Fitting a tremolo in a Morley Wah Enclosure - Optical circuit content

[Nicofromfrance]

Hi all,

I am about to buy a used Morley Wah Pro Series like this for cheap:



I want to put a Tremolo circuit that is already built (Tremulus Lune clone from Musikding) into it ,after removing of the wah circuit, to adjust the speed of the effect with the treadle of the Morley.
The sweep mechanism of the Morley is an optical LED+LDR circuit, and I'd like to fit it in the tremolo circuit or wire a new one to replace the speed pot of the tremolo.

Do you guys think it is something doable? If so, my skills in electronics are not sufficient to determine where to isolate the optical circuit of the Morley to adapt it to the Tremolo. I know that I need to isolate the LED and LDR of course, but I don't know if I need the caps and resistors wired around. Can someone help me please?

Here is the schematics of the Tremolo:
http://diy.musikding.de/wp-content/uploads/2013/06/tremoloschalt.pdf

and the schematic of the Morley:
http://www.morleypedals.com/pwa.pdf

Thanks !

[drolo]

Salut Nico ;-)

Locating the LDR on the Morley should be fairly simple. Just cut the 2 traces going from each of its legs, solder the 2 wires from the trem's speed pot to them instead. You may need to solder a resistor in parallel to it to limit the resistance to 100k like the original speed pot, or you might be ok with it like that and have a bigger range of speeds.

[Nicofromfrance]

Salut David!

Indeed this sound obvious now, thanks! Now as for the LED which is the second part of the optical circuit, after looking at the schematic am I right if I wire the the positive side of the LED (the LED in the optical circuit, not the status LED) to the +9V with a resistor in series, and the negative side of the LED to the other LED on the 3pdt of the Tremolo ?

[drolo]

If you are as lazy as I am .. :-) just leave the rest of the Morley circuit connected so the LED is already fed with the correct current.

I'm not exactly sure why you want to connect it to the 3pdt. This LED is inside the pedal and only serves the purpose of providing a constant light to the LDR. It is not the status LED.

[Nicofromfrance]

You're right I don't need to disconnect the optical circuit LED when the pedal is off. But on the Morley schematic I can see the negative side of the LED is connected to the spst switch, so I thought I would need to wire it to the 3pdt of the tremolo. So now I think I just need to wire this LED to +9V and ground, whatever ground it is?

Thanks again!

[drolo]

You're right, they connected it to the switch too ;-) probably to save current while the effect is bypassed.

In that case, you can leave the circuit as is. If you use a different switch than the one in the Morley, just transfer the LED connections to your swith.