VRH spec Mudbunny has insane gain...

[mgwhit]

I finished a Mudbunny last night with Violet Ram's Head specs and the Mids knob omitted (jumpered).  The gain on this thing is out of control.  I typically get about unity gain with the volume knob set between 8:00 and 9:00.  I'm not really familiar with playing through a BMP, so I don't know if this is typical or not.

Other than that, it's pretty much what I expected -- big, hairy wall of fuzzy distortion -- and there's plenty of usable tones there.  There's just no subtlety whatsoever.

(There's also very little useful space on the Tone knob outside of 11:00 - 1:00, but I understand that's fairly typical and I don't feel like I need it.)

For what it's worth, I ran the specs for each variety through a BMP gain calculator formula, and the VRH should have much more gain than the Triangle and Russians, but less than the Mayo and (obviously) the Creamy Dreamer.

If anyone else with a Violet Ram's Head Mudbunny would like to comment on the gain level I'm getting I would appreciate it.  Maybe there are some voltages I can check on the transistors to see if I'm running hot.  Thanks!

[bigmufffuzzwizz]

This is my favorite circuit so far! I've recently been doing the creamy dreamer mod to the VRH for even more gain(for my doom metal buddies). It should be way over the top, but more like a classic fuzz/distortion sound than the normal muff chunkyness. If you wanna bring it down you can put a pot in series with the input that would be a pre-gain knob. That will set the overall gain and will help with fine tuning the circuit. I've never tried it on a muff but I know it works for the fuzz face. I believe something like a 50kB pot would work well. Try it and tell me how it works for you! I love this circuit sooo much!!!

[mgwhit]

Thanks, bmfw.  I'll interpret that as a "yes, of course it's supposed to be that gainy!" 

For the record, I intended to build a gainy BMP, I just wasn't prepared for the result.  I certainly like it as is (and will probably box it like this), but I'll also probably re-approach this circuit with a breadboard in the future.

Still undecided about applying the Presence/Mids mod.  I've been playing with the Duncan Tone Stack Calculator and I've learned a lot about how to tweak that part of the circuit, but I can't really translate any of that into real tone in my head.  I'll probably end up removing and socketing R18 and C10 this weekend. 

What I will point out is that with the VRH specs there doesn't seem to be that much of a mid scoop to begin with (~5db).  It'll be interesting to see what lifting that will do, but I'm not expecting much.

[Haberdasher]

I was having the same thoughts about my triangle.  I ended up liking it a little better once I used BC549Bs(pins are 180 degrees from the 2N5088s).  The lower gain trannies still get huge, mean and creamy but it isn't quite so over the top.  Anyway, that is something else cheap you could try.

[mgwhit]

Thanks for the recommendation!  Is there any significant difference between the BC549B and the BC549C that Bean mentions in the project PDF?  The Fairchild versions on Mouser use the same data sheet and have almost identical specs.

[jkokura]

HFE is higher with the C. That means more gain, but the difference is scientific, not audible really.

Jacob

[FredGarvin]

For a huge mid boost or scoop replace four parts in total, R18 to 1k5, R19 to 47k, C10 to 22nf, and C11 to 5.6nf. Use a 20kb pot for the mid control.

I used BC549c trannies in my build and I can tell the difference/audible in gain/tone compared to the BC549b.

[mgwhit]

I used BC549c trannies in my build and I can tell the difference/audible in gain/tone compared to the BC549b.

I take it you preferred the higher gain from the C then?

Just for giggles, I swapped in a 100KA for the stock 100KB Sustain pot today.  It does give a bit more useful play on that knob, but it also affects the volume/output much more significantly.  That's not really a problem as I still never felt the need to go past Noon on the Volume control.

Anybody else ever try the audio taper pot on the Sustain control?

[Mike @ Rawkworks]

Chiming in about the presence control...its worth the few extra parts.

[mgwhit]

Chiming in about the presence control...its worth the few extra parts.

Did you go for the full on tone stack overhaul a la FredGarvin or something more subtle?

I've been thinking about subbing in 10nF for C10 and 10K for R18 because (a.) it's easy, and (b.) I've got those parts sitting on my desk right now.  That would give me a similar scoop to what I've got right now with the 25K Presence Pot at minimum, but a flat response with the Presence maxed out.  Here's a graph.  Green is what I've got now (4.7nF C10, 39k R18), Red and yellow are my proposed subs.



I guess I'm just wondering if that will help leads stand out more, or if I need to go whole hog Jack Orman version 2 and get a mids hump in there.

[bigmufffuzzwizz]

I ended up with something similar to Fred Garvin and really enjoyed the added versatility. I didn't change both sides of the tone stack only the treble side (R18,C10). I lowered R18 to about 3.3k and C10 I believe was 22nf. My buddy loves the pedal, he says its so great for leads and just cutting through the mix in general. 

[mgwhit]

Wow!  I really like the mid scoop-to-boost curves those R18 and C10 values produce -- and I'm pretty sure I've got those values on hand, too.  I'm going to try those tonight.  Thank you!

[FredGarvin]

Jack Orman's version 2 tone stack is what gave me the incentive to look further into the mid boost.

I had a friend over recently and he never tried a fuzz pedal before? I called him a freak, he tried my muff pi, and now he's freaking out more, and he wants one. Cool.