Jordan Bosstone Q

[MartyMart]

Just built one for a friend, based on one of the two "newer" versions recently posted
and ref against arons schematic.
All working fine, ton of volume and grunt, but if I remove the Q2 PNP tranny (BC557)
there is zero change !
Works perfectly with or without it ??
So signal gets through the Q2 slot to 22n/diodes and output ....
Q1/Q2 use a common 18k link from 9v + , to either collector (Q1) or emitter (Q2)

Any Ideas , usual mistakes/solder work all checked and A OK !

MM.

[Sir H C]

 In the PNP second stage version, the second transistor is just a buffer to the clipping circuit.  As such it should not do much, but if it is out of the circuit, you can see R5 and R6 (from this schematic http://www.diystompboxes.com/pedals/bosstone.gif ) still gives a voltage divider to the clipper so all should work fine.

[aron]

HAH! That's what happened to me long ago. A transistor fell out and it still worked. COOL!

[aron]

Now I see it in a new light. Well, why don't we just put an NPN there wired as an emitter follower?? Saves having to find a PNP transistor.

[Sir H C]

Mine has an NPN in that second stage.  Sounds much better.

[brett]

Hi

In the PNP second stage version, the second transistor is just a buffer to the clipping circuit. 

Actually, the second Q provides an active load that doubles the gain and lowers the output impedance.
Make sure that you've got it connected correctly - From memory, the emitter is connected to the middle of a voltage divider on the collector of Q1 (either 18k:18k or 22k:22k, depending on the version).
It is true that the low output impedance might not be noticed if you've used the 100k output pot and following stages have high input impedance.  But if you've used the 10k output pot, or want to drive something with low input Z, you'll need Q2.
cheers

[MartyMart]

Thanks guy's , I get a tonal change when using a Ge PnP but otherwise can detect
no change !
I'll leave the 557 in there fir now.

MM.