Audio-gd ::PRECISION-1 Non-Feedback Discrete ACSS Integrated Amp / Headphone Amp 90W X2 (8 Ohms) & 16W X2 (40 Ohms Headphone)
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Precision 1 - Non-Feedback Discrete ACSS Integrated Amp / Headphone Amp#


Precision 1

Precision 1 is designed to enable the whole chassis to work as a heatsink, the chassis is of pure aluminium, having a 3.7KG weight and a very large heat flow area, improving over standard heatsinks (usually products in this size range have less than 1KG of heatsinks), the Precision 1 stays at a safer temperature.

Please note: The Precision 1 is too powerful and it is not for the in-ear headphone.

  • Fully discrete design, Non- feedback ACSS analog amps.
  • The gain stages and pre-driver stages working in class A, built with discrete analog stages without any OPA and coupling caps in the signal channels.
  • The Diamond Cross Non-feedback output stages design can avoid "switch distortion", rivaling class A amps.
  • Full functions (DC offset and overload) MCU protection detect for protecting speakers and the amp.
  • Separate two channel 80 steps digitally controlled relay-based volume control avoids channel imbalance, channel cross and improves sound quality .
  • High / Low volume model, easily handles varied sensitivity headphones and speakers.
  • 4 analog inputs: RCA X3, ACSS X1
  • Applies 8 transistors ( 150W / 15A / pc). Supports 90W X2 (8 Ohms) output or 16W X2 (40 Ohms).
  • The capacitance of the whole machine reaches as high as 45,000 uF, 450W transformers.
  • A total of 2 groups of high-quality class A parallel connection PSU power supplies for the gain stages. To achieve high S/N, the control circuit is powered with separate regulators.
  • Applies all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps.
  • Between the transformers and signal amps resides a thick metal board to avoid disturbance.
  • Remote control

Precision 1
Precision 1
Precision 1

Precision 1 is a discrete design applying the newest ACSS design which can improved the RCA connection to sound as good as the ACSS connection. It seems complex, but in fact they are the most simple design the world has ever had, their a lot components to process the power supply. The Precision 1 power amp only has a single "voltage" gain stage to process signals, but works in ACSS mode so in fact it is a current gain stage instead of voltage gain stage, whereas normal design amps already include two or three voltage gain stages. The simplest and shortest signal journey brings out the most neutral and least colored sound.
Precision 1 applies ultra-low distortion single stage ACSS amplifier and soldered directly on the motherboard. The gain stages and pre-driver stages working on class A.
The diamond cross output stage design can avoid "switch distortion" as good as the class A amp.
The ACSS is a non-feedback technology made with fully discrete amplifiers. Most people know the global feedback design can offer better specs in test measurements, and non-feedback can't do well in test measurements but can offer better sound for the human's ears. Here is a conflict of the classic circuits. But the ACSS opens a new field, it can offer a least coloration sound which is more neutral with very low distortion and high linearity. So it can retain the dynamics, detail and neutral sound but not sound bright or harsh.
All signal gain is in current, achieved by the unique, superb open-loop multiple output current mirror. Incomparably precise and ultra-low distortion in the gain signal is the result. The signal path is balanced throughout and all transistors work in class A mode.
The ACSS parts use 2 groups of high-quality class A parallel connection PSU supply. The class A parallel connection PSU has very high input impedance to avoid pulse from the PSU from affecting the gain stages, and low output impedance with very fast speed and high linear, so it is a very clean power supply.

Full discrete ACSS Non-Feedback amps

Precision 1

THD ( 0DBV , AP SYS-2722)

Precision 1


Massive use of high power parts and robust power supply guarantee vigorous current output that drives most existing loudspeakers. Precision 1 applies two channels of diamond non-feedback output stages composed of 8 pieces transistors ,every transistors have 150W / 15A . The capacitance of the whole machine reaches as high as 45,000uF. The transformers used are 450W.
The Precision 1 have very wide frequency band, excellent phase distortion, boost the amp have excellent detail and dynamic reproduce.

Volume control:#

The volume control is also different from conventional technology. Conventional volume control technology is the volume control implement in the analog amp input stage through a volume pot to reduce the signal. The volume pots quality effect the sound quality direct, the low quality volume pot cause lost the detail and channels imbalance cause the soundstage distortion. Even the high performance volume pot still cause the detail lose. Whatever quality volume pots, must cause the S/N worst.
But in the Precision 1, we applied the I/V conversion volume control, the volume control just a variable passive I/V conversion place at the ACSS amp output, where the output is the current signal, not the voltage signal. The volume control is I/V conversion, and the volume depends on the current (I) conversion to the voltage (V). (Like R-2R D/A chips output passive I/V conversion) It can keep the signal frequency band flat and not lost any detail. It can't degrade on sound quality in every volume level. After the volume.
Mark Levinson also knows that current volume control has great benefits, so in their Top End preamp NO.32 volume control, they use many components to change the signal to current signal (I), then implement the volume control , and then change back to voltage signal (V) again. But Precision 1 is simply a more complete work in terms of the current signal, and technically, it is superior to conventional technology. The less conversion bring much neutral sound.
The volume control quality is very important. It must guarantee the two channels signal control exact to achieve image of the musics playback . In Precision 1, for avoid the channels signal cross, it had applied a four channels digital control relays based volume control, through changing the DALE resistors to control the volume for avoid channels imbalanced and channels cross. Two channel implement low volume control another two channels implement high volume control , so Precision 1 can have very wide volume control performance. While change the volume, the different relays break or close, it may had slightly switch sound on output and disappear while stop change the volume.

Precision 1

Diamond Cross Zero distortion Non- Feedback output stages#

Precision 1

Frequency Band (2.83V ,AP SYS-2722)#

Precision 1

Input: #

Precision 1 three groups RCA single end signal, but also the top grade ACSS current signal. No matter what kind of signal it is input.
Shield and avoid vibration:
Precision 1 uses heavyweight all aluminum alloy chassis to prevent the eddy current of transformers from interfering with the circuit board. The interior is separated into 2 sections with aluminum boards for the best separation off the ACSS parts, the output stages and transformers. The AC power input wire is shielded by a copper channel from back to front.

Precision 1 take care the vibration for the best sound playback. Each channels gain parts under a aluminum heatsink, these aluminum heatsink not only poise the heat between cool and hot amps, our workers care to install all transistors cling the aluminum board for avoid the vibration cause the sounding worst. From our testing, with the aluminum board bring clear detail reproduce and less harsh than take off the aluminum board.