trimmer pot location for transistor bias in colorsound overdriver?

Started by tss, March 29, 2012, 07:18:48 PM

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tss

I will be referring to resistors in this schematic: http://i410.photobucket.com/albums/pp189/grievousangelphotos/colorsound_od.jpg

According to the (original?) schematic, there are voltages for the 2nd and 3rd transistors. With transistor out of my grab-bin, these values will probably be a little off so they'll need some adjustment. For this I need to swap two resistors with trimmers. If I'm not miserably mistaking, I need to replace the 120K (upper left) resistor to bias TR2 and swap the 150K resistor above TR3. Is this correct?

And another question, what if I have an NPN germanium around and I want to try it out? Simply stick in the circuit and bias it? Any other adjustment are needed?

Gus

You should be able to use a wide range of silicon transistors without a trim because of the way the overdriver is designed.   I have simmed it with 2n2222s and 2n5089s the bias does not change much at all.

Why and where do you want to use a Ge in this circuit?

http://www.diystompboxes.com/smfforum/index.php?topic=93814.0