Fender Twin-tremolo is weak at 10. not tube. culprit?

rjd2 · Post by **rjd2** » Tue Mar 31, 2009 6:05 am

thats basically the problem. (incidentally, i also get a "popping" sound at the tremolo peaks, as if its not a true sine wave). i couldve SWORN that it used to be a full-on tremolo when at 10, i.e. SILENCE when the sine wave was nulling. now, it never reaches 0db.

i've individually swapped out each of the 6 preamp tubes, its not them. i've checked the RCA jack, its functioning properly. could it be the actual "VIB" pot? i REALLY dont want to lug this boulder to my amp tech, but i guess i will if it needs to be done. im just not sure where to look next. thanks for the help.

Mudcloth · Post by **Mudcloth** » Tue Mar 31, 2009 6:43 am

As far is at being weak when you get to 10, it could be the pot. It may come open at 10. I saw this yesterday at the shop I work at with a brand new pot. It happens.
It wouldn't hurt changing out the pot. Just make sure it's the same value. Also, when you do, remove the old pot from the chassis without unhooking the wires. Then put the new pot in. Finally, hook up the wires one at a time so there will be no chance of mistakenly re-hooking it up wrong.
As far as the popping sound, it could be the plate load resistors on the 12AT7 and 12AX7 tubes. Changing then out from 1 watt to 2 watt resistors may help.
Also, sometimes the caps near the optocoupler pick up the pulse. Try pushing them away from the OC with a a pencil.
Of course, do all of this with the amp off and take all the usual precautions.
Or better yet, if you're at all not comfortable with any part of this, take it to your tech.

rjd2 · Post by **rjd2** » Tue Mar 31, 2009 6:57 am

thanks alot for the advice. im SUPER SUPER careful paranoid when working on tube stuff. try to work with only one hand at a time, if possible.

Scodiddly · Post by **Scodiddly** » Tue Mar 31, 2009 4:14 pm

If it's generally weak, it's probably the optoisolator. At $15 it's cheaper than some of those cryogenically treated tubes you might have been drooling over in the latest issue of "Guitar Amp Boutique Tube Quadriquarterly Journal".

KennyLusk · Post by **KennyLusk** » Tue Mar 31, 2009 4:37 pm

Scodiddly wrote:If it's generally weak, it's probably the optoisolator. At $15 it's cheaper than some of those cryogenically treated tubes you might have been drooling over in the latest issue of "Guitar Amp Boutique Tube Quadriquarterly Journal".

But the Cryo Tubes match up so well with my Cryo Strings

Scodiddly · Post by **Scodiddly** » Tue Mar 31, 2009 4:56 pm

Tremolo ticking... that's usually a different problem.

Here's one webpage, since I couldn't find the one I was thinking about, which talks about that problem:
http://www.regiscoyne.com/tech/tremolo/

rjd2 · Post by **rjd2** » Wed Apr 01, 2009 2:50 pm

thanks, guys. dropped in new pots for reverb and vibrato sections, its sounding GREAT! fixed the clicking, and the intensity issue.

just curious-i should just expect a small amount of hum w/ the reverb all the way up, right? i've recapped the entire amp, and had it retubed/biased a while back, so at this point, i dont know what else it could be....swapped tubes, its definitely not that. not a big deal, its sounding great even with a little hum.

Mach Schnell · Post by **Mach Schnell** » Fri Apr 10, 2009 5:47 am

You run the verb wide open?

Some hum (at that level) would be normal, best way to minimize this is with a good NOS recovery tube (GE/RCA/SYL etc) and make sure that the cables are making good contact with the RCA jacks.

I like a "splash" of reverb (2-2.5), any more than that and you better be playing surf music.

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Fender Twin-tremolo is weak at 10. not tube. culprit?

Fender Twin-tremolo is weak at 10. not tube. culprit?

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