Guitar siren

[rockgardenlove]

So on the SSguitar wiki I found this schematic:

And it goes with this sound sample:
http://fatboy.ssguitar.com/Samples/SIREN.mp3


So, whats causing the siren effect?  I don't see a pot in the schematic or anything?  All I see is an SPST toggle...?

[RDV]

It's an oscillator using the two transistors. Turn the switch on, the siren ramps up, turn the switch off the siren ramps down. It is not a guitar effect. It's a stand-alone noisemaker,

RDV

[RDV]

I also modified the offending WIKI to state that this is just a simple siren, NOT a guitar effect.

RDV

[Nasse]

Tasty delay added, does add realism

[DDD]

Actually the device is a kind of acoustic feedback sustainer if correctly tuned to the desired frequency (note).

[rockgardenlove]

Oh, so its self oscillating then...cool.