Ok, I've been messing around with pedal mods off and on for a few years. This weekend I took my modded SD-1 pedal and temporarily wired a socket so I can swap in clipping diodes easily.
To give ya the Reader's Digest version, the distortion of the SD1 and most distortion/overdrive pedals is generated by two or three diodes clipping the output. Some pedals use two diodes, some put it in a different place in the circuit, but a LOT of pedals use this. What's interesting is that you can place different types of diodes, including LEDs to get varying qualities of overdrive. Also, some diode types clip sooner, some later... and some fuzz the hell out of the signal, some barely affect it.
One note about these clips: I set the pedal for full volume and overdrive, and tone at noon. I was NOT trying to get the best out of each combination, and some are pretty craptacular. Guitar used was a USA Charvel strat. Each part is a bridge Seymour Duncan Hot Rails humbucker first, then middle and neck combination with dimarzio vintage single coils. No effects after the fact, except for some normalization to make the volumes closer together.
Each clip except for the clean one has the following test riffs:
1) Some Joe Walsh rhythm thing
2) Sweep lick, to check tracking
3) Little wing solo
I recorded several combinations, using an EL84 Twister amp I built. Here's the amp without the pedal:
http://members.cox.net/kristenturley/Clean,nopedal2.mp3
And here's the pedal without any clipping diodes:
http://members.cox.net/kristenturley/SD1nodiodes.mp3
One small red LED, and one small diode:
http://members.cox.net/kristenturley...smalldiode.mp3
One large Diode (14007) and one small diode:
http://members.cox.net/kristenturley...smalldiode.mp3
A pair of large diodes (14007)
http://members.cox.net/kristenturley/21n4007.mp3
A pair of big red flat LEDs
http://members.cox.net/kristenturley...edflatLEDs.mp3
A pair of the small diodes
http://members.cox.net/kristenturley/2smalldiodes.mp3
A pair of small red LEDs
http://members.cox.net/kristenturley/2smallredLEDs.mp3
3 small diodes, or assymetrical distortion
http://members.cox.net/kristenturley/3smalldiodes.mp3
Interesting, eh?
Pete
To give ya the Reader's Digest version, the distortion of the SD1 and most distortion/overdrive pedals is generated by two or three diodes clipping the output. Some pedals use two diodes, some put it in a different place in the circuit, but a LOT of pedals use this. What's interesting is that you can place different types of diodes, including LEDs to get varying qualities of overdrive. Also, some diode types clip sooner, some later... and some fuzz the hell out of the signal, some barely affect it.
One note about these clips: I set the pedal for full volume and overdrive, and tone at noon. I was NOT trying to get the best out of each combination, and some are pretty craptacular. Guitar used was a USA Charvel strat. Each part is a bridge Seymour Duncan Hot Rails humbucker first, then middle and neck combination with dimarzio vintage single coils. No effects after the fact, except for some normalization to make the volumes closer together.
Each clip except for the clean one has the following test riffs:
1) Some Joe Walsh rhythm thing
2) Sweep lick, to check tracking
3) Little wing solo
I recorded several combinations, using an EL84 Twister amp I built. Here's the amp without the pedal:
http://members.cox.net/kristenturley/Clean,nopedal2.mp3
And here's the pedal without any clipping diodes:
http://members.cox.net/kristenturley/SD1nodiodes.mp3
One small red LED, and one small diode:
http://members.cox.net/kristenturley...smalldiode.mp3
One large Diode (14007) and one small diode:
http://members.cox.net/kristenturley...smalldiode.mp3
A pair of large diodes (14007)
http://members.cox.net/kristenturley/21n4007.mp3
A pair of big red flat LEDs
http://members.cox.net/kristenturley...edflatLEDs.mp3
A pair of the small diodes
http://members.cox.net/kristenturley/2smalldiodes.mp3
A pair of small red LEDs
http://members.cox.net/kristenturley/2smallredLEDs.mp3
3 small diodes, or assymetrical distortion
http://members.cox.net/kristenturley/3smalldiodes.mp3
Interesting, eh?
Pete
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