Passdiy Arch Nemesis
SIT Amplifier (Static Induction Transistor)
SIT Amplifier - L'Amp - part 1
SIT Amplifier - L'Amp - Part 2
The Arch Nemesis or the SIT amplifier can be considered the simplest solid state class A amplifier there is. Even the ACA amplifier (Amp Camp) amplifier is not as simple as this. With SIT transistors behaving like a triode, it carries some of the sonic signature tube-o-philes like. For those that prefer triode sound without the tube hassle, SIT amplifier or the Arch Nemesis are good choices to consider.
The use of output transformer in transistor amplifier can actually be traced back to 1980's where Jean Hiraga wrote about having a simple Mosfet amplifier named Nemesis. There are several methods of coupling for such simplistic amplifiers - RC coupled, DC coupled or transformer coupled and we prefer the latter, transformer coupled SIT Amplifier or Arch Nemesis.
- RC coupled - R dissipates a lot of heat, and C needs to be huge and therefore high quality capacitors cannot be used.
- DC coupled - needs bipolar supply and is disastrous if something fails and fries the speakers.
- Transformer coupled - safest, dissipates least heat, but bandwidth limited.
- EI Z11 Level 1, 10W @ 20Hz - U$299/pair
- EI Z11 Level 2, 10W @ 20Hz - U$599/pair
Both are significant upgrade to the RC coupled class A amplifier, be it Arch Nemesis, SIT amplifier, or any class A solid state transistor amplifier that you care to build!
J&K Audio Design