Fender Super Twin #2

[rsm]

Super Twin #2 arrived today. It survived UPS undamaged, unlike Super Twin #1.

Sounds quieter than #1 but I'm getting distortion at low volumes, where #1 is clean at the same settings. It doesn't sound like the distortion from the built-in distortion, it sounds like natural tube distortion...maybe I have a bad tube?

Which tubes are most likely to cause distortion if it's bad?

These have so many tubes in it, I'd rather not swap each one randomly to see if one is bad...where should I start, power tubes, preamp tubes? I do have new tubes in #1, so I can use them to test.

Super Twin #2

 

[JackBootedThug]

Probably v1…..should be clean till damn near max though right? Supertwin? Not sure though. Might ask vonbonfire…he’s the resident twin man….

 

[rsm]

Probably v1…..should be clean till damn near max though right? Supertwin? Not sure though. Might ask vonbonfire…he’s the resident twin man….

Yes, the #1 stays clean almost to max; #2 is distorted at any volume, pre- or master- at any level.

 

[VonBonfire]

Congrats on the amp making it intact. Looks clean. I wanted to joke with you the other day that now you have two amps that need servicing but didn't wanna rain on your parade. The reality is the things are old, most people are too big of wimps to haul them to gigs, so there they sit deteriorating internally in someone's back bedroom.

I'm no expert on Twins and perhaps not in this order here are some things to examine:

Check the speaker connections and the jack on the back. Make sure it looks to be in good shape and the connections are clean both to the speaker and to the jack. I've had original wiring back there that held up and I've had stuff that had to be replaced.

Check V1 preamp tube first by swapping it with a new tube.

Also, I noticed you have a "distortion" knob. Make sure it's "off" (is there a click/detent?) and that there is no push/pull activation you might have accidentally engaged. Push all knobs inwards to make sure. I'm not familiar with Super Twins but I had a similar feature someone put in my 72 TR.

Remove back tube panel cover, fire up the amp, turn off standby and visually inspect the tubes. You may have one glowing bright red more than the others. Could be a problem tube.

With amp "on" and volume up around 4 maybe, take a plastic pen, pick, or thin wood dowel and gently tap each tube. You may get excess noise from one. That's generally how I would check for microphonic and problematic tubes.

See if any of those things help identify the problem.

My gut instinct is both amps are due for caps, tubes, and complete health check up. But I'm no amp tech. If I had them at a good tech I would have ALL caps and tubes replaced as a preemptive move for reliability. Between caps and tubes on both amps plus the service fee you're looking at probably north of 1k, just a rough estimate. They might hold up for a while with less maintenance, mine did, but aged components start failing under hard use which meant I had issues at a gig or two.

 

[rsm]

Thanks!

The distortion on Amp #2 is off, and it doesn't work at all, which is fine though...could be stuck on, but listening to the built-in distortion on amp #1, it sounds different, like an artificial distortion; amp #2 distortion sounds like natural tube distortion, unlike the built in distortion; and it stays constant at any volume / mv level, the volume gets louder but it's the same distortion.

I'll take a look inside, and swap each tube in order, may be a few days before I get to it, I have to travel for work this week.

Amp #1 needs a recap, but it's only slightly noisy since I replaced all the tubes; and it sounds great, very clean, clear, dimensional.

 

[JohnnyGtar]

My gut instinct is both amps are due for caps, tubes, and complete health check up. But I'm no amp tech. If I had them at a good tech I would have ALL caps and tubes replaced as a preemptive move for reliability. Between caps and tubes on both amps plus the service fee you're looking at probably north of 1k, just a rough estimate. They might hold up for a while with less maintenance, mine did, but aged components start failing under hard use which meant I had issues at a gig or two.

YEP. THIS. 110%!