RNFR - Green Bomb Fuzz

tasteless · Post by **tasteless** » 01 Dec 2010, 15:34

Hey RNFR,
I just wanted to express my appreciation for this - I curiously knocked one together a couple of days ago and I've just been having Soooo much fun !

WHO KNEW SILICON COULD SOUND SO GOOD ?
I have'nt played this much guitar for months.
Cheers.

RnFR · Post by **RnFR** » 01 Dec 2010, 16:02

right on brother! It's a good time ain't it? I've got another version I'm working on right now as well. It's got another Ge stage on the end and some FET buffers. It's going to be the kind of "Cadillac" version with more options and even more gain on tap. Should be fun. I'll post when I get I sorted.

DrNomis · Post by **DrNomis** » 01 Dec 2010, 17:08

And I thought I had seen all the really cool stompbox projects that freestompboxes.org had to offer,how wrong I was...

RnFR · Post by **RnFR** » 27 Mar 2011, 15:12

here's my latest Green Bomb-
http://apocalypseaudio.blogspot.com/201 ... uzz-1.html

i did a bit of tuning by ear, and added an input buffer, because it's for a guy that mainly plays fingerstyle, and i found that it helps kick the signal along and even things out a bit when you arent using a pick. i'll make up a schematic if anyone wants one. more on the blog.

bigmufffuzzwizz · Post by **bigmufffuzzwizz** » 27 Mar 2011, 17:45

Got the vero layout! Now i gotta give this one a go!!!

flatcrabs · Post by **flatcrabs** » 28 Mar 2011, 01:26

That looks fantastic. The Green Bomb I built has issues and seeing this makes me want to dig it out for some debugging...

And what kind of enclosure is that? It looks nice and roomy.

Great work, as always.

RnFR · Post by **RnFR** » 28 Mar 2011, 01:51

bigmufffuzzwizz wrote:Got the vero layout! Now i gotta give this one a go!!!

i think IvIark has one on his blog. this one has a FET buffer with a .22 input cap, and a 1K resistor and a .01 cap on the input to stop oscillation, the input caps are .1 and the output caps are .01 to brighten it up a bit. other than that, i think it's the same. i'll take a look at it if you want me to make sure. the 50K audio tone pot gets fuller as you turn it up.
you don't want my layout- i forgot the 10K cap on the buffer, and had to put it trackside.

i never drew it out anyway.

flatcrabs wrote:That looks fantastic. The Green Bomb I built has issues and seeing this makes me want to dig it out for some debugging...

And what kind of enclosure is that? It looks nice and roomy.

Great work, as always.

thanks, man! yeah, it's worth checking it out. the box is a D series from pedalpartsplus. i think it's plum sparkle. looks really cool in person with the dark green knobs and green LED. very incredible hulk!

RnFR · Post by **RnFR** » 28 Mar 2011, 03:35

yeah, that's it. sorry, ibo!

just a mention- with the buffer, it's probably not as versatile, but it does the sixties fuzz sound really well. i'm kind of torn about it. if you are looking for strictly fuzz sounds, try the buffer, it's really cool. just make sure to add a series resistor and cap to gr at the input. i used 1K/.01.

RnFR · Post by **RnFR** » 01 Apr 2011, 03:33

flatcrabs wrote:
And what kind of enclosure is that? It looks nice and roomy.

sorry, i was wrong. it's the 1790 from PPP.

DrNomis · Post by **DrNomis** » 01 Apr 2011, 08:25

I actually had the song "Spirits In The Sky", in my music folder on my computer, and listened to it first, the demo sounded cool, just like the fuzztone that you hear in the song....

neoflox · Post by **neoflox** » 08 Jul 2011, 21:44

Hi there,

first up, thank you very much for the great work on this circuit! Since I really dig the Mosrite circuit, I started breadboarding it to see whatI can get out of it. I also had a look at the modifications of the GB and stumbled upon the 680pF caps on the transistors. I figure they are supposed to filter certain high freqs but I when I replaced them with different values I found that it does not made a difference at all. Even taking it out does not sound different. I didn't include your tone control yet. Would you be so nice to enlighten me upon this detail?

RnFR · Post by **RnFR** » 09 Jul 2011, 02:26

I pretty much explained the technicalities of the tc earlier in the thread, there really isn't much more I can say. if you have any specific questions, it might be easier. the small caps should reduce the highest frequencies and any noise. are you sure they aren't 68pf? some caps are marked 680 are really 68p. 680pfs are
marked 681.
here's the post about the tc. it's really the part of this circuit that sets it apart. I would definitely try it out.

https://www.freestompboxes.org/viewtopic ... 655#p93653

neoflox · Post by **neoflox** » 09 Jul 2011, 10:11

Alright thanks. The post you linked didn't say anything about these capacitors but I guess I will just trust my ears here. And yeah, thanks for the nod but I am able to tell 68 from 680

DrNomis · Post by **DrNomis** » 09 Jul 2011, 10:53

RnFR, I was just wondering if it is at all possible to make a Germanium Transistor version of this Fuzz stompbox?, I'd imagine that I would have to change the values of some of the resistors, yeah I know that Germanium Transistors are more temperamental than Silicon types, I'm mostly interested in doing it just for fun, I've got some spare Ge Transistors with decent gains, and I also happen to have a Semiconductor Component Analyser (a bit like those Peak Atlas things), as far as I know, I can't see why it shouldn't work....

RnFR · Post by **RnFR** » 09 Jul 2011, 13:26

that post was about the tc. if you are not sure about a value use a DMM.

DrNomis · Post by **DrNomis** » 09 Jul 2011, 14:47

RnFR wrote:that post was about the tc. if you are not sure about a value use a DMM.

Cheers, RnFR....

By rights, I should already know that.....

RnFR · Post by **RnFR** » 11 Jul 2011, 00:09

i was responding to the post before yours. i've done it with Ge's before, it works well. if you bias it right, you could use about any type of transistor.

DrNomis · Post by **DrNomis** » 11 Jul 2011, 00:16

RnFR wrote:i was responding to the post before yours. i've done it with Ge's before, it works well. if you bias it right, you could use about any type of transistor.

Yeah, I was thinking that it would be all down to the biasing myself.... cheers anyway....

threestar333 · Post by **threestar333** » 16 Sep 2011, 02:01

RnFR,
I’ll second what others have said, thanks for coming up with this circuit and sharing it. It turned out to be just what I was looking for. I wanted to build a Fuzzrite circuit to get two sounds, a full on buzz saw spaghetti western sound like this

and a compressed “farty” synth tone with more bass like this
http://www.myspace.com/boardwalkers/mus ... e-60062295
I spent some time messing around with the Green Bomb on the bread board and came up with this:

OK, so it’s my first build and I got a bit carried away maybe. I futzed around with most of the components to see what they did. I thought it sounded best with a higher Hfe for Q2 than Q1 (the opposite of what I found with the classic Si Fuzzrite circuit). I could change the overall brightness with Q1’s output cap (C5 in my schematic), but that also effected the function of the fuzz control, apparently the fuzz pot acts to reduce fuzz, the smaller C5 is the less it reduces the fuzz, if C5 is small enough then the fuzz control does nothing. I ended up using .0022uF, along the lines of what you recommended. My final version uses cap switching for the Q2 output cap and the cap to ground in the tone control, by switching both of those I can get both tone extremes that I am going for. I call that the “Ugly Switch”, so I can call the other two controls the “Good” and “Bad”…. Geddit….
Any who, once I got this hooked up on the pedal board it turns out it didn’t get on well with the only non-true-bypass pedal I have in the chain, a Monte Allum modded CS3 compressor. It seemed to change the tone whether it was in front of or after the Green Bomb. Also, if the GB came after my BBE wah it would kill the wah, before the wah would give a reduced fuzz and the wah would become a kind of combined wah/volume pedal. Hence the input buffer on the Green Bomb, I tried Aquataur’s circuit, but found the simpler jfet buffer circuit with one less resistor maintained the original tone better. Thanks to Aquataur’s suggestion I included the 50K vr between the buffer and the input cap of the GB. When this is shorted the circuit has slightly higher gain than stock, if you cut it back a little it regains the original “farty” synth compression, in fact there’s a slight volume swell as mentioned by someone else on this thread. If you turn the vr down further you can lower the gain further for less sustain and more knob twiddling goodness. As you suggested I added an RC low pass filter at the input of the buffer which stopped the oscillation I was getting when unplugged or with certain pickups (so how does that work? Is it radio interference that starts the oscillation in the first place?). The input buffer seems to keep the tone of the GB the same where ever it is in the chain, but it didn’t change anything as far as the wah is concerned. I added the output buffer ‘cos I thought the tone of the circuit was being altered by pedals downstream, but on further testing I’m not so sure it’s really necessary, I might cut it to save space.
So, that’ s my build report, with the pickups and amp I’ve been using it get’s the sounds I want, see any glaring errors before I stick it in a box?
Cheers,
***

RnFR · Post by **RnFR** » 16 Sep 2011, 03:54

looks cool! the only thing i would do on first glance, is add a coupling cap before the output buffer. as of right now, you've got some DC on the pot. how much, of course depends on how big those biasing resistors are. if they are huge, it might not crackle, but it's just good practice. you could also think about doing the switching after the buffer if you want true bypass, but that is just personal preference. i like the ugly switch! great idea.

here is a pic of a modified GB that i did with a buffer on the front.

http://apocalypseaudio.blogspot.com/201 ... uzz-1.html