Author Topic: Replacing tubes  (Read 1368 times)

flanagan0718

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Re: Replacing tubes
« Reply #15 on: December 18, 2018, 09:19:09 AM »
So replacing the tubes didn't do the trick. After playing for a solid 15-20 min the amp started to to the exact same thing. Any thoughts? Is it possible that there is a cold solder joint?

WormBoy

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Re: Replacing tubes
« Reply #16 on: December 18, 2018, 01:28:56 PM »
that said, vintage amps rarely had bias adjustment (or even matched tubes) so even if you just end up getting a matched set of tubes you're doing just fine.
Those were different times, when tubes were more consistent (and more tubes were thrown away). You may get lucky though. In general, it won’t blow up, but may not sound its best, which is a pity.

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So replacing the tubes didn't do the trick. After playing for a solid 15-20 min the amp started to to the exact same thing. Any thoughts? Is it possible that there is a cold solder joint?
Take it to a reputable tech and get it sorted out. Tube amps can kill, so I would not mess too much with it unless you know what you’re doing.

PariahBrothermann

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Re: Replacing tubes
« Reply #17 on: December 18, 2018, 02:21:49 PM »
Just a thought... I had this issue with a Laney LC 30 a few years back. Cleaned all valve and jack sockets, especially the effects loop which had been underused, with contact cleaner and it solved the issue. Not sure it will help, but might be worth a pop?
I always take the easy route first if I can.  :D
Good luck!

flanagan0718

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Re: Replacing tubes
« Reply #18 on: December 18, 2018, 03:47:40 PM »
I was emailing with Peavey support and they said the same thing. It may be “connected” Jack. They also said it may be a phase inverter tube 12ax7. I’ll try both of these tonight.


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Bret608

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Re: Replacing tubes
« Reply #19 on: December 18, 2018, 04:02:24 PM »
I was going to mention tube sockets as well. How are those set up on our amp...are the sockets soldered to any kind of daughter board? Sometimes if a solder joint on one of those gets iffy, it will start to get intermittent on you when your amp heats up.

flanagan0718

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Re: Replacing tubes
« Reply #20 on: December 18, 2018, 07:09:05 PM »
I was going to mention tube sockets as well. How are those set up on our amp...are the sockets soldered to any kind of daughter board? Sometimes if a solder joint on one of those gets iffy, it will start to get intermittent on you when your amp heats up.

I’ll take a couple pictures of the amp while I have it apart tonight. I vaguely remember them being soldered to the main PCB.


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Ralfg

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Re: Replacing tubes
« Reply #21 on: December 19, 2018, 12:01:06 AM »
Did you try replacing the phase inverted tube? You mentioned it earlier.
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flanagan0718

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Re: Replacing tubes
« Reply #22 on: December 19, 2018, 08:57:34 AM »
Got it going!!! Here is what I did.

-Cleaned all of the input and output jacks with some Acetone on a Q tip then sprayed compressed air to dry faster.

-Replaced phase inverter tube. I actually had a new 12ax7 hanging around.

-Reflowed solder on the power amp tubes and phase inverter tubes.

Side note I got a “new” set of power tubes from a local guitar shop. He said he had the for 15-20 years or so. He wasn’t sure if they were matched or not but they look vintage and sound good in my amp. There is no brand on them, all they say is 6L6GC and that worked for me. Plus he sold them to me for $10 for the pair. That was nice too! Anyway here are a couple pictures.








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Aentons

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Re: Replacing tubes
« Reply #23 on: December 19, 2018, 09:40:43 AM »
The internet says those tubes are made by Shuguang Electron Group Corp.Ltd.

PariahBrothermann

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Re: Replacing tubes
« Reply #24 on: December 19, 2018, 09:41:25 AM »
Glad you got it working! Nice one.

flanagan0718

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Re: Replacing tubes
« Reply #25 on: December 19, 2018, 09:42:41 AM »
The internet says those tubes are made by Shuguang Electron Group Corp.Ltd.

Cool thanks. I may order a new set of JJs and A / B them.


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Bret608

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Re: Replacing tubes
« Reply #26 on: December 19, 2018, 01:39:18 PM »
Cool! Could have been the phase inverter for sure, but I bet reflowing the joints on those sockets made the biggest impact.

It does feel good to be able to maintain your own gear, doesn't it?