MI Audio - Crunch Box

Nicht Bernd · Post by **Nicht Bernd** » 01 Nov 2010, 14:14

Hi. I read in a Tubescreamer-mod the diferent sound of changing the LM833. Is it the same with the crunchbox? Diferent IC´s diferent sounds?

bondan20 · Post by **bondan20** » 17 Feb 2011, 02:01

DimebuGG wrote:here's my own layout with PCB mount pots. Enjoy!...IC is National's LM833..

pliss help me,,this layout verified sir???

bondan20 · Post by **bondan20** » 17 Feb 2011, 02:04

bondan20 wrote:
DimebuGG wrote:here's my own layout with PCB mount pots. Enjoy!...IC is National's LM833..

pliss help me,,this layout verified sir???

https://www.freestompboxes.org/download/file.php?id=1375

dergroovemeister · Post by **dergroovemeister** » 22 Feb 2011, 23:07

Does anyone have a verified stripboard layout for me?
Thanks in advance!

snafuX · Post by **snafuX** » 23 Feb 2011, 07:22

yeah built one of these and very satisfied, but mine is a little closed even with the tone massed , how can i add some highs , is there any mod to increase the highs and to open it up a little?
thanks a lot

rocklander · Post by **rocklander** » 06 Oct 2011, 10:49

so I made a 1590a layout for this.. and built it cos I couldn't find any inconsistencies between the schem and my layout (that doesn't mean there aren't any, I just couldn't find any

).. I don't like it, and winder if anyone can comment on it.
played into my 'ruby' amp.. I get a crisp distortion up to about 75% of the gain, but over that it suddenly goes wooly, and if I let a note ring, it kind of gates between wooly fuzz and crisper distortion.. pretty sure I've done something wrong cos I don't see anyone actually wanting to use the thing I have made.. just too unpredictable..

anyway... here tis..

included is the ripdivot/matsumin schematic.. hope that's okay?

[click here for updated layout]

burchtone · Post by **burchtone** » 06 Oct 2011, 11:47

Looks like you have R2 (the 1M biasing resistor) going from pin 3 to GND. You'll want that to go to Vref instead.

rocklander · Post by **rocklander** » 06 Oct 2011, 19:06

burchtone wrote:Looks like you have R2 (the 1M biasing resistor) going from pin 3 to GND. You'll want that to go to Vref instead.

superb.. I knew it shouldn't sound this bad

thanks for that.. another pair of eyes always helps

burchtone · Post by **burchtone** » 06 Oct 2011, 20:59

no worries!

rocklander · Post by **rocklander** » 08 Oct 2011, 01:50

updated.. and I think I got it right this time.. moving the 1MR to vref improved things greatly

pcb

: mi-crunchbox-pcb2.01(c).jpg (110.92 KiB) Viewed 3378 times

layout

: mi-crunchbox-layout2.01(c).jpg (115.32 KiB) Viewed 3378 times

pdf (A4 sized paper) and expressPCB files

MI Crunch Box.zip: (255.19 KiB) Downloaded 485 times

DrNomis · Post by **DrNomis** » 08 Oct 2011, 02:25

rocklander wrote:updated.. and I think I got it right this time.. moving the 1MR to vref improved things greatly

pcb
mi-crunchbox-pcb2.01(c).jpg
layout
mi-crunchbox-layout2.01(c).jpg
pdf (A4 sized paper) and expressPCB files
MI Crunch Box.zip

That would most likely solve an Op-Amp biasing issue....

mysticwhiskey · Post by **mysticwhiskey** » 08 Oct 2011, 05:05

You sure you had the 1N4001 the right way around? The cathode (banded end) should go to the square pad. Doesn't seem weird to me, plenty of layouts use this method of polarity protection.

Website · Post by **Lonkero** » 10 Oct 2011, 02:16

I built this a year ago. Mine's got a bit of a problem though. When driving this alone to my amp it sounds good, very dynamic. But when I put it on my pedal chain, no matter which position it totally losts it dynamics and sounds like crap. Maybe it's just a picky pedal which doesnt like other true bypass pedals at all. Does anyone else noticed the same?

rocklander · Post by **rocklander** » 17 Oct 2011, 06:12

one of the guys at nzguitars.com opened up his version of this.. loving the 'goop'

Post by **jstbrowsin** » 17 Oct 2011, 07:58

Thats a laugh eh

wait!!! Isn't that the solder side ?

tiagojoy · Post by **tiagojoy** » 27 Nov 2011, 22:35

my crunch box, very good sound!

euronymous0001 · Post by **euronymous0001** » 11 Dec 2011, 06:08

Seljetnoma wrote:Hi,

I modded my crunchbox V2 into tonefreak Severe specs, really simple to do and it made the crunchbox so much more dynamic.
One thing that kept me from using the crunchbox was it's excessive mid honk, but it seems like it's a bit less now with the Severe mod, and it's way more usable.
I kept the crunchbox presence pot instead of the switchable treble boost on the Severe, and last but not least I replaced the 220n cap right after the 1st stage of the opamp with a 1mf cap, I like it better this way, also helps on lessening the mids.

Cheers,
Frank

i wanna know if you also relocated the clipping diodes to the feedbacl loop of ICa or you retained it as it is, after the 2u2 cap to ground. tnx

viggersster · Post by **viggersster** » 04 Feb 2012, 02:12

devastator wrote:hi,

I did a striplayout of crunch box, I share it with you.

NOT VERIFIED !

i'm sure this is a really really stupid question, so i apologize in advance for asking it, but what is the "Vr" wire supposed to connect to?

IvIark · Post by **IvIark** » 04 Feb 2012, 02:22

I doesn't connect to anything. All the connections to Vr have already been made in the layout so he probably did that as a prompt as to where the rail was when he was putting the layout together

viggersster · Post by **viggersster** » 04 Feb 2012, 02:29

thank you very much! i am just getting into building and couldn't figure it out for the life of me.

MI Audio - Crunch Box [traced]