I am based in the UK and have a Triumph 120. I recently revalved the amp with nice valves... front end Groove Tubes 12ax7m.... back end Harma 6L6. The bottom end has dropped out after 4 weeks . I heard that this amp is notorious for this. Any ideas?
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Re: Peavey Triumph 120
Here is a good place to start. Check the tubes for you... supposing here that he does have a tube checker ... I mean I have... :). A FixYa rating will help me build my profile in here. If you want to talk in more depth about the problem, rate me FixYa and I am yours.
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If you've never replaced a tweeter diaphragm, then maybe you should seek out someone local who has. These guys are a bit fragile and misalignment can turn it into garbage. On the other side of this discussion...overpowering speakers blows tweeters 1st because their voice coil windings are so small, and are more easily damaged. Re-examine your PA setup and adjustments or you'll find yourself back on the phone ordering more diaphragms.
I believe there's a fuse on the main board inside that supplies the heater voltage.
The heaters are what cause the tubes to glow.
If you try going inside yourself BEWARE of high-voltage-human-killing potentials inside
This could be anything. You could try swapping the preamp tubes. If it were a power amp tube problem, it is likely the mains fuse would have blown, Since the pilot lamp is still on, we will assume that the problem is at the preamp level. This absence of signal can be caused by a dead tube, or more complexly, by a faulty resistor or capacitor in the signal path. If you can't resolve the problem by swapping preamp tubes with a known good one, you should take the amp to a tech experienced in servicing tube guitar amps. Any good tech should be able to sort this out within an hour of labor time. I doubt it will require any expensive parts. It may even be as simple as a loose/bad connection, either from manufacturing, or from normal use. Pro tube amps are subjected to levels of heat, vibration and electrical stresses that consumer electronic gear never sees.
Switch your amp on and leave it in the stand-by mode, you see tubes glowing.
Than you can pull another tube (same type) out of the amplifier and put it in those sockets. If they are also not glowing, there must be a wiring problem.
It very strange that there are two tubes not glowing.
Give it a try, you can do it yourself.
If you switch on the amplifier, do you hear nothing at all?
Or do you hear low level noise or hum out of the speaker? Don't know if you're technician.
If the tubes are glowing, you can measure the high voltage.
Check also fuse 3 and 4, thats the neg. voltage -27V and -14V.
I'm not sure what "PT" is , but the heater voltage is separate from the other voltages required for this unit to function properly. Please note that with tube systems, there are voltages in the 300-400V range that can cause injury. If you do not have experience with tube based electronics, I would suggest that you bring this to a service center for repair.
Please update this with what you mean by "PT" and we'll continue from there.
I have a classic 50/50 as well and re-tubed it with JJ el84s, vintage teslas and mullard 12at7s. As long as you replaced it with EL84s, I can't imagine that the output would be increased enough to damage the OT. When I got my 6505 Combo, one of the 6L6s was bad, and it kept blowing fuses and howling like a banshee. I would think that an OT problem would result in a significant loss of output...or none at all. I've gotten DOA tubes from a few places. I would suggest swapping each tube out 1 by 1, until you find it...if that is indeed the problem...before you pay the cash to have it worked on.