just listen

My brother dropped this 36+-year-old british hi-fi amp in for service because it was mainly outputting hum. I changed the capacitors in the power supply and power amplifier to get it back up and running, and checked to see if the factory spec was a marketing department fabrication.

Props to Jim Lesurf for providing lots of useful information about these amps: http://www.audiomisc.co.uk/Armstrong/armstrong.html

If you like occasional audio equipment and / or electronics videos please subscribe!

Edit: list of the part numbers I used for replacements:

Reservoir cap (486?)
was 7500uF 90V (schematic says 3300uF?!)
now 8200uF 100V

DC blocking caps (481, one per channel)
was 4000uF
now 4700uF 100V

On the A17 amplifier board (all in pairs, one per channel):

479
was 50uF
now 47uF 63V
Farnell 1165612

478
was 100uF
now 100uF 63V
Farnell 1165613

473
was 10uF
now 10uF 100V
Farnell 2342136

474
was 200uF
now 220uF 100V
Farnell 1165480

472
was 47uF
now 47uF 100V
Farnell 1165565

Armstrong Family Counseling is an established counseling agency with mental health experts who provide unique insights for each client we serve. We understand that every client and every situation is different. Whether you’re looking for a counsel...