Eric Clapton Mid Boost with mods

[Elijah-Baley]

Hello,
I built it using this stripboard layout.

Fender Eric Clapton 25db Mid Boost

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tagboardeffects.blogspot.com

The circuit is pretty much the same as this schematic, except for the RPD resistor. I also added the switch, and the transistors are the same.




I tried a couple of extra mods and then incorporated them into the pedal using two switches.
One in particulare has a little problem. The mod uses a fixed 3.3nF capacitor for C8 to get a low-cut mode. The switch adds an 18 nF capacitor in parallel, bringing the total capacitance to about 22nF, which is the original value.
But when the switch add the 18nF capacitor I get a pop. It's not too annoying, and I've experienced similar issues with other mods of this kind in my pedal, but I'd like to find a way to fix it.

Adding a 1M resistor between C8 and R8 across the ground didn't solve the problem.

Thanks for your help!

 

[lowpitch]

You need to make sure both sides of your 18n cap sit at the same potential as each side of C8 to minimize pop. One way you could achieve that: keep one leg of the 18n cap always connected to the C8/R9 node, the other leg goes to the outer lug of the switch. Then attach the middle lug of the switch to the C8/R8 node and add a 1M to 10M resistor from the outer lug to the middle lug of the switch. Through the resistor the 18n cap now always sees the same voltage as the R8/C8 node, regardless of switch position, hopefully minimizing pop.