Recapping Gibson G-10 questions

[MickeyB]

This is a 1971 transistor style amp with a cap/can in it that reads 500 mfd 3 times. 4 wires coming out of it. The schematic shows it as 2000 mfd. Is 2000uf correct? For cost purposes, can I run 2 1000uf in paralel? What is an acceptable tolerance? 20%?

[Enzo]

1500, 2000, doesn't much matter. Gibson is notorious for changing amps through the production life. SOme changes are minor, like subbing 1500 and 2000uf caps back and forth. Others are major in that the innards of an amp can become a complete other model.

In the old days, the tolerance on can filter caps was -20/+80% Yes, that is not a typo.

it is just a filter cap, the tolerance is not critical at all.

Can you post your schematic? The schematics I have don't agree with your description - typical for Gibson.

[MickeyB]

Hope you can read it. My scanner is not the greatest and the schem/parts list is faded from being inside the back panel for 3 decades.

[Enzo]

I can read it. Looks like most circuits to me. 2200uf would be more likely to find that 2000 in this day and age of common part values, but it still is not all that critical, and yes you can parallel two caps to make one larger equivalent

[MickeyB]

Ok, replaced all the lytic caps. Everything sounds good except when I turn up the treble past 2 it gets a fuzzy distortion and hum. 2 or below its clean and quiet. Any ideas?

[Toddy]

Mickey,
I am also working on a 1972 Gibson G-10 right now. I also change two electrolytics (C7, C13) because they were shot. I was hoping that when I turned the amp back on it would sound better. Nope! The amp still sounds like someone stuffed a pillow into the speaker. The bass pot is not working either.

I came to the conclusion that these amps just do not, and cannot sound good due to the mismatching of the parts according to the schematic and parts list. None of the transistors even match what the schematic says and some of the resistor and caps values are totally different. Without doing a total rebuild, from scratch to accurately match each individual part...I am just going to work on something else!! Oh and yes, everything in the amp is original except for the two caps that I changed!! And, you can't even give these amps away. Last I saw one sold for less that $50 on that eAuction site.

As they say in Monty Python's Holy Grail..."Run away!!" But if you are going to continue to work on your's let me know how it turns out.
Toddy