Negative voltage regulator

[served]

Hi.

I was just reading a thread one day, and started to think, how to solve that biasing issue in Fuzz Face Germanium, or other pedals with germanium transistors.
I looked through some electronic catalogues and things, but I could not find a way to keep the bias constant.
Has anyone made a breakthrough? Somekind on chip or regulator? It would be a huge step, if you wouldnot have to think about bias anymore.

A.

[GibsonGM]

I'm sure it could be done to some extent with comparators etc., altho many of the device parameters change differentially as the temperature drifts.  So the required bias wouldn't follow a linear path to yield the same results, if that makes sense.   

In the end, it seems like it would be a very complicated undertaking on one hand, but not so hard on the other provided you weren't looking for the performance to remain the same.  I hope R.G. gets into this one, thermal stuff is wild and well beyond the scope of most of us mere humans! 

[served]

Temperature is on tough thing. Cant get through it and over it. But it would be really cool thing to achive.

[slacker]

Have a look at John Hollis's Rock Face http://www.hollis.co.uk/john/circuits.html that's the nearest I think anyone has come to attempting to solve the problem.
There is another fuzz face type ciruit that used a bias pot but added an LED that showed you when it was correctly biased, I can't remember what it's called though.

[slacker]

Here it is http://g.landry.myweb.absamail.co.za/Smileyface.htm

[Nasse]

Found this in wikipedia

"For critical applications the quartz oscillator is mounted in a temperature-controlled container, called a crystal oven, and can also be mounted on shock absorbers to prevent perturbation by external mechanical vibrations."

Such circuit could be made inside a big enough water container with enough thermal inertia to get trough few hours in extreme hot or cold environment. Perhaps Eric Johnson would buy one.

[served]

Actually, First I considered a heatsink for germaniums, but if the room temp changes, then it doesnt work any more.