89' Peavey Triumph 120 Combo Volume drop out while playing

[Joeyblitz]

So ,I had recently bought this Amp about 2 months ago for $200 from CL ,and I was so happy to have a Tube amp again after having sold my Marshalls ,and 3 kids later ,finally trying to get my head back together! It worked perfectly for 2 months ,then all the sudden , I noticed when I turned it on ,and hit the standby switch off ,it would only be on about 1 /10th normal power ,then while playing a few minutes ,would get way louder ,like full power ,then drop out again after a minute or 2 . I have no technical skills at amp repair,but I love this amp ,and cannot afford some fancy Boutique amp ,and do not want some 5 watt Chinese crap for $400 .Any thoughts on what it might be ,and if it would be worth fixing. The Power tubes are all Fender brand tubes that say made in Russia I think. Thanx.

[M Fowler]

Does this amp have a rectifier tube? Because that's what it sound like failed.

Also, if all your tubes are old the power tubes especially could be bad.

[Joeyblitz]

It does not have a rectifier tube as far as I know . it has 4 6L6's in the power section and 3 12AX7's ,and 1 12AT7 in the pre-amp section . I am assuming that the Fender power tubes ,are not the stock tubes from 89' .I should be able to afford to replace the tubes ,but I thought that would be to simple for my life.

[M Fowler]

Yeah it would be using solid state rectifier for 4 6L6 power tubes.

Changing out tubes is the first thing we do but it could be screen resistors that burned out too. Lots of things go wrong in these amps.

[NickC]

Triumph 120's have been around a long time. If the electrolytic caps are original, it's time to replace them.

I have one. It's a PITA to work on. Been thinking of using it as a donor amp for something else.

[Joeyblitz]

So I bought a complete set of JJ's (4 6L6GC's) ,(4 12AX-7's) ( 1 12AT-7) ,and installed them ,cleaned the pots ,and anything else ,I could ,and the amp just basically usually fires up at about 1/10th normal power ,then if I play for like 5 -10 minutes ,it will jump to full power.Sometimes it stays at full power for a while ,but most times only for about 1-2 minutes. Then it goes back to sounding like a 1-2 watt amp.

[Randy Magee]

Sounds kind of like a bad connection in the filament circuit to one or more of the tubes... if you dropped that much money on a set of tubes, I'd take it to someone who could check it for you...

[Joeyblitz]

Yes, I live in Palm Beach ,Florida,there is a Mom & Pop store called "The Amp Shop" I am bringing it there on Tues. It sucks ,to have probs that are beyond my reach. So ,as of now ,I have $200 invested in the Amp,then another $120 on the tube set. Now ,I'm sure it will be at least $100-$200 repair. I-Yi-Yi .......................................... I should have just got a New amp. It is just so hard ,having 3 kids ,if I ever do find a nickle ,it ends up going to them most times.Life is expensive.Again ,thank you for the input!

[Reeltarded]

You have too many kids! Pick one!

[cbass]

Its ben a while since I've been in one of these but I belive they have the tube sockets mounted to the pcb.Thats where I would start looking for bad joint.

[cbass]

It shouldn't take $200 to repair it.unless it needs a new PT or something highly unlikely though

[ampdoc1]

I'll bet it's way easier than folks here suggested. Saw a lot of this in my years as an amp tech. Try spraying some contact cleaner into the loop jacks, then run a 1/4 plug in and out a few times on both. I keep a .22 caliber cleaning brush to burnish i/4" jacks.

a'doc

[Super_Reverb]

I'll bet it's way easier than folks here suggested. Saw a lot of this in my years as an amp tech. Try spraying some contact cleaner into the loop jacks, then run a 1/4 plug in and out a few times on both. I keep a .22 caliber cleaning brush to burnish i/4" jacks.

a'doc

I like the .22 cal brush to keep jacks clean (I assume no Hoppe's #9?)

My son's Marshall SS amp had the same issue. I found that a light whack on the top of cabinet near the effects loop "healed" it. Then I ran a patch cord from effects in to out and that fixed it. In my case, it's the contact on the jack disconnect that's dirty or it's a cheap contact.


rob

[Cliff Schecht]

My bands bass player has an old Crate 120W Blue Voodoo that he is using temporarily for bass duties while I finish his bass amp. The amp used to change channels just from the vibrations of his bass cab. The fix I came up with consisted of a shorted 1/4" plug seated firmly in the channel switching jack. Hasn't caused us any problems since then.

[Joeyblitz]

I had somehow lost the link to this page and just found it now,after all this time. I am super happy to report that after 3 visits(and almost as many weeks in there) to the Amp shop in WPB,Florida, the amp was fixed. It was a bad tube socket for 1 of the 4-12AX-7's (I had mistakenly reported that the amp only had 3,but I was incorrect) .Also ,the tech custom made me tube holder clips to keep them from vibrating out of the sockets! Amazing.This amp is very sweet! What a little beast .Absolutely made for a gigging musician,and a little to powerful for practicing!Incredible tube warmth,and crisp punchy rock sounds.Using the ultra channel,with no effects,with my Jackson DK2M w/Seymour Duncan JB/Jazz Pups ,classic rock sound.However,the EQ,has very little effect on the 2 crunch channels,so it is dark and muddy.Using clean channel,with Boss ME-33, I can get some great sounds.It is a very dated processor,but it is better than nothing! Thanx to all who commented.