This one was interesting. Belonging to a smashing gentleman, Chris, it just wasn’t sounding right, plus it also had a bad hum. Although a few components had already been changed (most probably someone looking for this hum problem?), this layout is pretty much how it would have looked originally. Chris asked if I could please leave this fairly untidy layout and not bother tidying it up.
As many-a-time with multiple ground points, it soon became apparent that this was the cause of the said gritty-hum. Here I have lifted the main HT/heaters ground off the power transformer and reconnected it via a cable to other grounds on the amplifier. Hum gone!!
Here the problem is blatantly obvious! A rusty chassis, and this green corroded rivet was being relied upon to carry all the HT and heater grounds from the chassis to the whole of the amp! Not a good thing!
Hard-wired with a piece of solid buss/ground wire here.
A few more duff/tired component changes and she ended-up being “as quiet as a mouse”! Just check-out Chris’ e-mail at the end of the article!
Though I keep saying it…….Job done!
"Hi John,
You've done it again (no surprise). Have just played the Gibson Les Paul Junior amp - absolutely awesome - can't believe the improvement thanks to your superb detective work.
Great to see you again and many thanks for the tea and hospitality - unbeatable service.
Very Best Regards, Chris"