Anyone know what the mxr suboctave bass fuzz fuzz section is based on?

Looking for it something comparable with treble and bass controls.

Thanks

Just to be clear, you are interested in the fuzz, tailored to the actual bass signal, and not the subctave itself?

Yes.

In my opinion, bass fuzz well done is a relatively low gain Big Muff. I remember a Colorsound bass fuzz that was probably a Big Muff without the second clipping stage.

Are we talking about this..??

Funny parallel BJTs of different h_FEs and V_BEs configuration..

To my (very basic) knowledge, even if there was a need for current sharing (which shouldn't be the case here) it can't be obtained without Emitter ballast resistors..

Can't find any reason other than noise issues prevention..

Quote from: antonis on May 22, 2025, 05:11:32 AMAre we talking about this..??

Funny parallel BJTs of different h_FEs and V_BEs configuration..

To my (very basic) knowledge, even if there was a need for current sharing (which shouldn't be the case here) it can't be obtained without Emitter ballast resistors..

Can't find any reason other than noise issues prevention..

I don't know. Is that the fuzz circuit of the mxr suboctave bass fuzz?

Advertisements say it's a long lost fuzz circuit. Which would lead one to believe that it would be in the vein of a simple fuzz with the added treble and bass controls.

How does a FF with contour, bass, gain, and volume sound with a bass. Excluding input and output cap changes?

I tried finding a clip of a fulltone 69 with a bass without any luck.

Quote from: antonis on May 22, 2025, 05:11:32 AMFunny parallel BJTs of different h_FEs and V_BEs configuration..

I think it is actually a CHOICE of transistor and pin-out.

Quote from: PRR on May 22, 2025, 12:29:52 PMI think it is actually a CHOICE of transistor and pin-out.

Thanks Paul..!!

Didn't notice 3904 pins numeration corresponding to IC transistor array..

Quote from: antonis on May 22, 2025, 05:11:32 AMAre we talking about this..??

Funny parallel BJTs of different h_FEs and V_BEs configuration..

To my (very basic) knowledge, even if there was a need for current sharing (which shouldn't be the case here) it can't be obtained without Emitter ballast resistors..

Can't find any reason other than noise issues prevention..

What is "this"? I mean, sure, it's a Big Muff of some kind, but is the schematic you posted the fuzz circuit from the MXR Suboctave fuzz?

Quote from: Fancy Lime on May 24, 2025, 05:52:29 PMWhat is "this"? I mean, sure, it's a Big Muff of some kind, but is the schematic you posted the fuzz circuit from the MXR Suboctave fuzz?

Not enough controls and no sub octave generator.

The P-channel JFETs look a bit like a modern MXR circuit.   Perhaps the MXR El Grande Bass Fuzz?Although the switch name on the unit is Deep and the switch on the schematic is Sub Boost.   Not up on all the later MXR pedals.   Maybe not the El Grande it's only 3 knob and we want four.  The "sub machine" looks closer for knobs etc.

Quote from: Rob Strand on May 25, 2025, 12:16:05 AM

Quote from: Fancy Lime on May 24, 2025, 05:52:29 PMWhat is "this"? I mean, sure, it's a Big Muff of some kind, but is the schematic you posted the fuzz circuit from the MXR Suboctave fuzz?

Not enough controls and no sub octave generator.

The P-channel JFETs look a bit like a modern MXR circuit.  Perhaps the MXR Le Grande Bass Fuzz?Although the switch name on the unit is Deep and the switch on the schematic is Sub Boost.  Not up on all the later MXR pedals.  Maybe not the Le Grande it's only 3 knob and we want four.  The "sub machine" looks closer for knobs etc.

Quote from: Rob Strand on May 25, 2025, 12:16:05 AM

Quote from: Fancy Lime on May 24, 2025, 05:52:29 PMWhat is "this"? I mean, sure, it's a Big Muff of some kind, but is the schematic you posted the fuzz circuit from the MXR Suboctave fuzz?

Not enough controls and no sub octave generator.

The P-channel JFETs look a bit like a modern MXR circuit.  Perhaps the MXR Le Grande Bass Fuzz?Although the switch name on the unit is Deep and the switch on the schematic is Sub Boost.  Not up on all the later MXR pedals.  Maybe not the Le Grande it's only 3 knob and we want four.  The "sub machine" looks closer for knobs etc.

What I meant was not if it was the whole MXR Suboctave Fuzz but if it was something else that was identical to just the fuzz subcircuit of the Suboctave Fuzz.

Anyway, you were right about it being the El Grande Bass Fuzz. There is a thread on The Other Forum about it with the same schematic. The fourth pot seems to be a trimm pot, according to this here
https://dirtboxlayouts.blogspot.com/2021/03/mxr-el-grande-bass-fuzz.html?m=1

Quote from: Fancy Lime on May 25, 2025, 05:45:36 AMWhat I meant was not if it was the whole MXR Suboctave Fuzz but if it was something else that was identical to just the fuzz subcircuit of the Suboctave Fuzz.

Anyway, you were right about it being the El Grande Bass Fuzz. There is a thread on The Other Forum about it with the same schematic. The fourth pot seems to be a trimm pot, according to this here
https://dirtboxlayouts.blogspot.com/2021/03/mxr-el-grande-bass-fuzz.html?m=1

Good find.  At least we know what it is now.

According to the manual there are two internal settings. SW3 sets the frequency (87Hz/113Hz) and the RP4 trimpot sets amount of boost or cut (upto +15dB) when the deep switch is pressed.  The trimpot should be labelled sub-boost or sub-boost level.  It's definitely not frequency.  The switch SW3 sets the frequency.   It's basically a gyrator based EQ.   

In retrospect sub-boost isn't the right name either.  Maybe just 'deep' or 'bass'.