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Pure Class A headphone amp & preamp
Apply ACSS technology, Fully Non-Negative Feedback design
Fully Discrete Transistors Design

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Price: USD3XX  (Exclude shipping cost)
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Summarize Use Manual Specs Shipping Cost

         Class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
         Non- feedback ACSS and output stage designs
         2500mW at 25 ohm Pure Class A ,drives most headphones working in pure class A
         ALPS-27 hifi grade volume port
        12DB and 20DB gain can drive the high and low sensitivity headphones
        3 groups input: RCA X2, ACSS X1
        Preamp output : RCA
         Headphone amp output: 6.3MM X1


Frequency Band (20Hz-20KHz, 1Vrms input, 2Vrms output , set to 20DB gain. )

Frequency Band ( 10Hz-100KHz, 1Vrms input, 2Vrms output , set to 20DB gain. )

THD + Noise (1Vrms input, 2Vrms output )

THD ( 1Vrms input, 2Vrms output )



Technology detail

Detail of the Current Conveyor (ACSS) Technology

Impedance matching:
         There are a lot different quality DACs. They had different design and output impedance . To avoid negative effect on sound quality by differences in DAC's output impedance, in the A-2, we have design a pair diamond differential   buffers in the input . All the RCA input signals go through these  buffers, the output impedance become very low, even if the source have high or low output impedance.
         The diamond differential  buffers working in pure class A , and it has a short signal journey. this way we can keep the sound quality without colouration ,(dry and harsh) .


         A-2 has the ACSS design  . It is a pure class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
         They seem complex , but in fact they are the most simple design the world has ever had . The simplest and shortest signal journey brings out the most neutral and least coloured sound.
         The ACSS is a non-feedback technology made with 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 ears. Here it is a conflict of the classic circuits.
          But the ACSS opens a new field, it can offer a least colouration 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 area, all transistors work in pure class A mode.

Strong class A output stages:
          The A-2 have in its design a pare diamond differential output stages.
          The output stages have two pairs of 20W transistors offer 2500MW at 25 ohm Class A ,drive most headphones (work in pure class A ) ,no matter if you have low sensitivity headphones





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