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previous: George Frichter I'm a newbie when it comes to looki... -- 4/14/2000 6:30 PM

Re: mid-70's Pro Reverb cap question

4/14/2000 7:33 PM
Jim S.	Re: mid-70's Pro Reverb cap question The dark blue caps (poylester film and foil) and the orange disk-shaped caps (ceramic) don't usually go bad with age and won't need to be replaced (although they can be upgraded to better performing types giving rather subtle changes to the tone - but this is completely optional). The white plastic cylinders with blue lettering are electrolytics and they all should be replaced. Don't forget to change the larger ones in the bias power supply. Also, if you turn the chassis over and remove the "doghouse" cover that sits behind the preamp tubes, you'll find five large electrolytic caps that should be changed if they're original. These are the main power supply filter caps. If they have brown cardboard covering (rather than plastic), then they are indeed original. While you're doing the cap replacements, you might want to also convert the circuit to blackface specs for an improvement in tone and dynamic response. There is info elsewhere on how to do this and it's not a lot of work.

4/14/2000 7:33 PM

Jim S.

Re: mid-70's Pro Reverb cap question

The dark blue caps (poylester film and foil) and the orange disk-shaped caps (ceramic) don't usually go bad with age and won't need to be replaced (although they can be upgraded to better performing types giving rather subtle changes to the tone - but this is completely optional).

The white plastic cylinders with blue lettering are electrolytics and they all should be replaced. Don't forget to change the larger ones in the bias power supply. Also, if you turn the chassis over and remove the "doghouse" cover that sits behind the preamp tubes, you'll find five large electrolytic caps that should be changed if they're original. These are the main power supply filter caps. If they have brown cardboard covering (rather than plastic), then they are indeed original.

While you're doing the cap replacements, you might want to also convert the circuit to blackface specs for an improvement in tone and dynamic response. There is info elsewhere on how to do this and it's not a lot of work.

Replies:

Gustav If you have a cap tester that can c... -- 4/14/2000 9:12 PM
George Frichter Thanks very much for the advice Jim... -- 4/18/2000 8:24 PM