madbeanpedals::forum

Projects => Build Reports => Topic started by: Aleph Null on September 10, 2021, 10:52:29 PM

Title: Half Pint Overdrive (Runoffgroove with mods)
Post by: Aleph Null on September 10, 2021, 10:52:29 PM
This is my take on the Runoffgroove "Grace" overdrive.

(https://live.staticflickr.com/65535/51444689574_0144a6d819_c.jpg) (https://flic.kr/p/2mnZtUs)

The JFET input buffer of the original is replaced here with a BJT buffer for an input impedance of around 1M ohm (depending on the transistors gain). Bias voltage is taken from pin 7 of the LM386 which saves a couple resistors and a little bit of space. A tilt EQ sits at the end. Unlike a BMP, this offers a mid bump. The switch bypasses the tonestack.

(https://live.staticflickr.com/65535/51443190227_8bc0e0ae4d_c.jpg) (https://flic.kr/p/2mnRNcD)

This has the characteristic crackly decay of every other LM386 overdrive I've heard. I wouldn't want to use this into a clean amp, but it does sound very good pushing a dirty amp or another overdrive. You get that percussive attack and the mid boost in the tone control keeps everything tight.

(https://live.staticflickr.com/65535/51443200047_b0f9bc2444_c.jpg) (https://flic.kr/p/2mnRR7X)
Title: Re: Half Pint Overdrive (Runoffgroove with mods)
Post by: harryklippton on September 11, 2021, 08:32:54 PM
That looks really sleek!
Title: Re: Half Pint Overdrive (Runoffgroove with mods)
Post by: Aleph Null on September 14, 2021, 03:42:34 PM
Quote from: harryklippton on September 11, 2021, 08:32:54 PM
That looks really sleek!

Thanks! I had originally planned to do a graphic, but I found I liked the look of the raw aluminum.
Title: Re: Half Pint Overdrive (Runoffgroove with mods)
Post by: harryklippton on September 14, 2021, 08:13:33 PM
Yeah it's a good look and the grey knobs complement it nicely