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Post by ksquared on Jun 18, 2018 8:00:54 GMT -7
Hi all. Seeking a little troubleshooting help. I have a nearly brand new Z-Lux. I'm hearing a noise that sounds like "frying" or "sizzling" while a note is sounding. It is quiet when not playing, not a hum issue. You hear the notes when playing (and they sound good) but with a frying in the background. Sometimes notes will cut out briefly; not completely, but a big volume drop. The amp settings don't affect it at all. Then, it seems to be going away after maybe ten or fifteen minutes or so after powering on.
Is it as simple as that I'm not letting the amp warm up enough? I will power up, plug in and tune up, wait maybe a minute, then flip the standby switch. That routine always works with my Maz. Does the Z-Lux just need a few minutes longer? Assuming it is a warmup issue, is it normal to take more than a couple minutes?
This likely doesn't matter, but FWIW while the amp is brand new to me, it was at the dealer for a while. I know this as it came with the footswitch without the variable boost.
Anyone have any thoughts? I just want to rule out as much as possible before reaching out to customer service. (I'm pretty sure it isn't a big issue as the amp otherwise is fantastic.) Thanks.
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Post by KeithA on Jun 18, 2018 8:03:34 GMT -7
'Frying pan' noise has always been a preamp (12ax7) for me. If you have a spare simply pull & replace eack preamp tube (one at a time) to see if a single one is the culprit).
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Post by Jaguarguy (Mike) on Jun 18, 2018 8:06:41 GMT -7
I agree with Keith - swap out one at a time until you find the bad one.
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Post by daddyelmis (Greg) on Jun 18, 2018 8:34:17 GMT -7
If you’re running guitar straight to amp then maybe preamp tune. If you’re using any pedals, check the connections. Also, as is always said (and particularly with an amp that may have been sitting in a dealer for a while) spray some DeOxit on all the connectors and work a plug in and out a bit. Getting oxidation or other gunk can cause that staticy frying pan sound.
Check Docs AMA on annual amp maintenance and go through that process - simple, easy, and gets all the easy stuff out of the equation.
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Post by Chilly Gibbons (Todd T.) on Jun 18, 2018 10:56:53 GMT -7
Most likely a tube issue. One easy thing to try is to make sure all of the tubes are seated correctly. Take each tube and rock it in a circular motion in their sockets, sort of like you were going to pull them out but after a few cycles, push them in all the way.
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Post by ksquared on Jun 18, 2018 11:50:24 GMT -7
Most likely a tube issue. One easy thing to try is to make sure all of the tubes are seated correctly. Take each tube and rock it in a circular motion in their sockets, sort of like you were going to pull them out but after a few cycles, push them in all the way. That will be my first step, for sure, and it may make sense as the amp was recently shipped and I suppose things could have loosened. Then deoxit (gotta go buy some). If not fixed, then I'll try a spare 12ax7 in the pre-amp positions. I'll report back with results. Thanks all!
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Post by ksquared on Jun 19, 2018 7:31:12 GMT -7
Quick update: I re-seated all the tubes, then plugged in and waited about 2 minutes to flip the standby switch. I still heard a bit of the frying sound, but it had lessened quite a bit, and it dissipated much faster (only a few more minutes). I will repeat later, and maybe use deoxit. Hopefully that's all it will need.
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Post by John on Jun 19, 2018 12:16:10 GMT -7
I'd still start tube swapping to see if you can find a bad tube. My money is on bad tube vs tube that's not seated correctly. The preamp tubes don't get so hot....that means you can pop them in and out quickly. (I'd still flip the stand by switch each time)
Power tubes can get hot and burn your fingers, so be careful.
If you get the sizzle but no loss of power...I'd start with the preamp tubes. If there's a loss of power, then I'd go after the power tubes.
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Post by Chilly Gibbons (Todd T.) on Jun 19, 2018 12:40:16 GMT -7
Also try tapping lightly on the tubes while the amp on and standby disengaged. You’ll likely be able to hear your culprit.
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Post by ksquared on Jun 25, 2018 16:35:59 GMT -7
OP here, reporting on troubleshooting progress. I believe I had more than one problem. I got some deoxit (actually the CRC brand contact cleaner), and used it everywhere -- input jack, speaker jack, brakelite jack, tube pins. It seemed to work, and certainly made louder pops/crackles on warmup go away. But then, I heard it again -- a darn frying or buzzing behind the note being played. Worse on some notes than others. Next, I set about tapping the output tubes with a pencil, and it seems the second in line (V8) is a rattler. It's not the whole tube rattling in its socket, it's like a buzz inside the tube. Is this my culprit?
I don't have a matched quad of 6v6s handy, but I do have one I can swap from another amp. Is there any harm in testing it in V8? Would that be conclusive?
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Post by purpletele on Jun 25, 2018 19:08:28 GMT -7
There is no harm in trying a random tube.
If it is significantly mismatched then it might make noise but its not going to hurt the transformer.
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Post by meanslide on Jun 27, 2018 14:35:12 GMT -7
I had the same issue and a new set of tubes (minus V3) fixed it for me...
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Post by redzsrock on Nov 25, 2018 14:04:42 GMT -7
Not trying to hijack this thread, but my situation is a similar.
I hear the “sizzling” noise when NO note is sounding.
Should I start by replacing preamp tubes?
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Post by purpletele on Nov 26, 2018 11:42:46 GMT -7
Not trying to hijack this thread, but my situation is a similar. I hear the “sizzling” noise when NO note is sounding. Should I start by replacing preamp tubes? yes indeed! We want to understand the sizzling noise.
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Post by zpilot on Nov 28, 2018 14:02:27 GMT -7
Almost certainly something is microphonic. Most likely a tube.
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