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EQUIPMENT FORUMS >> SE84UFO >> Scratchy, Static-y noise during warm up
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Message started by jrubins on 06/26/24 at 17:50:37

Title: Scratchy, Static-y noise during warm up
Post by jrubins on 06/26/24 at 17:50:37

Hey Decware crew. I've had my Zen Triode for a bit less than a year, and i absolutely adore this thing! However ... A couple of months back, it developed a scratchy noise after turn on, during the warm up, and only in the right channel. I wouldn't worry too much, but sometimes i hear it during normal operation now. :(
1) How can i best diagnose this problem?
2) If it's something known/obvious, how can i fix it?
3) If the amp needs to be repaired, what are the steps?
short video (little more than a minute) demonstrating the noise during startup here:

youtu.be/RVFM6jn1zNc?si=lhsbvHn8NEyoid9Q

This noise happens with both inputs, same volume regardless of volume pot position. I have swapped speaker connections around and the noise follows the right channel of the amp (doesn't stick to the right speaker).

Title: Re: Scratchy, Static-y noise during warm up
Post by jrubins on 06/26/24 at 17:52:29

apparently, i can't put a link in a post until a post a few more times, so copy/paste into browser will have to suffice :)

Title: Re: Scratchy, Static-y noise during warm up
Post by mrchipster on 06/26/24 at 20:20:57

Hopefully it's something as simple as a tube starting to fail.

If you swap the output tubes does the static follow it?

If you have backups of the tubes, you could try the replacements first and see what happens.

Good luck and I hope it's something simple.

Title: Re: Scratchy, Static-y noise during warm up
Post by CAJames on 06/26/24 at 20:35:07

Quote:

Posted by: mrchipster Posted on: Today at 12:20:57

...If you have backups of the tubes, you could try the replacements first and see what happens.

Agree it sounds like a tube going bad. And if you don't have (at least one) full set up backup tubes you really need it. Cuz you never know when a tube will go bad.

Title: Re: Scratchy, Static-y noise during warm up
Post by jrubins on 06/27/24 at 01:10:56

Tube going bad after less than a year ?!
Is that to be expected?
I’ll swap the output tubes around and see if that changes anything.
Thanks!

Title: Re: Scratchy, Static-y noise during warm up
Post by CAJames on 06/27/24 at 02:28:04

Quote:

Posted by: jrubins Posted on: Today at 17:10:56
Tube going bad after less than a year ?!
Is that to be expected?

It's more about how many hours the amp has been powered on than days on the calendar, but sure, if you listen to the amp a lot a year would be a good run for the power tubes and/or the rectifier. The input tube ought to last a little longer, but the bottom line with tubes is any tube can go bad at any time.

This is why it is important to have spares on hand: if something starts to sound funny, esp. if it is a scratchy, staticy, "frying egg sound" your first thought should be to start swapping tubes, because, at least in my experience, 90+% of the time that is the problem.

Title: Re: Scratchy, Static-y noise during warm up
Post by jrubins on 06/27/24 at 03:05:53

Well damn! :'( :'(
Any recs on replacements , sources ?

Title: Re: Scratchy, Static-y noise during warm up
Post by CAJames on 06/27/24 at 03:30:15

Oh Boy.

There are about a thousand threads on this site about tubes. If you are actually interested in tubes the best thing you can do is just start reading.

The easy recommendation is get replacements from Decware, if you don't want to think about it. The exception might be rectifiers. You are much better off buying so called New Old Stock (NOS) rectifiers from the 40s-70s vs. current production. Here is a thread about buying your first NOS rectifier:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1605822949

It is a couple of years old, but I think the advice still stands.

And here is a recent thread, covering pretty much the same ground as you are asking:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1711643616

So look around and if you have questions don't hesitate to ask.