Up for a challenge, have a look at my post.

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Mark
Posts: 3271
Joined: Sat Jan 15, 2005 8:10 am
Location: Sydney Australia

Up for a challenge, have a look at my post.

Post by Mark »

I’m having issues with a stubborn AC-30/6 non top boost amp. The main faults are fixed, but channel bleed through is occurring. I have tried resoldering and cleaning earths to no avail,

If you have time have a look and let me know what you think?

Thanks for your time.

https://tubeamparchive.com/viewtopic.php?f=10&t=33748
Yours Sincerely

Mark Abbott
Stevem
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Joined: Fri Jan 24, 2014 3:01 pm
Location: 1/3rd the way out one of the arms of the Milkyway.

Re: Up for a challenge, have a look at my post.

Post by Stevem »

Channel bleed thru issues to me would come from channel mixer resistors that have gone too low in value, or maybe even new bad filter caps that are not isolating power supply nodes, but most times such comes along with motor boating issues.

I have not gone thru any of your previous reference post on this issue, but if it's a board type amp then that could be bad and would be a source for bleed thru.
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Mark
Posts: 3271
Joined: Sat Jan 15, 2005 8:10 am
Location: Sydney Australia

Re: Up for a challenge, have a look at my post.

Post by Mark »

Steve M thanks for your reply. It is quite a read at three pages long.

I have substituted a 16uF cap in place of the 8uF. The 8uF was totally out of the circuit. I put a 2.2uF MKT cap across the 22uF electo (new cap) which is the cathode bypass cap in the brilliant and normal channel, which made no difference. Ironically, if I remove the plate and cathode connections of the normal channel the issue disappears (as you’d expect with reference to the normal channel bleeding into the brilliant channel.)
Yours Sincerely

Mark Abbott
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