any interferance 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.
Our price includes the upgraded metal remote control.

 
Inside shot-built like a tank
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 soundstage.
          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 soundstage presentation and transparency.


 
Rear shot showing 6 inputs and 3 sets of ouitputs


Master 10 integrated amplifier
250 watts per channel / 500 watts at 4 ohms / 1000 watts @ 2 ohms

$2999.00

 

The Master 10 is a fully balanced 250 watt per channel remote controlled integrated amp. It is a monster weighing in at 75 pounds and putting out 1000 watts per channel into 2 ohms. It features 2 serts 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 improveed 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 competiton 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 PSU’s power the 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
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