The job of updating the Acrosound 20 monoblock amplifier became much easier once I saw a PCB for sale on Ebay. It's a modern iteration of the same circuit, but with all new resistors, capacitors, and tube sockets. Replacement was an easy job and with all the leads soldered into position, the amplifier fired right up on the first try. Now that's always good news.
Some new power supply capacitors are still needed, but I'll wait until I have another matching amplifier before I make that move.
Listening in mono through a fairly efficient test speaker, it's a pretty good sound amplifier. The Acro has some of that general "Class A" sonic footprint - an ease and naturalness to the music that makes tubes worthwhile. It does run quite hot, and appears to be exceeding the maximum plate dissipation of the 6BQ5/EL84, but hey, this is a cheap little tube, so no worries there. Buy 'em cheap and burn 'em up!
