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View Full Version : Modded my Crunch Box - moved internal presence control to the outside of the pedal


Deaj
09-19-2006, 11:41 PM
Viola!
http://home.centurytel.net/flanneldrawers/crunchbox_mod.JPG

I like the entire sweep of the presence trim pot and find it easily as useful as the tone control. Now it is a tone control! :)

imcorn
09-19-2006, 11:50 PM
nice! care to post what stuff used for the mod and the schem?

Deaj
09-20-2006, 12:41 AM
nice! care to post what stuff used for the mod and the schem?

It was a simple mod really - no schematic needed. There is a small trim pot on the circuit board. It is a 20k linear taper trimmer. I ordered a 16mm Alpha 20k linear taper pot (part number 313-1000F-20K (http://www.mouser.com/search/refine.aspx?Ntt=313-1000F-20K)) from Mouser Electric, removed the trimmer pot, and wired the new pot to the circuit board in it's place. (the arrow indicates where the trimmer pot was located). The sweeper (center lug) of the trimmer is easy to identify (it's the one closest to the top edge of the circuit board). Be sure to connect the center lug of the new pot where the center lug of the trimmer was connected. The other two terminals have no polarity (you can wire it to have the pot increase presence in either clockwise or counter-clockwise direction). Here's a pic (posted with Michael's OK):
http://home.centurytel.net/flanneldrawers/Crunchbox_mod_inside_arrow.JPG

Hope this helps! :)

Deaj
09-20-2006, 01:47 PM
Have any other Crunch Box owners found the presence control useful?

Jarick
09-20-2006, 02:40 PM
Interesting...so it's an op-amp based pedal using red LED's for clipping...good to know.

I'd be curious to know if they're in the feedback loop or afterwards going to ground.

Thanks for the guts pick! :dude

gkelm
09-20-2006, 02:43 PM
Cool, way cool. :)

scottywompas
09-20-2006, 02:47 PM
Looks to me like LED's to ground. :dude

Jarick
09-20-2006, 02:53 PM
Looks to me like LED's to ground. :dude

Hmmmmm....reminiscient of a Guv'nor. No wonder it sounds "Marshally."

Anyone tried yellow LED's in there?

http://www.mif.pg.gda.pl/homepages/tom/files/guvnor.gif

Deaj
09-21-2006, 05:46 PM
Hmmmmm....reminiscient of a Guv'nor. No wonder it sounds "Marshally."

Anyone tried yellow LED's in there?

http://www.mif.pg.gda.pl/homepages/tom/files/guvnor.gif

What change might be expected with yellow LED's?

Thanks for the Guv'nor schem! :)

jlagrassa
11-09-2006, 05:19 PM
What ever you do dont use green LED's it will turn your CB into a Tube Screamer :D

Just kidding, I just got my Crunch Box V2 and so far I really like it. Definitely better than the Govnor plus pedal I was using but I still like that too! I think Michael did a great job updating the circuit from Ver 1 which I also had you have a lot better control over the pedal!

Moat
11-09-2006, 06:10 PM
I'm wondering if this could reasonably be done to a V1 Crunchbox (without the presence control)? Mine could use a little more "cut" in it's voice.

Occam
11-09-2006, 06:12 PM
I've never touched the presence control in mine and it's at our studio....how much difference does it make and in what way?

Highway Jones
08-23-2007, 06:24 PM
I've never touched the presence control in mine and it's at our studio....how much difference does it make and in what way?

It definitely can sweeten the tone if you have an amp that lacks top end. It also makes it more chimey with single coils IMO. Stock, the trimmer is at 12:00. I moved mine to about 9-10:00.

Highway Jones
08-23-2007, 06:27 PM
I'm wondering if this could reasonably be done to a V1 Crunchbox (without the presence control)? Mine could use a little more "cut" in it's voice.

...probably so...... The stock value I would guess is 10k but, you would need to know the layout or be able to trace the circuit in case there are multiple 10k resistors (I suspect there are).