Biasing BC109 Transistors?

[Joe Hart]

I am building a FF with two BC109 transistors, and when I biased them, I got Q1 to bias with about 20K resistor, but Q2 needed a 963K resistor!! Could that be possible? All the voltages looked correct. Or is this impossible and I must have done something wrong? Thanks.
-Joe Hart

[Joe Hart]

Anyone? I don't want to solder it all up if I'm doing something drastically wrong.
-Joe Hart

[brian wenz]

Hello Hello Joe-
     First off,  I'd put the 33K on Q1 collector [which schematic are you using??] and a 20K pot [wired as a variable resistor] on Q2 collector and then make sure you've got good, solid solder connections.  Are your trannys good?  Are the pinouts correct?
Brian.

[Johan]

I've buillt more than a few FF's using BC108 and BC109. how do you bias Q1? I've allways used the stock value for Q1 collector resistor 33k and found that the collector resistor for Q2 pretty much always land somewhere between 5k5 and 6k5, so I now just put in 5k6 resistors for Q2 instead of a trimmer when building Si FF's....then Q2 allways seem to land somewhere between 4,5 and 5 volts...maby it will be different when i run out of my old telefunken transistors but for now it works...

Johan

[brian wenz]

Hello Hello--
  Joe???  Were'd ya go??
Brian.

[Joe Hart]

I'll try the 33K on Q1. I've read that people seem to like biasing both transistors to about 4.5V. Maybe I've misunderstood? But I will try building it this way and see what happens.  I'll let you know. Thanks!!
-Joe Hart

[brian wenz]

Hello  Joe--
     Naw, just get the collector of Q2 anywhere around 4.5 to 6 [depending on how your ears want the fuzz to sound like].  Did you double-check all the other stuff, too??  Are the trannys socketed so you can switch them with other ones??  [Again, just to double-check.]
Brian.

[Fret Wire]

Joe, sometimes you have to adjust both the 33k and the 8k2 to get proper bias. Sometimes, depending on the trannys, you'll get Q2 to bias around 4.5v, but then the voltages are out of wack on Q1. So, you adjust the 33k a little to bring Q1 back. Then you go back to Q2 and adjust it again. Usually a couple times back and forth, and both trannys will sit right.

Scroll to the bottom and use these voltages as a basic guide. Your's won't be identical, but should be proportionate.
http://www.generalguitargadgets.com/index.php?option=com_wrapper&wrap=fuzzface_inst

Other times, all you have to do is adjust Q2's collector and everything reads good.

[RDV]

5.6k has always been the magic # for Q2's bias resistor in all my FF type builds(including TBs also).

RDV

[brian wenz]

Hello Hello-
  Yeah, I meant that the 4.5 - 6V reading should be for Q2.  As far as resistor values go, I've used from around 4K - 6K - or- so  for Q2 collector.  On original Tonebender MK I and MK II [germanium}  I've found 'em to be anywhere between 6 - 7v for Q2 collector and they all sounded great.
Brian.

[Joe Hart]

My mistake! I misunderstood and thought that both transistors should be biased to 4.5V, so to get Q1 up there, Q2 was through the roof!! Thanks for all the help!!!!
-Joe Hart

[YouAre]

I only know of stu castledine as a supplier of those tranny's, where'd you get yours?

[Joe Hart]

Mr. Daniels at Small Bear!
-Joe Hart