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Altec can capacitor upgrade?

Hope it helps you out Grey, doing some drawings would have taken less time, and been a lot less wordy. Good luck with your altec's, they are great amps!
 
Updated pics of altec. This one is working with no noise or hum on my small test speaker. Sounds loud and clear. I measured 428V on c11 and 387v on c6b. C6A measures perfect at 250V. ????
 

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Glassweights said:
I would certainly not change the value of the first capacitance after your tube rectifiers by much, since the spec is 40uf for the 5U4G.

That said, you can up it little, some people increase it a lot, but I think that puts your rectifiers at risk of flashover.

The second capacitor is fair game and I increase that one on every one of my amps to 80uf-120uf. For my ears it tightens up the bass a lot. (But so would just putting in new caps!)

The third position I have seen it done both ways and heard arguments that that last cap filters the whole power supply.

On the other hand, as you can see a lot of people like to keep their old hardware stock values, and you can be certain that is a very very safe thing to do most of the time.

The best part is, you have some wonderful pieces and a very nice dilemma. Picking parts is actually 2/3 of the fun for me!

If you post pics as you go we will all enjoy it more than you know.

Dan
Click to expand...

I agree..... 50uf max with a 5ar4/gz34
 
analog addict said:
Nice fire extinguisher....:smoke:
Click to expand...
Yup, no flames....yet:D

I'm wondering what the deal is with the high voltage? it's ~40v too high at c11. It should be ~390v. Has me a little worried. If I lower the voltage here somehow, I would think that the voltage in the first stage would be too low??? The line is at 116v.

I listened to it for about an hour in hi-fi MONO:banana: before i noticed one of the sylvania output tubes was hot. Not red plating, but at a considerably higher temp. I didn't test those tubes, so I guess this is to be expected.

My impressions so far are VERY good. I will wait to comment any further until I have more time with them.
 
Never mind.....the voltage is fine. I was not looking at the revised schematic:stupid: The only point slightly off is pin1 on V2. It's ~20v too low even if C6B is ~35V high. Not enough to worry about. I assume that R12 & R13 are just old and drifting under power.

Even with a matched set of tubes, one tube(different socket) is still burning ~100 deg. hotter. I assume that it's pulling more current than the others. I can't see that tube lasting very long. I will need to go forth with biasing them individually.
 
Finished the second one tonight.:) I have them biased a little cold for now. Thanks for all of the help from everyone.:thmbsp:
 

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