Monday, May 3, 2021

BALMORAL ELECTRIC: Kool Thing Distortion

This is an LM386L based distortion that I've been playing with - I called it Kool Thing as I was testing it on one of my guitars that has an open tuning (DADDAD for the record), and I was getting a distinct Sonic Youth vibe - which is not all that surprising with that tuning. 

It's basically a variation of a Spaceman booster up front, and the LM386L section is based on the data sheet, with some inspiration from the D*A*M Sonic Titan.  I did add a gain control to the 386 and have set this circuit up so it can run from clean to quite a lot of distortion, which is pretty cool.

I also tried the Q3 section of a MKIII style circuit after the amp to give it a bit more flavour - it was interesting but not worth the trouble.

It’s debatable that it actually needs two drive/gain related knobs, but I like the flavours you can get by combining the two.  If I had the drop one, I’d remove the gain control and just set the LM386L to full (cap jumpering pin 1 and 8).

I kept the value of the cap used in the tone control quite low to, as I don’t like tone controls that cut really heavily.  Even with a 2n2 this has plenty of roll-off.

It will sound different / not as good if you use an LM386N, for me, the LM386L is definitely better.


BALMORAL ELECTRIC: KOOL THING LM386L DISTORTION - VERO LAYOUT

BALMORAL ELECTRIC KOOL THING LM386L DISTORTION - VERO LAYOUT



 V2:  correction, had the LND upside down on V1



KOOL THING SCHEMATIC





ON THE SCOPE / FFT

CAUTION:  Start with device volume very low; these are 440hz sine waves that vary in level
 
Boost stage

 
Drive sweep, 0 to 100.  Gain 100
 

Gain sweep, 0 to 100.  Drive 100  

 

Drive sweep, 0 to 100.  Gain 50

Tone sweep, Drive & Gain 100

 

Clean Boost







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