Big Muff "No Diodes" Mod

Thom · Post by **Thom** » Mon May 19, 2008 1:06 pm

If I get mine back off our bass player who borrowed it, and bring it to Doogfest maybe we could do some pre and post mod demo?

Post by **Mike** » Mon May 19, 2008 1:07 pm

Could be a plan!

Sublimedo · Post by **Sublimedo** » Mon May 19, 2008 1:09 pm

I'm clipping. I'm clipping. I'm clippity clipping. clip clip clip clipping.

I think I love the sound of my Big Muff too much to mess with it, but with a couple of switches on there to slap the diodes back on might be a pretty cool prospect to try out this summer.

aen · Post by **aen** » Mon May 19, 2008 1:58 pm

Wierd, dudes. The fuzz I am working on currently has switchable diodes. LEDs actualy. i was hoping htey would light up when you rocked it, but they are just barely noticable.

The wierd part is that it sounds more muffy with the diodes out of the circuit. If you have one on, it osunds more metal-y and sharp, if you have noth on it gets all squashed and disgusting and fender Blender-ish.

Post by **Mike** » Mon May 19, 2008 2:07 pm

aen wrote:Wierd, dudes. The fuzz I am working on currently has switchable diodes. LEDs actualy. i was hoping htey would light up when you rocked it, but they are just barely noticable.

The wierd part is that it sounds more muffy with the diodes out of the circuit. If you have one on, it osunds more metal-y and sharp, if you have noth on it gets all squashed and disgusting and fender Blender-ish.

Hmm.

Where are they placed at the moment? As a clip to ground at the input of an amplifier stage or in controlling feedback of an amplifier stage?

The LEDs will only be having an effect over their threshold (which should be fairly high ~ 1.2V maybe) so that's why the brightness is low - I too though they would be vibey, but I figured it might be limited effect. As for the more aggressive clipping you're hearing, that's quite interesting. If I had a schematic it might help, although I'm a complete newbie at all this guitar electronics stuff, I'm totally learning as I go.

aen · Post by **aen** » Mon May 19, 2008 2:15 pm

I DON'T KNOW. Really, I just lined up LPBs and swapped componenets until it sounded cool. They go from Base to collecter on two transisters a 2n22222 and a 2n3904, I think, the neg. side being at the base. There is a clean LPB in front of those driving the whole operation.

The diodes might be adding more gain, like waytoo much gain, like when you put verdrive on top of distortion and it flubs out.

Post by **Mike** » Mon May 19, 2008 2:17 pm

I think you need to decouple them with a cap if you're going to do that, like this:

aen · Post by **aen** » Mon May 19, 2008 2:20 pm

Oh, I'm satisified with it. It may just be a Fuzz factory killer. Anyway, EHX already makes a Big muff.

http://www.myspace.com/dwarfcraftdevices

"shiva prototype" first couple riffs are undioded. The second set of riffs has one diode on. When it gets pukey, thats both diodes

Post by **Mike** » Mon May 19, 2008 2:23 pm

aen wrote:Oh, I'm satisified with it. It may just be a Fuzz factory killer. Anyway, EHX already makes a Big muff.

I wasn't saying copy the Big Muff, I was just trying to suggest why you might be getting the effect you're describing. If you only have diodes in one direction you're going to only clip one half of the waveform which will definitely introduce harsh and more metallic sounding clipping, and you're also probably going to have an effect on the bias voltage of the transistor stage without the capacitor to decouple things.

But if it sounds good, who cares? The rules are made to be broken after all

Post by **Mike** » Mon May 19, 2008 2:26 pm

Sounds joyfully gated and messy.

I meant to ask, when you prototype, do you use breadboard or just solder stuff up on Stripboard?

euan · Post by **euan** » Mon May 19, 2008 2:47 pm

The Big Cheese uses a transistor with the drain and gate (I think) wired together as a clipper in conjuction with another diode.

aen · Post by **aen** » Mon May 19, 2008 3:10 pm

Mike wrote:Sounds joyfully gated and messy.

I meant to ask, when you prototype, do you use breadboard or just solder stuff up on Stripboard?

I breadboard first, but thats always just a general idea. The breadbord is always roring with noise, and not suepr tight connections, so the real test is with a circuit boarded/boxed thing.

Thanks, BTW, I'm pretty pumped about this thing.

Anyway, big muffs! I like them!

Sublimedo · Post by **Sublimedo** » Mon May 19, 2008 3:21 pm

My BYOC Mighty Mouse has some vibrant surges in its double LED clipping mode. As does the single LED on my dano pastrami overdrive.

Sloan · Post by **Sloan** » Mon May 19, 2008 8:31 pm

Someone should see if this can be done on the Beringher Vintage Fuzz thing.

mewithoutus · Post by **mewithoutus** » Sat May 24, 2008 5:32 am

im putting a two pole six position selector switch in the big muff with LED"s, silicon and germanium didoes to be switchable for both set of diodes. im building it tomorrow, i will post clips and stuff afterwards if anyone is interested.

aen · Post by **aen** » Sat May 24, 2008 5:52 am

Sloan wrote:Someone should see if this can be done on the Beringher Vintage Fuzz thing.

I heard you can! Yo just have to find teh diodes

mewithoutus · Post by **mewithoutus** » Sat May 24, 2008 7:18 am

Ninja Mike 808 · Post by **Ninja Mike 808** » Sat May 24, 2008 9:13 am

Wowsers...

You should really make a demo already.

mewithoutus · Post by **mewithoutus** » Sat May 24, 2008 7:16 pm

i havent done the major mods yet. i will make a demo when ive got it all done. pics tonight!

mewithoutus · Post by **mewithoutus** » Sun May 25, 2008 4:15 am

repost from harmony central effects forum:

okay, heres the inside of the muff before i rewired the rest of it:

heres the first switch, with the diodes:

second switch:

the circuit board close up, showing the stage one clipping section. the two solder pads directly above the empty holes is where the switch is injected into the signal path:

the inside of the muff after i reqired it and did some wire dressing with lacing cord. whoever wired it up at the factory was on peyote:

another inside view:

amp_surgeon already explained what the switches do. i can basically select up to 36 different combinations of clipping diodes. its really cool, and the results are pretty much what i expected.

the silicon diodes have a harder edged, brighter sound. i used 1N4148 fast switching diodes for this point.

the germaniums are NTE109's. they drop 300mV, which is significant, so they are pretty quiet. however, the resulting fuzz is nice and organic, thick, and wooly. im gonna try boosting it with the od3 on this setting to see how it sounds.

the red, yellow, and green LED's drop 1.8, 1.9, and 2 volts, respectively. not a big change, but it seems that the green LED's have a bigger bottom nd. the red LED's actually light up when played, and they clip soonest. i like the sound of the red LED's, loud and cutting. more mids.

and obviously the no diodes selection is just loud as hell.

i am going to experiment with different combinations and report back.

i will do some clips tonight, nothing crazy, just a few comparisons.

for those of you who dont surf HCFX, the switches each have a pair of diodes on each setting, having six setting each. the two switches have the same diodes on both in the same configuration. the point was to be able to combine any two pairs of diodes to change the clipping characteristics. very cool. i recommend this mod to anyone, it really opens up your big muff to a huge palette of sounds. its a little time consuming and may be difficult for the first time modder.