Crunch IT ! - My small contribution.

[Samy]

I found one schem floating around and to improve my poor pcb drawing skills, decided to give it a try.
I think you can guess that this is a clone of a very well known pedal, i renamed it because i don't want to have any troubles with them...
To draw the schem. i used the Express SCH program and to draw the pcb used PCB Wizard 3.
I want to have some feedback to track some mistakes and to improve my pcb. Some mods to the actual schem is also welcome, I'm not talking about adding a switch on the clipping, that one it's quite obvious ...
The schem and pcb are not tested, this is only a prototype...
Here are the files:
Download Crunch_IT.pdf

[Samy]

Found one error on the Schematics, only the tone pot was modified.
Here is the update.
Download Crunch_IT.pdf

Sorry for the mistake...

[Tuemmueh]

Great work, Samy! Hard to guess what it's based on

Would be great if you'd post the pcb-layout, too!

[anti-idiot]

looks great (but i really dont know what it's based on -send me a PM )

[Samy]

Thanks for your kind words.
I will post the pcb file after checking everything, i want to be 100% shure that the pcb is correct.

[mattpocket]

looks great (but i really dont know what it's based on -send me a PM )

same here... im relatively new... but I do love a good clone

[Meanderthal]

 Looks like tubescreamer meets distortion+... or more like a ratlike thing... can't quite place it either...  Familiar though...

What's up with that tone control? Am I missing something?

[bean]

The op-amp clued me in (in the schem). Oh, and the name 

Anyway, I think I'll breadboard this one just for fun. Thanks!

[snoof]

Looks like tubescreamer meets distortion+... or more like a ratlike thing... can't quite place it either...  Familiar though...

What's up with that tone control? Am I missing something?

Looks like it's altering the R of the RC filter??

[j.y]

thk u so much..  its a clone of a excellent pedal..

[Meanderthal]

 

Looks like it's altering the R of the RC filter??

If so, it's a slightly different lowpass method than what I'm used to seeing. But, I'm no expert...

Hmmm... maybe(or maybe not) it affects the fixed rolloff of c8 and to a lesser degree c9...   I've never noticed one like that before...    'S why I was wondering if there's something I'm missing... not quite yer standard lowpass tacked on the end... but close.

BTW, excellent looking work Samy, whatever it is...(still don't know, too dense to catch the clues)

[markm]

BTW, excellent looking work Samy, whatever it is...(still don't know, too dense to catch the clues)

What clues??
I don't think I know either! 

[Shepherd]

http://reviews.harmony-central.com/reviews/Effects/product/MI%20Audio/Crunch%20Box/10/1

[jonathan perez]

 

(im telling!)

just kidding.




who the heck would i tell, anyways?

[Meanderthal]

 I'm getting old... never heard of it... but it sure gets good reviews! 

[Phorhas]

Wierd... MI says that it has 3 gain stages (or was it 3 clipping stage?)

[Phorhas]

I guess that 2 LEDs make a "stage" these days 

[km-r]

sound clips??

the reviews look good.

[bean]

I breadboarded it this morning and it worked. Only thing I had to fiddle with was reversing the outside lugs of the drive control (you might want to double check it--also minimum drive setting kills the signal, I think).

I made a couple of subs, namely 50pf for 100pf and not having an LM833 or TL072 I used the crusty old 4559P. I also used a 100kB for the drive instead of an audio taper (you have your tapers listed as B & C in the schem?). I'm curious what other values might work in the drive control (it has a lot of gain as is, however).

Anyway, from what I remember it sounds close to the original. But, I also was playing at minimum volume through my ruby amp while testing it out (trying not to wake the kid here at 5am) 

Thanks Samy!

[brett]

Hi
Is anyone else confused by the strange biasing?  Pin 3 (the non-inverting input) seems to connect to 9V via a 1M resistor (R2).
Pin 5 (stage 2 non-inverting input) has a normal, if non-centred bias (ie 10k and 22k resistors to supply and ground, repsectively).
cheers