Tiny through hole capacitors.

Have a amp I'm repairing making all kinds of crazy noises. It has very loud buzzing. Probably more then a bad filter cap and more like a bad amp chip. I'm going to change it. In the mean time I could not find any electrolytic filter caps in the 20 to 50MFD range but the ones I do find seem OK on the ESR meter. However, I'm not sure I trust the ESR meter as a definitive test on smaller sized caps.

Also there are many tiny through hole caps I can't even read the numbers on.

Example: http://kemet.mediaroom.com/2014-10-07-KEMET-Introduces-New-Through-Hole-Ceramic-Capacitors-for-High-Temperature-and-Automotive-Applications-up-to-150-Degrees-Celsius

Can anyone tell me if these have a tenancy to be good or go bad. Also could the AC filter caps be this size?

Thank You

Ceramic capacitors rarely go bad. Filter capacitors in regular old "analog" power supplies are usually 1000uF or more.

Is this a modern solid state amp or a tube amp? If it's a modern amp with a regulated power supply, the regulator circuit may have failed. (The regulator also acts as a filter.)

It could also be a broken ground connection. With a broken/open ground on the input, the buzz will be worse with an input-cable plugged-in.

caps in the 20 to 50MFD range

you don't mean Megafarads.

What do you mean? mF or uF?

farad, symbol F (not FD) mega, symbol M, 10^6 milli, symbol m, 10^-3 micro, symbol u (more properly greek letter mu), 10^-6

Case always matters for units and prefix symbols.

It is just mF like usual. It's got a few small transistors and op amps then a "Pentawatt" chip for the final stage. It's only a 50 watt Guitar amp made by Crate. Seems fairly old.

Coincidentally, I found a ground pin on the input jack which I believe was floating and the actual jack was loose and corroded and I doubt it made a good connection if at all. Really did not find and bad filter caps or transistors. 1 Transistor seems a bit away from the other 3 so I think I will change that and the op amps are cheap so I may change them just because I'm already paying the shipping.