It feels so good...

[Frank_NH]

...when a circuit fires up for the first time with NO debugging!  



This is a Crunch Box distortion, based on the vero layout from this site.   The 3mm led clippers are glowing red after hitting a power chord at max gain!

I modded the stock circuit to reduce the gain a little by substituting a 680K resistor and a 220 pF cap for the 1M and 100 pf cap in the second gain stage (these values derived from the Marshall Gov'nor).  Even with that mod, there is plenty of gain and volume with this thing!

I also removed the V2 tone controls (hence no trimmer) and added in the modded SWTC from Jack Orman's site, documented here:

Stupidly Wonderful Tone Control 2

(It's the third design in the article).  This is the second time I've used this tone control, and I love it because it can go from a treble cut to a treble boost over a very usable range with a single tone pot.

This one will get boxed pretty quickly, as it works better than I ever expected.  With both humbuckers or single coils, you can get a great classic rock, Marshall tone with the Crunch Box (think AC/DC, Led Zeppelin,...).

(BTW - the dual op amp used in my build is a Signetics NE5532)

[IvIark]

Nice job, it looks really cool.  I've seen people mount those LEDs externally somewhere cool (usually in the eyes of the graphic they used as a decal) which would be a great external effect every time you hit the strings.

[Heath]

Awesome.  I'm totally with you... you're done soldering, got your amp warmed up, you've picked out your guitar for the obligatory power chord test, and now it's time to rock.. and it works!  

Makes me want to take a victory lap.



But I'm out of shape so I just take a victory tour of the bathroom (several hours + several sodas + focusing on pedal building = sudden critical bladder alert), then the kitchen for a fresh drink, pet the cats, and back for more.

I used to enjoy a good smoke outside after a pedal build, but I had to quit that.

[ξεναγος νεκροπολης]

yes....it's so cool when that happens...
but it's so bad when you have to.....

desolder...
desolder....

DISOOOOLDER!!!!!!!!!!!!!!







ahhh heath you're so funny with you pics!
i'm laughing on almost every post of yours!

[Frank_NH]

 "I've seen people mount those LEDs externally somewhere cool (usually in the eyes of the graphic they used as a decal) which would be a great external effect every time you hit the strings. "

You can't see it in the photo, but I used sockets for the leds (so I could try out different diodes), so yes I think I'll mount those externally.  They do look very cool since they respond to the signal strength.  BTW, the leds have a measured forward voltage of 1.6 V, and 3mm vs 5mm didn't make any difference.

Heath - yeah it's rare that any of my builds ever fire up the first time.  A victory lap for sure!

"desolder...
desolder....

DISOOOOLDER!!!!!!!!!!!!!!"

It's funny, but I have that very same model and color desoldering tool from Radio Shack.  The tip is now warped from all the desoldering I've done!

While on that subject, one thing I do now for testing purposes is to NOT solder the control pots to their respective wires on the board, but instead temporarily connect them to the bare wire ends via alligator clips (not elegant but it works).  That way, if/when I box the effect, I don't have to desolder the pots, and the wires themselves can be trimmed to the appropriate lengths depending on how the board is mounted.  I'll plan to take some photos of my boxing process when I finish the Crunch Box.

A final note - some have said that the Crunch Box doesn't do low gain very well, but that's not my experience.  I'm able to get some very usable low gain tones with the gain pot at 9 o'clock.  Maybe the reduction of gain in the second gain stage (described above) was helpful in this regard.