Hi,
Did you ever heard about the Black Ice overdrive ? It's a StewMac product, claimed to add a bluesy crunch to any passive guitar, by replacing the tone cap by a small black cube-shaped device.
This thing is known to be a simple diode clipper to ground, using low-threshold Schottky diodes for un-amplified signal.
http://www.projectguitar.com/tut/blackice.htm
http://archive.ampage.org/threads/2/gtg ... Ice-1.html
I tried the Schottky clipper on my Epiphone SG, which has quite hot pickups. It seemed a bit harsh to my ears, losing a lot of volume. I went for assymetrical clipping with one Schottky and one silicon 1N4148, and i like it better. It's not really great sounding, but adds versatility. For example you can change the sound of another overdrive, it's a bit more dark and compressed.
The trick i've found, is that you don't need to loose your tone control when using this. I wired the diodes to ground and to the open lug of the 500k tone control, the wiper to the signal line, and the other lug to the tone cap. It's like a cap-to-diodes blend control. I've got normal tone operation from 0 to 7 (removing highs towards 0), and overdrive coming gradually from 7 to 10.
It was even a solder-less operation, as my Epi has the right tone wiring, i just pushed the leads of the diodes into the pot lugs fixations !
Here are some waveforms (screenshots of Audacity, amplitudes not matched), showing assymetrical clipping.
Onboard passive overdrive
- JiM
- Diode Debunker
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Clever!JiM wrote:The trick i've found, is that you don't need to loose your tone control when using this. I wired the diodes to ground and to the open lug of the 500k tone control, the wiper to the signal line, and the other lug to the tone cap. It's like a cap-to-diodes blend control. I've got normal tone operation from 0 to 7 (removing highs towards 0), and overdrive coming gradually from 7 to 10.
- JiM
- Diode Debunker
Information
- Posts: 967
- Joined: 11 Mar 2008, 22:56
- Completed builds: Completed builds :
Proco Rat
MXR MicroAmp in a volume pedal
TubeDriver (w/ NoS russian tube and big muff tone contol) + Phase 45 (w/ univibe cap ratio)
Dallas Rangemaster (w/ noisy OC75, negative ground)
SubCaster tube booster (w/ NoS russian tube, PtP)
Hot Harmonics
Music From Outer Space SubCommander in progress
Crackle Not OK
Simple bass blender in a 1590A
Bazz Fuss with a photo-darlington - Location: France
- Has thanked: 70 times
- Been thanked: 66 times
- Contact:
Thank you ! But it's mainly lazyness ... I didn't want to mess with unsoldering in my guitar just to try this, swap several diodes combinations, and maybe get stock wiring back. So i hooked the diodes on the available pot lug and ground, eventually turned the tone pot during first tests ... "hey, it's cool, let's keep it !"
I equipped the bridge PU only, for use on neck PU one can select both PU and cut the volume of the bridge PU.
It's so simple, anyone should give it a try
I equipped the bridge PU only, for use on neck PU one can select both PU and cut the volume of the bridge PU.
It's so simple, anyone should give it a try
I only give negative feedback.