MI Audio Super Crunch Box  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
Post Reply
User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

Is it really true that this version hasn't been retraced yet?

User avatar
MoonWatcher
Diode Debunker
Information
Posts: 715
Joined: 28 Jul 2008, 12:27
Has thanked: 40 times
Been thanked: 52 times

Post by MoonWatcher »

roseblood11 wrote:Is it really true that this version hasn't been retraced yet?
Retraced - good choice of words! :thumbsup

Not sure a tracing would really be necessary. I'd think that 90% is as the Crunch Box has already been for years.

The presence control has finally been put topside instead of as an internal trimmer - probably has same component values.

3-way toggle - probably LED/none/silicon clipping diodes. It's really more of a personal flavor thing beyond the standard LED-type clipping, so I'm (personally) not really curious as to what the "new" diodes in the third setting actually are.

High and Low gain selections - lots of standard ways to achieve that - probably toggles a different resistor value at IC1B's negative feedback loop. Most of these Guvnor-based pedals seem to use 1M, and the real thing probably isn't that much lower gain with 680k. So, just a guess, but maybe it's even lower at 470k/510k/560k - I guess it was tuned a little bit to be a good alternative to the higher gain setting.

I didn't really hear any different voicing in the video vs. the version 1, so I'd assume that nothing was changed that would cause that. Given the popularity and pretty basic expectations with the Crunch Box (lots of distortion, sound sort of like a Marshall amp), I really couldn't imagine that anything was actually changed. It really just sounds like it has more controls vs. the original 3-knob version.

User avatar
J0K3RX
Degoop Doctor
Information
Posts: 1058
Joined: 29 Jun 2011, 01:25
Location: US Florida
Has thanked: 316 times
Been thanked: 556 times

Post by J0K3RX »

Probably because they want to hide something... :hmmm:

Image

User avatar
moonshiner
Information
Posts: 19
Joined: 04 Apr 2015, 04:30

Post by moonshiner »

I think its funny the guy that copied the marshall guvnor gooped his board . It is a very excellent retake on the Guvnor for sure though

User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

It's not really a copy. It uses opamps and LED's to build a clipping circuit, but the gain structure and the tonestack are different. The Guv'nor wasn't bad, but to put an "amp style" tonestack in front of a real amp with tonestack isn't always a good idea. Often the Crunchbox works better, although it has less controls. So, I would call it an improvemnt or a variation, not a clone

User avatar
michael_ibrahim
Information
Posts: 11
Joined: 12 May 2012, 09:47

Post by michael_ibrahim »

roseblood11 wrote:It's not really a copy. It uses opamps and LED's to build a clipping circuit, but the gain structure and the tonestack are different. The Guv'nor wasn't bad, but to put an "amp style" tonestack in front of a real amp with tonestack isn't always a good idea. Often the Crunchbox works better, although it has less controls. So, I would call it an improvemnt or a variation, not a clone
Thank you!

User avatar
FuzzMonkey
Breadboard Brother
Information
Posts: 124
Joined: 28 Dec 2009, 22:10
Has thanked: 44 times
Been thanked: 27 times

Post by FuzzMonkey »

I found this a while back:

Image

User avatar
roseblood11
Tube Twister
Information
Posts: 1887
Joined: 23 Aug 2008, 14:21
Has thanked: 366 times
Been thanked: 313 times

Post by roseblood11 »

Aion electronics offers a pcb for that

User avatar
michael_ibrahim
Information
Posts: 11
Joined: 12 May 2012, 09:47

Post by michael_ibrahim »

Ah,... You've just solved a mystery for me! I was wondering what the Andy Timmons JHS pedal was. It's this design without the charge pump.

User avatar
ivan H
Breadboard Brother
Information
Posts: 64
Joined: 29 Sep 2012, 05:21
Been thanked: 10 times

Post by ivan H »

I see there's a V2 of the Super Crunchbox out now that adds an active 3 band eq section instead of the tone control & another low gain option, making 3 switchable gain options. Still 3 selectable compression options, though the write up lists one as a "Jose" type clipper. Not sure if that's still the original silicon diode setting or not, Jose Arredondo did many variations on clippers, zeners, silicon diodes or a combination of. Just wondering if anyone has had a peek inside a V2 yet. I just finished boxing up a point to point perfboard super Crunchbox. By repositioning the two switches I could fit a 3 band eq in, most likely. Cheers

User avatar
Rogerio
Information
Posts: 3
Joined: 29 Oct 2017, 16:49

Post by Rogerio »

Hi,

I’m very interested in the hi/lo gain feature. I ‘ve built a crunchbox in a breadboard, and I changed some resistors even capacitors, but the results are’nt convincing. Do you have any clue?

Thx

Roger

User avatar
michael_ibrahim
Information
Posts: 11
Joined: 12 May 2012, 09:47

Post by michael_ibrahim »

I do!

Post Reply