TheMadCap Posted June 29, 2009 Share Posted June 29, 2009 I have a 1997 Fender Twin (evil twin, red-knob) with the original tube set. Yesterday I noticed that the reverb was only working on one of the three channels. Upon further investigation, it appears that one of the power tubes has died, as I can detect only the faintest glow (may be reflecting from the other tubes). My question is how much credance do you give the notion of replacing the entire set with a fresh, matched set? I would prefer to replace only the bad tube, which might also allow me to skip the bias adjustment step as well. What say you all? Link to comment Share on other sites More sharing options...
WVUFootball29 Posted June 29, 2009 Share Posted June 29, 2009 Nothing better than a nice Fender tube...cept maybe a Vox tube. Anyways, what I would do here is just replace the burnt out tube with an exact replacement and see how it sounds. If it works/sounds like it should, good deal, if not, you're going to have to go through the whole replacement process. Chances are, as long as you use the same tube and give it a little burn in time, you'll be just fine. Link to comment Share on other sites More sharing options...
DC Tom Posted June 29, 2009 Share Posted June 29, 2009 I have a 1997 Fender Twin (evil twin, red-knob) with the original tube set. Yesterday I noticed that the reverb was only working on one of the three channels. Upon further investigation, it appears that one of the power tubes has died, as I can detect only the faintest glow (may be reflecting from the other tubes). My question is how much credance do you give the notion of replacing the entire set with a fresh, matched set? I would prefer to replace only the bad tube, which might also allow me to skip the bias adjustment step as well. What say you all? Tubes are "phased", in that they have to be precisely "twiddled' (a technical, EE term) and balanced to get the perfect sound. This involves a serious investment of time and at least a good quality voltmeter (though I myself would prefer an oscilliscope). Even with a brand new matched set, you'd still have to do this. So unless you're a pro-level musician (or just like to spend money like one, like the guy a few desks down from me who just did this last week) who intends to go through all that micro-adjustment...just replace the dead one and live with it. Link to comment Share on other sites More sharing options...
DrFishfinder Posted June 29, 2009 Share Posted June 29, 2009 I have a 1997 Fender Twin (evil twin, red-knob) with the original tube set. Yesterday I noticed that the reverb was only working on one of the three channels. Upon further investigation, it appears that one of the power tubes has died, as I can detect only the faintest glow (may be reflecting from the other tubes). My question is how much credance do you give the notion of replacing the entire set with a fresh, matched set? I would prefer to replace only the bad tube, which might also allow me to skip the bias adjustment step as well. What say you all? If you've got the jing, I'd do 'em all. The problem with putting just one tube in is that you wouldn't be able to tell the difference with respect to a matched set. Ears can play funny tricks on you. They can convince you that something sounds good until you hear what REALLY GOOD sounds like. Like Laney amps! Link to comment Share on other sites More sharing options...
yall Posted June 29, 2009 Share Posted June 29, 2009 Wear gloves. You don't want grease on the tubes. Also, get GrooveTubes if you end up replacing them all, and make sure to get them biased. You probably will notice a slight sound difference if you don't. Link to comment Share on other sites More sharing options...
TheMadCap Posted June 29, 2009 Author Share Posted June 29, 2009 Thanks gents. Turns out, a guy who used to work here is the amp guru, as in, he's worked on these things since the early 60's. He's retired now and works out of his house. He says as long as there isn't something more serious burned out, the four output valves with biasing will run me ~150 bucks. Can't beat that with a hammer... Link to comment Share on other sites More sharing options...
The Dean Posted June 29, 2009 Share Posted June 29, 2009 Tubes are "phased", in that they have to be precisely "twiddled' I twiddled my tube last night. I don't know how precise I was, but the end result was quite pleasing. Wait...I don't have an amplifier... Link to comment Share on other sites More sharing options...
DC Tom Posted June 29, 2009 Share Posted June 29, 2009 Wait...I don't have an amplifier... Talk to your doctor, he can get you one. Link to comment Share on other sites More sharing options...
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