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EGGHEAD bass trim pot?

Started by MIM#1, January 03, 2013, 11:10:38 PM

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MIM#1

Hi, just put my EGGHEAD in a 3in1 pedal sandwiched between a RUNT and FATPANTS and I'm loving it [Thanks Mr. Bean for the EGGHEAD!]
I have one question, the 'Barber' version of this circuit has a bass trim pot and I feel that would be a usefull addition. Which resistor would target this so I could swap it out with a trimmer?


By the way, I'm running my RUNT at 18v from the FATPANTS and its the best sounding RAT I've owned!  8)

MIM#1

Bumping for a reply. In the mean time heres my 3in1 F.P>EH>RUNT  :)


MIM#1

One more bump as I'd still like to adjust the bass content with a trim pot,is it possible?
Still loving the Egghead BTW! 8)

madbean

From what I gather from the gut shot I saw, the bass trimmer is done in conjunction with a 68n cap in the second stage of the op-amp. Take a look at the "Sparkplug" schematic and you will see a method to do this. You would need to remove C4 and R6 from the Egghead PCB and wire the pads to a bit of perf or vero, then integrate the bass control on there as well. So, it would be two caps in series and a resistor and trimmer in series, then the junction of the two caps connects to the junction of the resistor and trimmer.

stevewire

I am trying to wrap my head around this.  Could anyone lay this out?  I am having trouble visualizing it.