A-2

2500mW Pure Class A Headphone Amp & Preamp
Apply ACSS technology, Fully Non-Negative Feedback design
Fully Discrete Transistors Design
　

Summarize
         Class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
         2 pair accurate matched  20W (in total 80W Pcm) output transistors .
         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
        14DB 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
         Built in two groups sound flavor settings for users tweak the sound match with the system or personal favorite

Fully discrete transistor amps design:
        

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) .
             
Core:
         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

Hi-Fi parts apply:
          Though the A-2's price is low but it apply the high grade parts, include the well know good sound quality ALPS volume port , foot holes transistors ,high performance R core transformer, full aluminum chassis, CMC RCA sockets, there is no compromise on the building quality .