Tube overdrive n tone

[Brian]

A few people new in the advanced chat section already know I bought a Black Ice from Stew Mac and slowly carved it down to see whats inside.

Well the verdict is in and I'll be doing a tutorial soon on how you can have the rich overdriven tone of a tube amp in your guitar for under $3 if you already have the proper pot (requires you to switch to a 250k for your tone pot).

The big mystery was a pair of switching diodes soldered together so that no matter which end is connected to the pot and the ground the signal has a clear path to travel. This doesn't give you a overdrive in volume, what it does is simply shape the tone you already have to simulate a tube overdrive tone signal coming from your guitar to your amp when you turn it up to 10

[PaulNeeds]

those things do work then?

[Brian]

It takes the right combination of pickup DC Resistence and of course this special little trick but yes it works!

[krazyderek]

if dc resistance of the pickup matters then i would recommend some kind of a table for pickups(it can range from 5-30k), pots and the actual black ice make up to get the optimum sound it's supposed to get.

[lovekraft]

Is this the setup you've got in that thing ?

If it's similar to this, it's a simple clipper that chops the peaks off your signal - the pot is unimportant to the clipping, just allows you to regulate the level where the clipping starts. With no pot (or a wide-open setting), the diodes slowly start draining off current to ground as the voltage rises. Silicon signal diodes clip at about 600mV, germaniums at about 300, so this effect will be a lot more obvious with really hot pickups. If you need to know more about how it works, do a search on diode DC transfer function or fuzzbox. Basically, it's a Muff Fuzz with lowered gain. You could even use a larger value for R1 - 2 megs should have little or no audible effect on the output highs regardless of setting. Diodes and pots are cheap, and folks with active pickups or preamps could get some seriously harsh distortion at high settings if you play around with the settings. This is the basic principal behind those '60s cheap fuzzboxes.

Hope that helps - gotta go get my soldering iron!!