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AUDIO FORUMS >> General Discussion and Support >> Absent of sound
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Message started by fidelity71 on 02/10/18 at 21:41:32

Title: Absent of sound
Post by fidelity71 on 02/10/18 at 21:41:32

Hi all, up until last night I've enjoyed my Zkit84.
the left channel stopped reproducing sound while right channel continued to.
I've tested all resistors they checked fine.
2. checked opt's - ohms from B+ to plate checked fine but sttill may be bad?
My DMM has a cap test, the electrolyctic cap test fine. all others will not read on my DMM.
3. switched output tubes no resilolution to sound
4. I've checked input source plugged into Alt. amp both channels work.
short of replacing all Caps and a potential opt.
Am I missing a test?
I also checked amp while live, with out knowing exactly what and where voltage should be, hard to determin where a fault is. How ever at coupling caps test about 325v or so(both channels)

Thanks to all who respond

Title: Re: Absent of sound
Post by Steve Deckert on 02/10/18 at 23:43:13

Since the amp doesn't have enough power to blow itself up, and you swapped output tubes with no results, it's time to test or replace the input tube, and then if that doesn't do it, look for a shorted input on the channel that has no sound.

Steve

Title: Re: Absent of sound
Post by fidelity71 on 02/11/18 at 13:57:09

Thank you Steve,

quite often the solution to most problems have the simplest answer.
I overlooked the gainstage input tube. Although it glowed normally, clearly it was bad. Following Steves advice It was replaced, along with checking board for possible short. No short was detected.

reconnected amp to speakers and input source, with hand at the ready to switch unit off.

Sound....both channels, crisis averted.

Thank You again Steve for your advise and quick response.
All the best for 2018.

Title: Re: Absent of sound
Post by hdrider on 02/11/18 at 15:33:33

Fidelity71- Glad you are back in the tunes! I have always found that most issues with our Decware gear was pilot error...meaning I miss wired an input on our Rachael after taking it out to clean contacts etc. I always have a spare set of stock tubes (from Decware) that I keep as a base line. Glad you are back in action. Happy listening, Chris.

Title: Re: Absent of sound
Post by dank on 02/11/18 at 16:12:44

What is a Zkit84?

Dan

Title: Re: Absent of sound
Post by hdrider on 02/11/18 at 17:32:26

Dan- One of the kits that Steve still offers, I started with a CS84SE kit way back and still have it. Happy listening, Chris.

Title: Re: Absent of sound
Post by Acetone on 02/12/18 at 17:01:10

Hey 71, I had same thing happen with a 6922 in my superzen. Tried the output tubes, then the rectifier before finding the culprit. I've also had a bad rectifier, and in a another case an input tube, that caused a subtle high frequency signal in one channel.