Krank Distortus Maximus DIY and Mods!

This is a Krank Distortus Maximus (DM) diy build with a few tweaks. This high gain pedal made originally by Krank is quite an interesting distortion pedal with minimum parts and an unconventional clipping circuit. The heart of the DM is the classic LM-386 chip (or JRC386). This is a small power amplifier chip designed for portable low-wattage devices. When this chip is overdriven, it sounds pretty much like an overdriven power amplifier and this is a good thing! Power amp distortion is what guitar players are seeking when they drive their tube amps to 11! The power tubes produce rich harmonics when driven near their limits. The decibels produced can be ear-bleeding though. That's why many low wattage high gain tube amps are being produced nowadays (such as the Blackstar Ht-1 1W tube amp). The DM is NOT a tube pedal but it sounds really good as it's based on the same principle.
Here's a photo of the original DM:

(Source: http://www.musiciansfriend.com/amplifiers-effects/krank-distortus-maximus-distortion-pedal )

And here's the schematic diagram of the stock DM:

(Source: http://www.diystompboxes.com/smfforum/index.php?topic=111870.0 )

Here's the board layout of the DM, suitable for DIY builds:

(Source: http://tagboardeffects.blogspot.gr/2011/01/krank-distortus-maximus.html )


Here's a couple of photos of my DIY DM that was built by a friend:

MODS!

Here's the modified schematic diagram for the DM:

Here are the mods: 
I replaced the 56kOhm resistor just before the gain pot with a 220ohm one for extra gain.
Also, the 4.7nF capacitor at the input pin 3 of the LM386 chip was completely removed for a bright boost effect.

This pedal does not produce loads of low end like other metal distortion pedals do but I like it this way. It's more versatile and more "focused". It suits low tuned guitars and metal riffs but the lead/solo action is also pretty good with these extra modifications.
It's certainly a fun DIY pedal project for high gain tones!

More Bass, more level, less components:
If you need more bass, just a tone pot instead on an EQ and more output level, here'a modified DM schematic diagram:

Cheers,
Thanos