This is the legendary J. Hiraga 8W Class A Amplifier. I tried to build this amplifier as close as possible to the original. The main problem is to find the original transistors - I used GR grade Jfets and ISC 2SB754 and 2SD844 output transistors. Instead of pots I used fixed resistors and dc offset is 5mV for one channel and about 10mV for other.
Amplifier bias is set to 0.7A.

Power supply details :
200VA transformer;
Schottky diodes;
CRC filter (40000uf 0.1R 40000uf per rail)
output: 2x13.6V.
Enclosure from modushop.biz
10R Thermistor is used for soft start.
Switch from Onpow.
Amplifier Damping factor is low - about 10 or so.

I am really excited how this small amplifier sounds, its sounds divine.
Thanks to author of the circuit and the diyaudio community.

Comments

• Sebb
• 23 January 2012 at 03:06PM
• Well done osscar - sure such a build can sound great...
  Could you share schematics of the power supply (transformer voltage, diode rating, wattage of CRC resistance ? About Schottky diodes : really superior to heavy-duty diode bridge ?
  Cheers from Paris -