Ionosphere Fuzz — less bass mod?

[tortoiseshell]

Hello everyone!
A while back, I built an Ionosphere Fuzz pedal — everything was done to the stock specifications, except I followed another user's advice and used a 100pf capacitor in place of the 15nf that's listed in the original schematic (the pedal has more treble this way).

I definitely like the pedal's tone more with this small modification, but it still has much more bass than I want in a dirt pedal. I'm still fairly new to pedal building and modification, and wanted to ask if anyone could advise me on how I could reduce the amount of bass in the circuit? (And actually, is there a way to quickly tell which part of a pedal schematic has to do with a pedal's EQ curve?) Thanks in advance!

 

[jwin615]

See "RC filter"

 

[jwin615]

C6 to 47n-100n would be my first stop, at a quick glance.

 

[Feral Feline]

I'd also see about having a play with C1. Try reducing it from 2µ2 to 1µ and/or make R3 a pot/trimmer to control C1.

Ah, I see that C1 goes to ground, not VREF feeding it. Hmm...


Paging Bass-Controller @HamishR ...

... is there a way to quickly tell which part of a pedal schematic has to do with a pedal's EQ curve?...

Not really, IMO.

Circuits are a balancing act and each stage or grouping of components can have an effect on the overall EQ of a circuit.

For example, some compressors push the treble way up at the beginning of the circuit and then bring the treble right back down to where it was at input — it's a way of lowering the overall noise-floor and minimising "compressor-hiss".

Generally, I want more bass, so the input and output caps are what I look at first, then at coupling caps between stages to see if there are any choke points for bass freqs.

Anywayyyssss, back to that balancing point:

Since it's a high-wire act, when you've reduced the amount of bass in your Ionosphere, you may need to fettle that 100pF cap again or adjust some other part of the circuit to get exactly the tone you're after.