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Twin Peaks - incredibly loud thumping, much louder than guitar

Started by lincolnic, January 28, 2016, 05:29:00 AM

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Quote from: drolo on February 28, 2016, 08:36:43 PM
About the setting of the bass/treble trim pots, most of the time I leave them fully counterclockwise.

Oh, I forgot to mention -- I actually started out with both of those trimmers fully counterclockwise, and still had the thumping. But I'll definitely set them back that way for further troubleshooting.


Please keep this post going! i have a board set ready to go.
I am wondering if there is a way to put the two boards together temporarily until tested?
What I mean is if you could have a do over how would you do it?


Stumbled across this thread while building my TTT. The clicking was bad on severe and deep shapes.  It occurred when the LED of the vactrol was off.  Didn't matter which type of trem was set.

I even tried turning the current to the vactrols all the way "off".  (BTW, when you say CCW, is that brightest LED or dimmest?)

I finally tried tweaking the offset till it went away.  The only thing is: instead of each test point being half of B1, it's more like 1/3 and 2/3.  Is that ok?

Sent from my SM-G920V using Tapatalk


As long as it got rid of the noise and did not impact the sound negatively, it can only be OK :-)

What moving this bias point from the half voltage does is that one op amp's bias will be offset up or down, while the other one will equally be offset in the opposite direction. One caveat of this is that, the output of the TAPLFO not being centered at half supply, one or the other half of the signal might get clipped. But if by offsetting it slightly you get rid of the ticking it sounds like a good solution.


What about the CCW question: when you say CCW, do you mean that the LED is brightest or dimmest (most or least current)?



Also have ticking problems with a cherry pie build exactly as delyk described above. Used xvive vactrols and nice components through out. The 100nf cap installed. Any new solutions to this? Will decoupling the offset wiper help? I will try jumpering one of the 33ohms as jon patton suggested. Maybe the output of the 78l05 should be more decoupled as well?


I know this is reviving a dead thread, but I have just solved the tick in my build.  My issue was a ticking or thump when in the standard mode on all wave forms when the depth was past 10:00.  I have build the vero version on tagboard and a pcb from delyk (cherry pie trem).  Both had the exact same issue.  I tried many of the suggestions above:
100n cap
jumping 33r resistor
shielding the input and output wire

none of these really worked for my issue.  The one that fixed it was placing a small cap (100pf) across the volume trim.