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Sidney Vicious · November 15th, 2006, 11:17 PM

I have a very nice brown Princeton - but the amp "thumps" when the tremelo is engaged and intensity is at 5 or above -

What causes that? How can I silence it? As it is, it renders the tremelo function practically useless 'cause of that thump thump thump in any silent moment -

Thanks

telecaster69 · November 15th, 2006, 11:21 PM

might be a lot of low end coming out of the tremolo..could be a wiring short from the tremolo knob...is the tremolo knob sound like its a dirty pot?

Sidney Vicious · November 15th, 2006, 11:25 PM

Nothing to indicate a dirty pot - like a scratchy static sound? - no. - it's a steady thump thump thump in time with the speed setting when no note is being sounded -

telecaster69 · November 15th, 2006, 11:29 PM

did you try turning down your low end on your amp? Is it more of a sound coming from the speaker or maybe the hardware making the sound like something inside hitting something else?

Sidney Vicious · November 15th, 2006, 11:36 PM

It is definitely coming from the speaker - it is an audio signal in time with the speed setting that shows up with the intensity being increased - it is something in the tremelo circuit -

Joe-Bob · November 16th, 2006, 12:34 AM

This is actually a common problem. Sorry, but I don't know what causes it.

Dacious · November 16th, 2006, 02:27 AM

If you haven't changed the preamp board 25/25 electrolytics ever, it's likely to be one of them. Leaking bass to ground. Also the cap on the bias circuit.

Cantom · November 16th, 2006, 08:14 PM

Check out " A DESKTOP REFERENCE OF HIP VINTAGE GUITAR AMPS" by Gerald Weber of Kendrick Amps. He discusses this problem in his Q & A chapter pages 222 - 224. I had one come into my shop about 12 years ago and I was able to minimize the problem but not get rid of it completely. I think I replaced a cap but can't be sure until I find my shop journal. I'll look for it tomorrow. I just moved a while back and am still trying my old shop stuff.

thegerm · November 17th, 2006, 10:58 AM

I recently recapped my 6G2 princeton and swapped one of the three caps in the tremolo circuit to slow the speed down a little. It sounded great and totally quiet but the other day i noticed it was thumping in time with the speed setting. I checked around on the ol' web and read the output tubes might have gone out of bias with each other and suggested swapping the 2 power tubes around in the sockets.
I did and now the trem is back to being quiet except the slight rising and falling of the single coil noise. And that is with my ear up to the speaker. The thump is gone.
You might try that it won't cost you anything.

Sidney Vicious · November 17th, 2006, 01:53 PM

Thanks for all input -

I will start with that "swapping power tubes around" idea - cheap (LOL) and even I can do it -

TieDyedDevil · November 17th, 2006, 05:26 PM

Thumping is an inherent problem in amps (like the brown Princeton) that use bias-vary tremolo. Closely-matched power tubes can help to reduce the thumping.

CancerLeoCam · November 17th, 2006, 06:47 PM

Quote:

Originally Posted by TieDyedDevil

Thumping is an inherent problem in amps (like the brown Princeton) that use bias-vary tremolo. Closely-matched power tubes can help to reduce the thumping.

I disagree..My "G" Reverb Amp has bias-vary tremolo and does NOT thump.

November 15th, 2006, 11:17 PM	#1 (permalink)
Sidney Vicious Tele-Afflicted Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 1,736 24 Photos	Tremelo thumping sound cause? I have a very nice brown Princeton - but the amp "thumps" when the tremelo is engaged and intensity is at 5 or above - What causes that? How can I silence it? As it is, it renders the tremelo function practically useless 'cause of that thump thump thump in any silent moment - Thanks

November 15th, 2006, 11:21 PM	#2 (permalink)
telecaster69 Tele-Meister Join Date: Aug 2006 Location: Chico, CA Age: 35 Posts: 261	might be a lot of low end coming out of the tremolo..could be a wiring short from the tremolo knob...is the tremolo knob sound like its a dirty pot? __________________ Taylor 310 Acoustic with LR Baggs ibeam. Gold Tuners with Ebony buttons 2004 Telecaster w/hotrails, lckng tuners Fender Powerchorus Amp 2x12" Aphex Aural Exciter pedal HBE Big D distortion pedal.

November 15th, 2006, 11:29 PM	#4 (permalink)
telecaster69 Tele-Meister Join Date: Aug 2006 Location: Chico, CA Age: 35 Posts: 261	did you try turning down your low end on your amp? Is it more of a sound coming from the speaker or maybe the hardware making the sound like something inside hitting something else? __________________ Taylor 310 Acoustic with LR Baggs ibeam. Gold Tuners with Ebony buttons 2004 Telecaster w/hotrails, lckng tuners Fender Powerchorus Amp 2x12" Aphex Aural Exciter pedal HBE Big D distortion pedal.

November 16th, 2006, 12:34 AM	#6 (permalink)
Joe-Bob Poster Extraordinaire Join Date: Sep 2004 Location: Dallas, Texas Age: 47 Posts: 5,531	This is actually a common problem. Sorry, but I don't know what causes it. __________________ Why didn't the Psychic Network already know I was gonna call?

November 16th, 2006, 02:27 AM	#7 (permalink)
Dacious Friend of Leo's Join Date: Mar 2003 Location: Godzone Posts: 2,786 35 Photos	If you haven't changed the preamp board 25/25 electrolytics ever, it's likely to be one of them. Leaking bass to ground. Also the cap on the bias circuit. __________________ My other Telecaster is a Thinline The Tele Bible, Ch 1, v 10 Love thy Telecaster, covet not thy neighbour's Strat!

November 15th, 2006, 11:25 PM	#3 (permalink)
Sidney Vicious Tele-Afflicted Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 1,736 24 Photos	Nothing to indicate a dirty pot - like a scratchy static sound? - no. - it's a steady thump thump thump in time with the speed setting when no note is being sounded -

November 15th, 2006, 11:36 PM	#5 (permalink)
Sidney Vicious Tele-Afflicted Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 1,736 24 Photos	It is definitely coming from the speaker - it is an audio signal in time with the speed setting that shows up with the intensity being increased - it is something in the tremelo circuit -

November 16th, 2006, 08:14 PM	#8 (permalink)
Cantom Tele-Meister Join Date: Oct 2006 Location: Ontario, Canada Posts: 242	Thumping sound Check out " A DESKTOP REFERENCE OF HIP VINTAGE GUITAR AMPS" by Gerald Weber of Kendrick Amps. He discusses this problem in his Q & A chapter pages 222 - 224. I had one come into my shop about 12 years ago and I was able to minimize the problem but not get rid of it completely. I think I replaced a cap but can't be sure until I find my shop journal. I'll look for it tomorrow. I just moved a while back and am still trying my old shop stuff.

November 17th, 2006, 10:58 AM	#9 (permalink)
thegerm TDPRI Member Join Date: Sep 2006 Location: AZ Posts: 17	I recently recapped my 6G2 princeton and swapped one of the three caps in the tremolo circuit to slow the speed down a little. It sounded great and totally quiet but the other day i noticed it was thumping in time with the speed setting. I checked around on the ol' web and read the output tubes might have gone out of bias with each other and suggested swapping the 2 power tubes around in the sockets. I did and now the trem is back to being quiet except the slight rising and falling of the single coil noise. And that is with my ear up to the speaker. The thump is gone. You might try that it won't cost you anything.

November 17th, 2006, 01:53 PM	#10 (permalink)
Sidney Vicious Tele-Afflicted Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 1,736 24 Photos	Thanks for all input - I will start with that "swapping power tubes around" idea - cheap (LOL) and even I can do it -

November 17th, 2006, 05:26 PM	#11 (permalink)
TieDyedDevil Tele-Meister Join Date: Sep 2006 Location: Portland, OR Age: 55 Posts: 224	Thumping is an inherent problem in amps (like the brown Princeton) that use bias-vary tremolo. Closely-matched power tubes can help to reduce the thumping.

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