LERA circuit with an Arion SCH-1.. Mark Hammer?

[Neal]

I built a LERA leslie sim circuit, info here:
http://www.geofex.com/Article_Folders/lera/lera.htm

It works great with my old DOD chorus. I'd like to use it with my Arion SCH-1, but I'm not sure if it'll work. I found this schematic for the Arion (thanks, Mark Hammer!)

http://img.photobucket.com/albums/v4...ereoChorus.gif

Before I start modding the Arion, can anyone tell me if I'm barking up the wrong tree here?

Thanks!
Neal

[Mark Hammer]

Yes and no.

The basic 2-opamp LFO circuit has two versions of Rate control that it can use: voltage divider, and rheostat. The LERA assumes the second type (one single variable resistance that can be replaced by a photocell), whereas the SCH-1 uses the second type.

In principle, you could take out the Rate pot, 470k and 5k6 resistors, and replace it with a photocell and some series resistance, However, you would need to do some experimentation to figure out what the values ought to be. Additionally, you may find you need to change the value of the feedback/integrator cap in the second half of IC3.

So, feasible, but not a straightforward drop-in replacement.

[Neal]

Thanks for the reply, Mark. The little Arion sounds so good that I'm hesitant to mod it for fear that I'll screw it up. I do have a TIP third hand pedal that will work, although it's a little unwieldy, to change the speed.
If I find an Arion cheap at a pawn shop or music store, I may give it a shot. I really like the idea of the LERA circuit, and it works fine with my old DOD pedal. I may have to see what it'll do with my EH Electric Mistress.
Thanks again for the info!
Neal