Peavey Amp Tube Problem

Stephen Winters · Post by **Stephen Winters** » 17 Dec 2002 7:52 am

Yesterday I replaced the tubes in my old Peavey Deuce. The old ones are 6L6GC, so I bought a "matched set" of four 6l6GC's. When I plugged them in and powered up, there was a lot of crackling and poping and a loud hum. I was afraid of some tubes blowing, so I powered off. I placed the old tubes back in, and the amp sounded fine.

The matched tubes are numbered nr90, nr115, nr208 and nr344. Do they go in a certain arrangement? I know they were seated good before I powered up.

I am a tube amp novice. Any help would be appreciated. Thanks

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Stephen Winters
Carter Starter
Peavey Deuce

Gino Iorfida · Post by **Gino Iorfida** » 17 Dec 2002 9:03 am

The amp may need a bias adjustment. It sounds like the new tubes were running WAYYYYY hot. Take the amp to a tech to have him put in the new tubes and set the bias.

Ken Fox · Post by **Ken Fox** » 17 Dec 2002 10:06 am

There are a lot of known instant failures with Sovtek 6L6WXT+ tubes. Do not be surprised if you have a bad one right out of the batch! A failure rate of 50% percent is not uncommon with these tubes. There has been a lot of discussion about the quality of these over on the Fender Forum. Might I suggest JKJ/Telsa or NOS tubes? The JJ tubes can hanle high plate voltages (up to 500 WVDC) and have a 30 per tube power rating. The amp does not have a bias adjust pot. It will require a tech to change the bias resistor or add a bias pot for this amp. I would test the tubes on a tube tester right away and especially looks for internal shorts in the tubes. I have had several of these amps in the past. I had a Mace that took out 6 each 6L6GC every 3 to 4 months when I was playing six nights a week in Georgia, back in the late seventies. The problem was that our household voltage was close to 130VAC there, so my tubes were biased too hot! We finally changed the bias and no more problems. When the bias was too hot, the tubes would eventually "red plate". That is thermal runaway and tube plate meltdown! The amp would may a low pulsing sound and promply blow the fuse! The Deuce and Mace were and still are great Peavey tube amps!

Mike Brown · Post by **Mike Brown** » 19 Dec 2002 7:26 am

Sounds like a defective tube to us.