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Hello may be an easy question for someone to answer.
I have a silver face twin reverb because I like clean forever at silly volumes. Bought it second hand never changed or looked at anything in it until now
However when I'm playing with a drummer or even hitting it with a clean boost it starts breaking up and going all distorted, I like fuzz for that and I'm not into the sound
I looked at the valves and it says they're 5881s which are apparently like lower watt or something than the standard ones according to the net. If I bought a new set of the proper power valves would that stop it from breaking up? Would I need to rebias my amp?
It's just weird you know because everyone's always like twin reverb so loud so clean and this ones loud but not so clean...

While I don't have an answer to your question...
What exact model is it and how old are the tubes? Is the reverb cranked on it?
Maybe post some pictures if you can or even record some clips to show exactly what you mean?

It's a silver face reverb export model from the 1970s tubes could be like thirty years old but seem more like so trek reissues I saw a faint 5881 in black on the tube but everything else has rubbed off. There's a bit of breakup with the reverb but that's pk I get that nd I like that. I mean clean with any dirt even a clean boost like it was running into a low wattage amp
It's not an unpleasant breakup it's just a tube amp breakup at a much lower volume sounds more like a Princeton clone that I own than a twin reverb which is supposed to be super clean all the time.
Recordings won't really show the difference cause its only in band volumes that it breaks up and at that point it'd distort out the bad mice I have anyway
I think the main question is whether 5881 tubes are really all that different to 6l6 ones in terms of breakup and worth buying to put in to bring my amp back to proper clean. Do they really cause the amp to break up so much more you know...

Master volume model? Is the master on ten, the channel volume lower? If not, that's how to dial it in for headroom.

Probably time for some new tubes, and yes you need to check the bias. Matched sets of tubes aren't always matched so if you know someone with a tube tester I'd get them to test any new tubes you get too. You can gently tap on the tubes(power, pre, and PI) and if you can hear the tapping through the amp, it means they are microphonic and likely contributing to your distortion as they will make noise when they are vibrated by the amp, especially at higher volumes. 5881 are lower wattage tubes and will break up before 6L6GC tubes, so for more clean headroom 6L6GC would be the better tube. As always with any amp of that age, a thorough inspection of the components is highly recommended any time you have any troubles. The more often the amp is played, the more the tubes will need to be changed. If it sits in the corner most of the time, then 30 years is a good life span for a tube, but if it's getting played every day, about a year or so is the average life span, give or take.

Yeah, I would replace all the tubes and get it biased and then go from there.
Keep a couple things in mind:
-break up can also come from the speakers
-even a clean fender will breakup when you hit it with something else, even "clean" boost, especially if you're playing loud. I don't know that any tube amp has infinite headroom, or any amp for that matter.

Something else to try:
If you want a clean boost, maybe just set up an A/B switch and use both channels, each at a different volume. I've thought about doing this with my Twin, but haven't really had a use for it yet.

Yea, when in doubt, switch to the right tubes.

The Twin should be loud enough to make you hurt before it goes to breakup, especially on a SF model.

What you're describing sounds like power tube-esque distortion, but it might be preamp tubes as well or something up with the amp.

If it's never been serviced, probably a good time to consider it, it's a 40 year old electronic device operating long past its expected service life.

Tech can rebias/put in whatever tubes you want at the same time as well as advise if there's anything wrong. It's not like you'll be doing this yearly.

Because of the age, I would definitely take the amp in for a checkup, have it rebiased and retubed. It will be glorious.

excane wrote:Because of the age, I would definitely take the amp in for a checkup, have it rebiased and retubed. It will be glorious.

Maybe recapped as well?

Yes, good call on the caps. I believe the Spragues are probably the best for the SF.

I think all my amps probably could stand to be recapped, I just never get around to it.

excane wrote:Yes, good call on the caps. I believe the Spragues are probably the best for the SF.

pop some caps in dat a$$