Another dirtbox build, Super Crunchbox

When a friend showed me a Gearmanndude Super Crunchbox Utube demo I was kinda impressed with it, but being a cheap SOB, I didn't want to buy one, not when I can build one for less than a quarter of the price. I got a schematic off the net & a "Crunchbox V2" perfboard layout & got to it, adding the necessary bits to make the super crunchbox. This is the result. (as you can see I haven't labeled it yet & was short two control knobs). Man, this is one loud mofo pedal. Controls are, upper right to left, Gain & Level. Lower right to left, Tone, Hi/Lo gain switch, 3 position Compression (clipping) switch & Presence. The Comp swith selects between LED clippers (two 5mm red LED's, & yes they light up, moreso the harder you push it), no clippers in the middle position or silicon diode (1N4148) clippers. The diode clippers is the only place I deviated from the original circuit. I used 3 diodes for asymmetrical clipping, with the negative half of the waveform being clipped most. Whereas the original MI Audio Crunchbox circuit was 9V powered, the "Super" has an internal charge pump to up the voltage to 18V. As I have two 18V outlets on my pedalboard's supply I left the charge pump out. I haven't had a chance to try it out a high volume yet, but at the moderate volume I tried it on it didn't disappoint. Looking forward to putting it through its paces at a decent volume over the next few days & will get back on. Cheers
Edit; it will function on 9V, albeit with less headroom, clarity, touch response etc, well, allegedly anyway. Cheers

Very nice work Ivan.

Delicious!!
Question about mounting footswitches:
I have been putting the metal locking washer inside and the plastic washer under the nut outside.
Is this right, wrong, better, worse?

Nice clean soldering, just the way it should be!

jtcnj said:

Delicious!!
Question about mounting footswitches:
I have been putting the metal locking washer inside and the plastic washer under the nut outside.
Is this right, wrong, better, worse?

Click to expand...

That sounds right!

Cool build, Ivan. Crunchbox is a great Marshall In A Box. I like how all 3 of the jacks are on the backside of the enclosure.

Thanks for the kind words guys. Jtcnj, yes, that's the way I do it. I usually use the plastic washer too but tried both & on this white enclosure thought the metal one looked better. Sysco, I like the jacks & DC plug on the end, takes up less pedalboard real estate that way. On the Gearmanndude demo he used an SG & a Mojotone Lerst amp, which is a Marshall clone, so I knew it'd work well through my rig. I'll give it a decent workout this afternoon. Cheers

I like that jack orientation.

Ok, after several days trying it out & using last night to play a small country pub (I used for half the night & the other guitarist used for the other half & wants to buy it,) I'll give you my thoughts on it. Sysco's mention of a "Marshall in a box" is spot on. Regardless of how its set it is distinctly Marshall voiced. With a total of 6 gain/clipping options it does plexi, boosted plexi (overdrive in front of), to JCM & 80's modified JCM tones & does them well. I like how the tone & presence controls work together, with the tone up the presence can be rolled back so its not ice picky, or with the tone down the presence can be brought up so its not too dark. Trying it on both 9V & 18V supply (it does make a difference), I prefer the clarity & response on 18V. It seems to be a cleaner distortion, if that makes any sense. The other guitarist though, (using a silver face twin reverb) prefered it on 9V. On the "diode clipping" setting I tried it with 3 diodes (asymmetric), then bridged one diode to give the stock clipping. Even though there is a very noticeable volume drop when switching to this setting (easily taken care of with the level control), I prefer it to the asymmetric arrangement, as did the other guitarist, who used it in that setting. I prefer the "no clipping" setting, as a gain & volume boost when taking leads. All in all its a good pedal, I just have to decide, should I sell it or the Super OCD. Cheers

Looks excellent. I bet it sounds nice.

I remember personally hearing the original MI Audio Crunch Box years ago, and I was impressed. I didn't know there was an updated version called the Super Crunch Box. These are seriously nice. Congrats on your build...

I take it that yours is going to sound like this one that is demoed by the ever entertaining "Gearmanndude"

That is the Gearmanndude demo I was shown, inspiring me to build it & yes, that's what it sounds like. MI Audio have now released a V2 of the super Crunchbox that features a 3 band active eq system & an even lower gain setting. Hasn't been reverse engineered yet. If & when it is, I may be able to add to this by re positioning the switches & adding the two extra pots in the switches current position. If I still have it of course. Cheers
Edit; I should add that it stacks reasonably well, not that I think its needed. Pedals that I tried in front of it are Tube Screamer, Rat, Super OCD & an MXR-109 6 band eq (scooped). Of course, the drive was kept low on dirt pedals in front of it, but it handled them well. Cheers