Spit take

[Mark Hammer]

Many years before many of you here were born, I was I a band and we were at a gig.  For reasons I don't quite remember or understand, that evening I had the use of two EHX Muff Fuzz boxes.  At that time, they weren't pedals, but boxes with a 1/4" plug on them that you stuck into the guitar output jack.  I plugged two in series so that my guitar looked like it had a baby's leg sticking out of the pickguard.  But the sound was magical, maybe because of the cinder-block gymnasium we were playing in.

Flash ahead almost half a century, and EHX has a pedal called the Double Muff that essentially duplicates what I had sticking out of my guitar.  So I built myself one.  In typical me fashion, I wasn't content to leave things be, and threw on some mods.

The Muff Fuzz is essentially a silicon Fuzz Face.  So is the ZVex Woolly Mammoth.  One of the things I like on the Mammoth is the "Pinch" control which varies the feedback resistance from Q2 emitter to Q1 base.  I have implemented it on a couple of fuzz builds that roughly conformed to the FF design.  When the feedback resistance gets large enough, the resulting sound starts to spit and get gated.

On my Double Muff build, I made the gain on the first Muff variable, and left the gain on the second one fixed.  But I installed a 3-position "choke" switch that selected between an additional 200k in series with the stock 100k, an additional 120k, or no added resistance.  Adding resistance beyond the stock 100k increases the "sizzle" of the unit.  But here's what prompted this thread.  Getting spitty gated sounds depends on how hard the first Muff pushes the second.  If I back off on the output of the first stage, the second stage spits real good.  If the output of the first stage is hot enough, though, the total feedback resistance in the second stage doesn't seem to matter.

Why is that?

[Fancy Lime]

So, just to make sure I got this right: The negative feedback "choke" switch is on the second muff only, right?

How about this for a theory.
Case 1: Output of Muff1 is low. In this case Q1 of Muff2 does not see excessive input and does not distort much. The resistance in the negative feedback effectively controls overall amplification in Muff2 and hence the clipping of the transistors. in the end, the pinch control is just a different kind of gain control with different effects on the impedance than source resistor bypass gain, isn't it.

Case 2: Output of Muff1 is high. Now Q1 of Muff too is always being blasted, transistor-clipping in Muff2 happens before Muff2 even amplifies. Hence the diminished influence of the feedback loop.

Does that make sense? Just writing off the top of my head here. Anyway, very interesting take on an über-fuzz. Looking forward to the final result.

Cheers,
Andy

[Kipper4]

Hey Mark.
Are Q1 & 2 at the bottom of the page.
My eyes ain't as good as they used to be.
Thanks.

[Mark Hammer]

Yes.  I had posted a drawing of what I did under a similar-themed thread a few months ago, but that was before Photobucket went all Shkreli on us, and whatever I had posted here could not be linked to anymore.

The mod can be applied to any Q1/Q2 pair in a basic Fuzz Face configuration.  I elected to apply it only to the second Muff Fuzz in the cascaded pair.  The first one has variable gain, variable clipping and output level.  The second one has the "choke" function, and master volume.  As in the stock Double Muff, the output level of the first one acts as the intensity" or "push" for the 2nd one.  Lastly, I have a 3-position master tone switch.

I really do have to make a video or something to illustrate it, because there is an enormous degree of sonic flexibility.  EHX made the conversion from one to two cascaded Muffs a slide switch.  I built the thing into a 1590BB and installed a second stompswitch, so that the user could go from clean, to mildly overdriven, to serious fuzz, under foot control.  Combine the two Muff settings just right, and it implodes.  The time it takes to recover from the implosion is a function of the feedback resistance in that 2nd Muff.  With 100k, little if any implosion.  With 120k+100k, medium recovery implosion.  With 200k+100k there is a long recovery implosion. The implosion can sound almost like a reverse-delay effect sometimes.

[Fancy Lime]

Hey Mark,

that implosion thing sounds a bit like the duck and swell effect I got on a souped up jordan bosstone variant with a sag control. But only at very substantial gains. I've been trying to get this at less extremely distorted sounds but, alas, never succeeded. Do you get it at "reasonable" gains?

Cheers,
Andy

[Kipper4]

I really need to fix my fuzz factory..
Love the subject name btw.

[j_flanders]

I have that implosion+recover thing going on in my modded Pathfinder 10 (ss amp) but only when gain is maxed out. I'll have to check which mod is actually responsible for this peculiar effect.

Not to derail the thread, but by coincidence I have had the original schematic (of which Mark posted the shrunken version) open on my PC the past few days to figure out why the Double Muff manual states:

MUFF 2:  Sets the output level for the first Muff in Double mode. In Single mode this knob is inactive.

while it clearly acts as a tone control.

[Mark Hammer]

I uploaded the file in WMV format so I gather not all browsers can view it.  If anyone knows of a free WMV to MP4 convertor I can use (that doesn't stop at 1/3 of the file in the free version), I can try and upload it in a more universally accessible form.

The amp is just a plain vanilla Fender Champion 110 (which is also a Fender Frontman 25R).

I realized I didn't illustrate the spitty sounds very well.  I'll try and get another video of that mode together later this week.
If you can find a 2nd hand Double Muff on CRaigslist, Kijiji, or whatever, for a decent price, pick one up. The Nano issue in the 1590B enclosure doesn't provide as much room for mods, but is easier to machine.  The earlier-issue folded-steel case is harder to machine, but has a lot more room for mods.

[PRR]

> a free WMV to MP4 convertor I can use (that doesn't stop

No idea about your muffs. However I do have a clue on your secondary problem.

First: YouTube will convert your file to "their" format, so "all" can play it (if they can play any YouTube at all). I think the delivery format has changed in recent years, with the decline of Flash and the rise of newer formats in-browser. Whatever: if they can see kitten videos, they can see your muffs.

For the larger question:

http://video.online-convert.com/convert-to-mp4

This has converted MOV files from an old camera to MP4 for my Android. Perfectly free. Twice fast, once very slow (may have been a bad connection). While not WMV, I see they have another converter TO the WMV format, so I assume the to-MP4 converter can take a WMV. (They say it accepts PowerPoint, which isn't quite a video.) I have NO idea how they fund this service. Ah-- I see that before you get to the free service, you get loud ads for downloadable converters. Be wary. I also accept that they could keep a copy of my video and use it for their own ends. (My videos were dog-barf for vet review, no cash there).