Sunday, March 31, 2019

Burning Amp 1

To get warm and comfortable on long winter evenings, in the end of 2010 I built myself a Burning Amplifier 1. With its 300W quiescent dissipation and ineffable ((c) Nelson Pass) sound, it is a nice winter time companion.

The enclosure, heatsinks and fans, power supply and speaker protection were salvaged from  my previous (not documented and hence not posted) attempt to build a Krell KSA-50 clone. The Krell clone worked but sounded strange, and I did not have the skills at the time to make it right.

I used four heatsinks, each holding two IRF250 MOSFETs in TO-3 packages and a PCB. Each pair of heatsinks is cooled by a quiet 140mm fan. Power supply uses a 400W toroidal transformer and 2x40,000 uF per channel; it is a dual mono configuration. The amplifier is housed in a 5U 400mm deep enclosure from modushop. Their "pierced" (perforated) base plate was very handy to keep all the parts together without sacrificing the looks. Total weight is about 50 pounds.

The knob on the front panel was designed as volume control, but it looked ugly, so I later remove it and replaced with a ON/OFF button.