ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

Ugly pop

:

11/5/1999 6:13 PM

Say 'pagers, I have a problem with a pedal i built. It is a EH Hogs foot clone which a useful pedal in my bass world. Darn thang pops pretty loud sometimes when i switch it on or off, sometimes much louder than other times. This happens usually when the pedal is being turned off after being on for a part of a song (and has been on for 20 seconds or more. I assume this has to do with DC buildup in the circuit but as i understand it the input and output caps should keep this from happening. Both are 3.3uf caps positive end towards the circuit.
Have any of y'all had this problem? Fixed it? Can't switckh on beat every time....

Ad.

11/5/1999 6:32 PM
Gus	do you have pulldown resistors on the in/out caps. they "bleed" off the charge in the caps if adding pulldowns does not help maybe you have leaky Electro's.

11/5/1999 7:07 PM
Adrian	There is a 43k res. to ground after the input cap and I patched in a 1m res. after the output cap, which didn't seem to change anything. Are these the right locations, generally speaking? I plan to parallel the caps in the circuit and test for leakage that way. Thanks, Gus.

11/5/1999 7:34 PM

quote:
"There is a 43k res. to ground after the input cap and I patched in a 1m res. after the output cap, which didn't seem to change anything. "

You need a 1M to ground BEFORE the input cap to drain off the charge. As I recall this circuit, the 43k is connected to the base of the transistor which is biased to a dc operating point. Almost all electros have high leakage and the 1M will help minimize the pop from the charge that is building up.

regards, Jack

11/5/1999 7:54 PM
Adrian	Thanks Jack! You have a pretty sharp memory there , cap'n.

11/5/1999 11:05 PM
Coen	Adrian, I have the same problem with ALL my pedals except the fuzz......it pops and pops....sometimes loud, sometimes acceptable and I still haven't found a solution. It drives me crazy. Most of the pedals are TS based FX. I used Electro's. Maybe I should change 'm for reg caps. If you find out anything, please let me know. Have a nice day, Coen

11/5/1999 11:08 PM
gus	Are you using the cheap MCM type switches they pop after time even with pulldown resistors

Page 1 of 2