The Transistor between Amplifier and Oscillator stage in tremolos (ex.Schaller)?

[kimelopidaer]

edit 01/21/12: (link removed)

Would anyone care to explain,
does this transistor 'inject' the oscillators' output into the main signal?
Should I be thinking about it in another way?

I've been putting together simple oscillators on the breadboard and trying to modulate the main signal.
I've had some success having them wobble a jfet boost. I've been connecting the oscillator to the Gate in the boost.
I used a Bipolar junction transistor to interface the osc. with the boost ala the schaller tremolo.

I noticed however, that it creates a tremolo effect,
but the 'bridging' BJT on my breadboard is not connected to a power source.
Is it acting as a switch then? ( emitter to ground, base to oscillator, and collector to the boosts' gate)

ThankYou,
K

[earthtonesaudio]

I think topopiccione does not allow hotlinking, but I assume you are referring to the "new" schematic here.

The transistor Q1 is acting as an electronically-controlled resistance in parallel with R2.  This resistance value, in combination with R1, forms a voltage divider which attenuates the signal before it reaches the Q2 make-up gain stage.
Hope that helps.

[kimelopidaer]

I appreciate that.

So, the oscillators pulse running into Q1 rhythmically opens the junction between collector and emitter and allows the main guitar signal to be briefly shunted to ground through Q1's emitter? And when there is nothing at Q1's base, nothing flows between collector and emitter, and the entire oscillator section of the circuit is 'off limits' to the main signal?

cheers,
K

[earthtonesaudio]

Pretty close.  The audio can not influence the oscillator regardless of whether q1 is off or on.  So the low impedance path to ground is the thing that gets opened or closed, for practical purposes there is no path between audio and oscillator.