Expression pedal with a Dual Gang Pot.

[kizzer]

Hi Guys

I was looking to add an expression pedal input to control the Frequency pot of a self built Maestro MPF1.

I understand that the normal way to do this is to add a switching jack and run the board connections to that jack then on to the pot, however the Frequency Pot is a Dual Gang (6 tab).

Is there a way of doing this?

[11-90-an]

Hello and welcome to the forum... 

Schematic: http://www.synfo.nl/servicemanuals/Maestro/MAESTRO-PARAMETRIC-FILTER_SERVICE_MANUAL.pdf
(Page 10)

For this, you can probably use 2 ldrs controlled by 1 LED, with the expression pedal controlling the brightness of the LED. The brighter the LED, the lower the resistance.

[GGBB]

You can use a dual expression pedal. Might have to adjust the circuit values depending on the pot values used in the pedal.

[kizzer]

For this, you can probably use 2 ldrs controlled by 1 LED, with the expression pedal controlling the brightness of the LED. The brighter the LED, the lower the resistance.

Sounds interesting I'll look into the LDR option.

You can use a dual expression pedal. Might have to adjust the circuit values depending on the pot values used in the pedal.

Yeah, I was thinking about getting a cheap expression pedal and changing it out for the same pot as the MPF1 (Dual C100K) , but what I couldn't understand is that most expression inputs allow for the control of one 3 lug pot. As this is a 6 lug pot, would I need 2 jacks, one for lugs 1-3, one for lugs 4-6?

[GGBB]

Yeah, I was thinking about getting a cheap expression pedal and changing it out for the same pot as the MPF1 (Dual C100K) , but what I couldn't understand is that most expression inputs allow for the control of one 3 lug pot. As this is a 6 lug pot, would I need 2 jacks, one for lugs 1-3, one for lugs 4-6?

Yes - dual expression pedals typically have two stereo jacks. However, in the MPF-1, there are only three connection points for the two gangs of the pot at R21, R22, and C14 - so if you are building something custom, you could use just one stereo jack.

[kizzer]

[quote author=GGBB link=topic=125401.msg1193980#msg1193980 date=1600745252
Yes - dual expression pedals typically have two stereo jacks. However, in the MPF-1, there are only three connection points for the two gangs of the pot at R21, R22, and C14 - so if you are building something custom, you could use just one stereo jack.
[/quote]

Ha, can't believe I didn't see that when I was looking at the board! Thanks very much!