# More bass in Octa Meyer fuzz?



## Moltenmetalburn (May 18, 2020)

The OMF cuts too much bottom end for my liking with extended range guitars.

Any ideas on how I can get more bottom end out of this circuit or can point out the filters to modify?


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## Chuck D. Bones (May 19, 2020)

Do these four things and your bottom end will extend down to 63Hz:
Increase C4 to 1uF
Increase C6 to 100nF
Increase C10 to 100nF
Don't set DRIVE above 8.  C5 is a choke point when DRIVE is dimed.  You'll need 1000uF to squeeze the last drop of bass out of this thing if you have to turn DRIVE up to 11.





Roger Mayer is a smart guy and he tuned this pedal very deliberately.  No telling how good or bad it will sound with these mods.  You might be better off with a BLEND control à la the Parenthesis. Just sayin'.


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## Moltenmetalburn (May 19, 2020)

Thanks Chuck!

Hmmm that is something to consider isnt it?!  that a clean blend may be a better choice after all. I do understand it could sound like ?.

does the circuit invert the signal? Maybe Ill try a jfet buff n blend style blend instead.

is there some way to limit the drive to prevent the “choke”? What happens when set above 8?


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## Chuck D. Bones (May 19, 2020)

What I'm saying is don't turn the DRIVE up past 8 because no capacitor will be big enough for C5.  If you need more gain, put a booster in front.

OK, the reason I'm ? at your last question is an octave-up circuit inverts and doesn't invert.  It does both at once, that's how it makes the octave-up.  What that means for you is that you never have to worry about inversion with an octave-up circuit.

To get a little more technical, the concept of relative phase only has meaning when the two waveforms you're comparing are the same frequency. Change the freq with an octave-up, octave-down or a pitch bender and phase goes out the window.

Give the buff-n-blend a try, it may get you where you wanna go with the least amount of trouble.  If you don't already own a Parenthesis, you might consider building one because it sounds like it might be just what you're looking for.


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## Moltenmetalburn (May 19, 2020)

Chuck D. Bones said:


> What I'm saying is don't turn the DRIVE up past 8 because no capacitor will be big enough for C5.  If you need more gain, put a booster in front.
> 
> OK, the reason I'm ? at your last question is an octave-up circuit inverts and doesn't invert.  It does both at once, that's how it makes the octave-up.  What that means for you is that you never have to worry about inversion with an octave-up circuit.
> 
> ...


? I realized that after posting and edited my comment. 1000uf lol.

Great, awesome technical explanation, always excited to better understand these effects. will have a look at that as well. Thanks again. ?


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## Chuck D. Bones (May 20, 2020)

Moltenmetalburn said:


> is there some way to limit the drive to prevent the “choke”? What happens when set above 8?



Best way to limit the DRIVE setting to 8 is to exercise a little restraint.  What happens above 8 is the gain continues to increase in the midrange, but the bass and treble stop increasing.  It's inherent in the design, and for good reason.  You need pure tones to make good octave-up.  Too many harmonics going into the octave stage makes a ring-modulator sound; lots of dissonant tones and noise.  Maybe that's the sound you're after.  Apparently, that is not what Roger Mayer intended.


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