"Muff Minor" - the wheel re-invented?

[frequencycentral]

I'm messing about with the Big Muff circuit on my breadboard right now. This is something that came out of it that I thought was really cool sounding. It's the second stage of a Big Muff with a couple of component values changed and a pot added to control the diode clipping. It goes from slightly dirty boost through to nice gritty clipping. I've tried it with BC208, BC107, BC238 and BC547, sounds nice (nasty) with all of them. Si diodes are good, Ge create too much volume drop really.

I'll wait for someone to pipe in and tell me that all I've done is re-invent the "Blah Blah Whatever Fuzz", in the meantime I'm having a little dirty fun with it.

[Mark Hammer]

A nice beginner circuit!

The Sola Jumbo Tone Bender was essentially a Big Muff Pi without clipping diodes in the 2nd transistor stage.   Over the years, I've suggested to people who were looking for interestng mods to their basic BMP build to simply lift the diode path on stage 2, but this seems like it might yield more interesting flavours by varying the degree of clipping, vs boosting produced in that 2nd stage.

Nice work.

[frequencycentral]

Thanks Mark, yeah it would make a nice beginner circuit wouldn't it. I was breadboarding really to see what mods I will make to a BM when I eventually get round to building one, I really wanted to try switchable Si/Ge diodes, but I've ruled that out now due to the volume drop with Ge, though I may add the pot I used here to reduce the clipping. I also wanted to see what difference changing some component values would make, and generally understand what does what in the BM. This is just a bit of fun that came out of it.

[biggy boy]

Question: Oh boy here we go with the questions again
The pot you added, It only effects the degree of clipping right? Not the gain of that stage.
Does it change the diodes clipping headroom?

Glen

[frequencycentral]

The pot you added, It only effects the degree of clipping right? Not the gain of that stage.
Does it change the diodes clipping headroom?

Yes it affects the degree of clipping. Clipping does reduce volume by it's very nature, so the more clipping is dialled in the less volume, so increasing the clipping requires you to increase the output volume (Boost pot) to maintain the signal level. The Clip pot reduces the amount of signal reaching the diodes, so with the pot at maximum resistance the diode have very little to clip, so the signal is 'almost' clean. The circuit can provide simultaneous clipping and boost with both pots maxed out.

[biggy boy]

Thanks Rick
By the way I'm still working on that Tremolo Issue I'm having with my Valuecaster setup. I'm going to try a different aproach.

Mark!
How would this setup on a big M sound compare to the Voodoo distortion mod you helped me with last week.
Would it sound much the same when they are both dialed up to max gain?
Just wondering if it would be worth making a big muff, but if it sounds the same then I wouldn't see the point in making it, there too many other porjects one could work on.

[frequencycentral]

By the way I'm still working on that Tremolo Issue I'm having with my Valuecaster setup. I'm going to try a different aproach.

It must be the cheap 'value' tubes you're using.......?

[B Tremblay]

[Mark Hammer]

Thanks Rick
By the way I'm still working on that Tremolo Issue I'm having with my Valuecaster setup. I'm going to try a different aproach.

Mark!
How would this setup on a big M sound compare to the Voodoo distortion mod you helped me with last week.
Would it sound much the same when they are both dialed up to max gain?
Just wondering if it would be worth making a big muff, but if it sounds the same then I wouldn't see the point in making it, there too many other porjects one could work on.

The secret to the BMP sound is that it is clipped twice, but the first clipping is reasonably significant.  Enough that the second clipping imposes almost a fixed signal level with very little dynamics.

Is adjustment of the amount of clipping in the first stage going to be noticeably different from simply adjusting the "Sustain" control?  I don't know.  On the other hand, if you were to install a bypass cap on the Sustain pot, such that turning down the Sustain would still result in potentially high drive from the upper mids and above (though lower drive from the bass end), that could be interesting.  Varying the base-to-collector resistor in Rick's design, in tandem with a compensated ("bright cap") input sensitivity pot, might offer greater sonic variety for a modest investment.  For the moment, I'll suggest 2200pf as a starting value for the compensating cap, and let your easrs dictate where to proceed from there.

[frequencycentral]

It's worth playing about with the value of the 47K resistor in this circuit. Removing it completely gives loads more gain, but you lose the clean boost facility. Maybe I'll try lowering the value (the BM is 33K) or making it switchable. It does look quite like the though Muffer doesn't it?

[Ben N]

Yup--aside from clip control, and the age-old coupling cap question: 1uf or 0.1uf? Look, Jack basically presented this as a useful snippet from an existing design, so I don't think there is any real question of originality, so no reason you shouldn't come up with a few useful tweaks around the edges.

[sean k]

Reminds me of this... which I really like.

[bluetubes]

Yes it affects the degree of clipping. Clipping does reduce volume by it's very nature, so the more clipping is dialled in the less volume, so increasing the clipping requires you to increase the output volume (Boost pot) to maintain the signal level. The Clip pot reduces the amount of signal reaching the diodes, so with the pot at maximum resistance the diode have very little to clip, so the signal is 'almost' clean. The circuit can provide simultaneous clipping and boost with both pots maxed out.
[/quote]

Is the ratio of gain to clip close enuff that this could this be handled with a dual ganged pot to keep the signal steady?

[frequencycentral]

Is the ratio of gain to clip close enuff that this could this be handled with a dual ganged pot to keep the signal steady?

Well firstly, the ratio of that 'Clip' pot differs with Si vs Ge diodes. So it is diode dependent. I didn't consider it a problem that changing the Clip pot requires changing the Boost pot, as it's pretty universal in dirt pedals that an increase in the gain control will require a decrease in the volume control to maintain unity. I figured it would be something that would be set and forget as guitarists with multiple dirt pedals tend to leave them at the preferred settings and use different pedals for different amounts/shades of dirt. 

[azrael]

Did you try using 4 Germanium diodes, instead of two? That should up the output.

[frequencycentral]

Did you try using 4 Germanium diodes, instead of two? That should up the output.

I never did. I presented this idea as a circuit snippet, and incorporated the clipping pot into a BM I built recently. I'll breadboard it up again and check it out with 4 Ge as you suggest, it's easy and fun to breadboard!

[biggy boy]

Did you try using 4 Germanium diodes, instead of two? That should up the output.

  it's easy and fun to breadboard!

Yikes breadboarding scares me!!
I find it too easy for me to get wires crossed and parts in the wrong place when I breadboard.
I get myself all confused, then I spend lots of time trying to figure out why it doesn't work.
I tend to just build known working circuits. I'll mod that circuit to my liking or leave it as is.
I then go right to a pcb and skip the breadboard stage. If it works great if it doesn't then I set it aside. I have a small pile of boards in my basement 

[azrael]

Cool, I tried it today, and It gets nasty and thick, kinda like the fuzz section of a Brassmaster! I likes.

[Derringer]

I'm messing about with the Big Muff circuit on my breadboard right now. This is something that came out of it that I thought was really cool sounding. It's the second stage of a Big Muff with a couple of component values changed and a pot added to control the diode clipping. It goes from slightly dirty boost through to nice gritty clipping. I've tried it with BC208, BC107, BC238 and BC547, sounds nice (nasty) with all of them. Si diodes are good, Ge create too much volume drop really.

I'll wait for someone to pipe in and tell me that all I've done is re-invent the "Blah Blah Whatever Fuzz", in the meantime I'm having a little dirty fun with it.

probably a stupid question and if it is I plead ignorance

but FC ... have you tried this configuration with a mini tube? Did it work well / poorly ?

I'd imagine you'd have to take the BM route and AC couple the diode(s) to the anode to keep the HV off the grid

[frequencycentral]

probably a stupid question and if it is I plead ignorance

but FC ... have you tried this configuration with a mini tube? Did it work well / poorly ?

I'd imagine you'd have to take the BM route and AC couple the diode(s) to the anode to keep the HV off the grid

I never did.........do you think I should? I think I'll have to try it now! And no I don't think its a stupid question - I'm curious now!