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DIY Stompboxes => Building your own stompbox => Topic started by: bthm3288 on November 19, 2022, 11:29:25 AM

Title: tone control for delay fx loop
Post by: bthm3288 on November 19, 2022, 11:29:25 AM

I use a delay pedal that has an effects loop (memory man tap tempo).. I currently run a boss eq pedal in the loop, which allows me to tailor the eq of the delay repeats (this does not affect the dry signal).

Since I only ever use the eq pedal to occasionally cut the high end of the repeats, I would like to use a passive tone control in place of the boss eq, if possible.

Any advice on how to wire up the tone control would be much appreciated.. I'm familiar with wiring guitar tone pots but I need some input on the value and taper of the pot, value of the cap, and what the best way to wire up the lugs might be.

thanks!!






Title: Re: tone control for delay fx loop
Post by: antonis on November 19, 2022, 12:54:33 PM
What is the drive stager output impedance and what is the driven stage input impedance..??

If you aren't aware of those values, use a dual op-amp as input - output buffer and implement any R/C values you like..
Title: Re: tone control for delay fx loop
Post by: bthm3288 on November 19, 2022, 01:55:28 PM

thanks antonis for your reply. I'm hoping to use a passive solution.. I'm checking out the stupidly wonderful tone control which looks like it might be a good solution..
Title: Re: tone control for delay fx loop
Post by: antonis on November 19, 2022, 03:17:42 PM
Quote from: bthm3288 on November 19, 2022, 01:55:28 PM
I'm hoping to use a passive solution..

Nothing more plain than a series pot (wired as variable resistor) and a shunt cap..
You might need an extra series resistor for setting the upper corner frequency (for pot fully shorted)..
Pot + resistor values should be a compromise between as low as possible for the least signal attenuation (voltage dividing effect in conjunction with next effect input impedance..) and as high as possible for the least driver output loading (effectivelly set in parallel with previous effect output impedance via shunt cap)..
(e.g. for Zout = 100R and Zin=100k, a 2k value should be "ideal"..)