Temp stabilisation Rangemaster less gain

Started by Der Groovemeister, October 07, 2008, 01:20:34 PM

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Der Groovemeister

I built a Rangemaster with added reverse biased ge-diode between the base and emitter of the ge-transistor (OC44) to overcome temperature instability (as explained in the Britface article on the Plate-to-plate site:
http://www.geocities.com/SunsetStrip/Studio/2987/britface.html#tempcomp )
It is said to have no influence on the sound, but the gain seems to be a bit higher when i remove the diode. Is that normal?  ???
And how come?

Thanks in advance!
"What do you mean, dynamics? I'm already playing as loud as i can!"

bioroids

I'll triple check that the diode is in fact reverse biased, and then probably recheck the bias. I don't think it should have an effect on gain, but sometimes its hard to not get a little paranoid about this kind of stuff. The best thing to do, ask someone else to put the diode in and out without you looking, and try if you can identify wheter the diode is in or not. That way you'll know for sure if its affecting the sound somehow.

Hope it helps!

Miguel
Eramos tan pobres!

mac

The RM bias makes it quite stable to temp changes. Mine drift a few from 7v (vcc is 9.6v) when finger heated.

Finger heat yours and check if temp run away justify or not the reverse diode.

mac
mac@mac-pc:~$ sudo apt-get install ECC83 EL84