draw a picture for an idiot - adding expression to a delay

[kingnimrod]

hey there,

I am still sort of a newbie as far as modding pedals - I have a bunch of unfinished builds sitting on my desk here.

I have searched the board trying to figure out how to add a couple of expression jacks to an old Tokai delay - When plugged in, I want the expression pedals to control the delay time and feedback.

I have seen something about "switched stereo" but it eludes me as to how to actually wire it. I want to be able to use a standard expression pedal like the roland.

Could someone please show me or draw out a diagram that shows how to  add a jack that will bypass the pot and control the delay/feedback?

thanks,

your pal dumbass

[Mike Burgundy]

If there's a pot that controls delay, and it's wired as a rheostat (variable resistor - two lugs essentially are used) you can stick in  a stereo switching jack in series. One of those that shorts out the ip to ring when nothing's in but opens that up when a jack is inserted. You cabn then use a regular volume pedal as expression pedal.
I can draw you a pic, first find out if the pots are rheostats. It's really easy.

[kingnimrod]

here are some pics of the pots

Feedback and level pots




Delay time pot



This one is kind of weird - some sort of protective housing soldered to the bottom - also works in reverse of how most delays do - turning clockwise decreases the delay time. How do I reverse that?

thanks for the help

[kingnimrod]

oh yeah - only two lugs are in use on the delay pot.

I would also like to wire an expression jack for feedback, though - and that is wired on all 3 lugs.

[kingnimrod]

by the way, this pedal started its life as a Tokai TDL-1 delay. Some guy gave it to me for free - it had some broken solder joints and a bad stomp switch, but that was easy enough to fix. Sounds really nice and quiet - only noise is when the feedback is up high, regens get lofi. Best $0 I've ever spent (not including the repair parts and new Hammond case, metal flake paint job, etc etc), heheh

here's the schematic for this pedal

[Mike Burgundy]

okay, what's the pot value? 1M in the schematic.
Okay, carefully unsolder one (doesn't matter which one) of the wires to the delay pot, at the PCB.
This is where you insert  the expression jack, between that wire and it's pcb pad..
There is a problem though: you'll need to rewire the expression pedal (which is setup like a volume knob) to function as a variable resistor, and stick in a bigger pot. The regular 100k won't give you a lot of sweep. I'd go for 500k.
Use a stereo lead, tip send, ring return.
hih