Bias of Q1 in FF builds

[mojah63]

I know biasing Q2 is talked about a lot but there seems to be scant information on biasing Q1. I've seen Germ FF that have trimmers on Q1 + Q2's collectors but haven't found out why. George Tripps and Dunlop wouldn't put one in a Joe Bonamassa fuzz for no reason. I've heard that there are typical Q1 voltages for silicon and germ ff but nothing definitive. Any takers on this here on this?

[Scruffie]

Biasing Q2 effectively biases Q1 up to a working level any way so it's generally not seen as that necessary, not sure what the 'perfect' voltage would be but the two would interact so there'd be some playing but i'm sure it might help fine tune certain transistors.

[mojah63]

Yeah I know it's not necessary for it to work. But there must be some mojo there... Just wondering what it could be.

[jkokura]

No mojo. Just electronics.

Jacob

[mojah63]

Ok, why the trimmer on q1 then?  It's not a booteaker builder doing this.  They must be adjusting for something in production. A fixed resistor is a lot cheaper.

[JakeFuzz]

I've done it before. My voltages typically are around 0.5-1.5 volts on Q1C. There is a pretty wide range that doesn't change the sound much but closer to extreme values you start to get more "boominess" in the sound. I would try it out. It is a pretty worthy, simple experiment, its been a while since I've messed with that resistor. I usually leave it at 33K and get very good results over the wide range of Ge's I have tested. I do remember tweaking around with it for some of the Russian transistors I've used. I think the feedback (100K) resistor is probably a more common value to tweak with, huge variations in sound when you change it.

[mojah63]

THANKS a lot     I did a lot of searches here, diystompb, and FSB. Saw a thread on diy but nobody could say in laymans terms what is going  on. I do have a AS in EE and know my math but there is more to music than just math alone. Haberdasher told me you were the man for this.... thanks again jakefuzz