I am all for measuring them first, then deciding what to do. Even if the chance of them still being good and from the 70s is low.LD50 wrote: ↑Thu Dec 26, 2019 6:05 pmThere is an element of truth in the above, although personally, I am against the didactic replacement of working filter capacitors in a fully functioning vintage amp. Having changed the voice of some old amps with a recap (and not always for the better) I will replace when caps are failing (ghosting, ripple hum, physically leaking electrolyte) without hesitation.megalithic wrote:Can't say I'm an expert in electrolytic capacitor brands, but they don't look that new and they should probably be replaced after 25 years.
Someone else may have a better idea, seems like that company is still in business, but I couldn't find that they still make electrolytic caps.
The amp will still work if those caps are faulty, but it won't be as loud and may cause some other components to fail.
In this case if the amp is not as loud and clean as you wish or it has become a little noisy with mains hum coming through then a cap change may help. For this you need x2 100uF 500v radial cans for the mains caps on the chassis,
x2 32uF (or 33uF 500v) axial caps for the screens, x2 16uF 500v axial caps for the preamp. Sometimes 16uF is hard to find so I would go up to 22uF rather down to 15uF.
I think the TAD versions are best.
I checked out one amp from the 90s, it actually has one electrolytic (out of about 7) still working fully.
The rest are mostly functional, but read about half of what they should.