Quick FTM question

[Phend]

Foxx Tone Machine,
On my recent build I notice that the Sustain control can act to increase the volume.  Before I change any values....question: Does R12 at 220 ohm affect the volume produced with the Sustain control?  Thank you in advance.  Paul

[Derringer]

Nope. That resistor is a limiting resistor so that when you turn the sustain all the way down, there's still a little bit signal coming through.

[Phend]

Thanks for the reply Derringer.  I find that the volume increase is dependent on the position of the FTM volume control and the guitar volume control.  So depending on said other volume controls it doesn't always act to increase the volume.  Not being familiar with this effect I was just curious.

[antonis]

All of them are passive attenuators (humble voltage dividers..)
(ignore indermediate stages..)

Consider them as two divider in series (ideally with no loading effect..)
Guitar Vol full up and Effect Vol in middle posistion is equal to Guitar Vol middle position & Effect Vol full up..

[Derringer]

Thanks for the reply Derringer.  I find that the volume increase is dependent on the position of the FTM volume control and the guitar volume control.  So depending on said other volume controls it doesn't always act to increase the volume.  Not being familiar with this effect I was just curious.

Yup. The "sustain" control in this is circuit is pretty subtle. There's so much distortion happening it just helps you tweak the character of the distortion a bit. Some folks have suggested rewiring the sustain pot as a simple variable resistor, 0 to 50K, in series between the two 10uf caps, in fact, you could ditch one of those caps then. That configuration gives a bit more control over the effect's "character."