• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Don't you just hate it when

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Hi Gene,
Those polystyrene caps do not like heat. Other than that I've had no trouble with them. I normally use polycarbonate in tube circuits though.

Where ever did you get those ps caps anyway Gene? I am looking for a source on those. The highest I can find from a renewable source is 50V.

Poobah,
Really good troubleshooting sir! Way to go!

-Chris
 
tubelab.com said:
Silver Mica caps were originally used in transmitter circuits where they passed large RF currents. They were excellent for that service. They should be sleeping in a guitar amp. I think you just got one that had a flaw in the mica before it was silverized. The others should be OK.


Your most likely correct.
I did contact Dave at Justradios about those particular Silver Mica caps, He pointed out they do carry 1000V for just a few cents more. Thinking back here now that I have relaxed, The last 4 amps all had that 500V Mica part and none have failed after hundreds of hours. Leave it to me to find the odd one of the bunch.
Wish that happened when I bought a lottery ticket. I would fly all you guys out for a huge audio bash!:cheers:

I buy about 98% of my caps from Justradios, Dave has amazing customer support and satisfaction, And best of all, his pricing is quantity based. I could almost set my watch with his shipping consistency.


So, now for the acid test, I sent the unit back to my brothers. He is better equipped for extended high level volumes.(Padded Cell)
A few days of hammering the thing in his studio, and rehearsal on Saturday.
Monday I hope to sneak over and record a few demo clips. My Recording PC is currently down with a bad drive so I need to spend some time reloading if New Egg ships out on time.

Trout
 
Well Guys, The amp has 2+ hours on it now and It is doing great!

Once again, Thanks to everyone That provided input on the diagnosis. Hopefully we can beat the "bathtub curve" on this one.
Its undergoing the real acid test as I type, If my brother does not blow it up, Then I know its a winner!

<snickering> He called a bit ago worried about blowing his 4X12 Hartke (celestion) speakers instead of the amp. I have no idea on calculating power output, But I am guessing easily well over 35W of clean power.
Trout
 
Trout said:


I buy about 98% of my caps from Justradios, Dave has amazing customer support and satisfaction, And best of all, his pricing is quantity based. I could almost set my watch with his shipping consistency.



I too buy 98% of my caps from Justradios, I would like to take a second to whole-heartedly agree to what you just said, hes a great guy, and his prices truelly cannot be beat
 
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