EH Talking Pedal, possible pot?

[artifus]

not a dual pot but a vaguely related cool idea i stumbled upon recently for antiwah/bi-filter/gargletron/mouthmeister type builds -  if you have a volume pedal, just throw in a stereo jack:



from: http://www.strymon.net/tag/expression-pedal/

[pinkjimiphoton]

nice one art...i used to do that with my ernie ball pedals.

used to make CV pedals doing something similar...plug a cord in the output of the volume pedal to the expression pedal in, and make a plug wired to a 9v snap and plug it in the vol pedal input..

was close enough for rocknroll for a control voltage pedal (before i figured out the trick you did)

[B Tremblay]

Last night I removed the PCB from my PWA and the optical card as well. I didn't realize the card was so bleedin' small!  I will most likely scan in the stock card, then resize Ian's Talking Pedal card template so I have something that is easily printed.  I'll share my results here.

When I was still thinking about using a different controller, I briefly considered using my GuitarRig foot controller. I opened it up and saw that the light-blocking device was a piece of transparent plastic that had some black paint gradually applied over its length.  I began thinking about something similar for the Talking Pedal, using something that could be printed on clear decal stock and affixed to thin transparent plastic. Such an approach could possibly eliminate the need for fussy razor blade cuts.

[Ronan]

Hi Brian, I think the best advice on cutting the card is from Dino on page 3 of this thread:

The only real bitch was to make the card, which harkened me back to my scale model making days. It took me four tries, but I figured out a decent way to mark the card before cutting. I used the cover from a spiral bound note book, which was made of black flexible plastic. On the last go, I decided to fore go the template for the slots, and using the spots created by the light of the LED's, marked the heel, toe, and center positions in the plastic with a pin. I then cut straight slots with an Exacto, following the pin prick points. This is a cue I took from the Morley card, they didn't use any tapering on their slot. Just the fact that the larger cut is approaching the LDR suffices to ramp down the resistance.

I think the easiest way is to cut the card from scratch, like Dino says above, this is how I've done mine all of mine too. (I marked the LED positions on the blank card with fine tip felt pen.) But who knows, there's probably many ways of doing it. It is surprising how much leeway there is to still get a good result. Remember if you make the window or any part of the window too big, you can make it smaller again with patches of masking tape, works fine.

Another point that may help is, the reason I made the legs of the LDR's and LED's to be so long, is to allow relative adjustment between the two filters, since once the card is cut, the relationship between the two filters is fixed, unless you can move one or the other LED/LDR pair closer to or further away from the other LED/LDR pair. Hope that makes sense.

[digi2t]

Another point that may help is, the reason I made the legs of the LDR's and LED's to be so long, is to allow relative adjustment between the two filters, since once the card is cut, the relationship between the two filters is fixed, unless you can move one or the other LED/LDR pair closer to or further away from the other LED/LDR pair. Hope that makes sense.

This was headup thinking early in the game Ian, and a saving grace as well. The fact that I could move the LED's or LDR's a bit, really helped with the final fine tuning. When everything was set, I placed a small dab of 5 minute epoxy between the board and the LED's/LDR's to secure them. And yes, there is quite a bit of leeway insofar as the card slots are concerned in getting decent results. Kind of like horseshoes, and hand grenades  .

[Ronan]

Horseshoes and hand grenades    I got a good chuckle out of that    yep close enough is good enough in this case, I haven't been able to get 2 builds to sound the same either    but I like both of them.

[B Tremblay]

Thanks, Ian, for the tips.  I was worried that the slots needed to be very precise.

I still would be interested in trying to print a decal that is applied to a piece of clear plastic (likely from some obnoxious clamshell packaging).

[B Tremblay]

My progress has slowed to the point that elderly snails smirk at my pace, but I have mounted the PCB in the gutted Morley. I still need to make the card and wire up the offboard components. I socketed the LEDs and LDRs to afford plenty of flexibility.  I was derailed a bit by a lifted pad on the board, but was able to repair it well enough.

[digi2t]

My progress has slowed to the point that elderly snails smirk at my pace, but I have mounted the PCB in the gutted Morley. I still need to make the card and wire up the offboard components. I socketed the LEDs and LDRs to afford plenty of flexibility.  I was derailed a bit by a lifted pad on the board, but was able to repair it well enough.

Keep us posted, and don't be shy if you need any help/info. We're here for you buddy! 

BTW, are you in Quebec?

[B Tremblay]

Thanks for the support!  I'm very enthusiastic, but "real life" keeps beckoning me away from the workbench.  I have this Friday off and hope to whip it into shape then.

I'm in Western NY state.  Both sides of my family have roots in Canada, though (Quebec and Nova Scotia).

[Vince_b]

digi2t, are you in Quebec? I live in Laval.

After reading this thread, the one about the Foxx Guitar Synth Wah, the one about the talk-a-lizer, and looking at your Youtube account, I've come to the conclusion that you knows a lot about expression pedals!
I want to build one but I don't know where to start. I know that this is totally subjective, but which one do you consider the most interesting?

[digi2t]

digi2t, are you in Quebec? I live in Laval.

After reading this thread, the one about the Foxx Guitar Synth Wah, the one about the talk-a-lizer, and looking at your Youtube account, I've come to the conclusion that you knows a lot about expression pedals!
I want to build one but I don't know where to start. I know that this is totally subjective, but which one do you consider the most interesting?

Hey Vince, greetings from Rigaud!
Truthfully, what I know about pedals is a tiny drop in the ocean of knowledge available here in this forum. None of the projects I've undertaken would have come to light if it wasn't for the information that some mighty fine people here have afforded me.

Now, if you're talking strictly between the Foxx, and the Talk-a-lizer, the Foxx is a monster compared to the Talk-a-lizer. Tons of off-board wiring to content with. Not counting the search for a suitable case, the Foxx took me a solid month to redraw, plan, test, modifiy, and build, which was fine, considering I'm on vacation for a good chunk of the winter. For best "bang for the buck", the Foxx wins. Although the Talk-a-lizer is fun, it's a bit limited compared to what the Foxx can produce. Also, he Foxx gave me the opportunity to roll my own custom vactrol, adding to my experience  .

On the other hand, I've enjoyed every build I've done to date. All different, all with their own learning curve. Never a dull moment. All I can say is, depending on your confidence/skill/depth of pocket level, the sky's the limit. Do your research, amass the most info possible, form a battle plan, and go for it. Just remember to ask LOTS of questions. After all, my credo is "There's no such thing as a stupid question, only stupid answers" 

Cheers,
Dino

[Vince_b]

Thanks for all the informations.
I will probably build the Talk-a-lizer first. I really like how it sound and it's gonna be easier since I never build and expression pedal before. But my ultimate goal will be to eventually build the Foxx.

[B Tremblay]

My Talking Pedal clone is finally complete.  Thanks again to Ian and Dino for their work.  I spent a fair amount of time fussing over the card and may continue to do so, but the sound is quite good to my ears.  I hope to record a clip at some point and will scan in my card for reference.

[B Tremblay]

Two clips, clean and dirty.  Not quite as much vowel movement (hey, that's a good name) as I'd like, but I used grab bag LEDs and LDRs as well as 1n5 in place of the 1n8 caps.

http://runoffgroove.com/tp-clean.mp3

http://runoffgroove.com/tp-dirty.mp3

[Ronan]

Sounds great Brian! Nice playing too. Thanks for posting that, sounds good to me, put a smile on my face The clean sound is very nice and clean, nice recording setup/guitar you are using.

If you are tempted to modify the card, it might be worth considering keeping your current card as a "reference" and cut a new one instead, so you don't "lose" what you already have.
Another test you can do is measure the resistance from TP1 to ground and TP2 to ground at different pedal positions, (toe down, middle and heel down), to see if the LDR's are roughly following what the original pots were doing. You don't need any signal going in to do this test, just lay it on its back and rock it and measure.

In an earlier post you mentioned losing a pad on the PCB. Do you think I should get future PCB's made at a different place? I haven't had to replace any components so far, so I have no idea of the quality of the board in that regard. I do know cheap boards will lose pads fairly easily. I'm expecting a small number of different PCB's in a couple of weeks, (from the same place), I'll put one of them through multiple component replacements and see how it holds up.

[B Tremblay]

Thanks, Ian.  I used the same setup (homemade guitar with Tele bridge pup into close-miked Ampeg Rocket II) as when I record 'Groove clips.

I did measure the resistances with the test points (very handy, those) and they are reasonably close to the ones posted earlier.  I think the F2 slot is a little bit more forgiving to cut since it simply ramps up.

Here's what happened with the lifted pad: I had soldered in a jumper for the LED switch and when I removed it, I was not careful enough.  The through-plating makes it difficult for the braid to wick out all the solder.  My iron was probably a little too hot as well.  Later when I had to desolder another connection, I used flux in conjunction with the braid with terrific results.

Can I please reserve a PCB from the new batch?

[digi2t]

Sounds really really good Brian. Good job. The test points are another example of wonderful heads-up thinking on Ian's part. I actually soldered in two leads, that I could feed out through the battery cover. That way, I could check my readings with the cover on, not having to turn off all the lights each time. I then put some heatshrink over the ends, and tucked them into the casing when I was done.

If you're totally satisfied with it, I recommend putting a small dab of 5 minute epoxy between the LED's, LDR's, and the board. That should pretty much ensure that nothing moves out of place if the unit gets tossled about. Not too much that it'll be a pain to take apart, just a dab should do.

Once again, great job! 

P.S. Love the sound of the Ampeg. I recently repaired my G-212, and have fallen in love with it all over again. It's nice to be heard... across town  .

[pinkjimiphoton]

Two clips, clean and dirty.  Not quite as much vowel movement (hey, that's a good name) as I'd like, but I used grab bag LEDs and LDRs as well as 1n5 in place of the 1n8 caps.

http://runoffgroove.com/tp-clean.mp3

http://runoffgroove.com/tp-dirty.mp3

vowel movement....that IS a great name...lol

sounds great...i love the clean clip, very phasey...sounds kinda like this show on tv called "CHiPs" from back in the day. very groovy!! (the clip, not the show)

the dirty clip tho...made me smile.

i've got a morley pwa now to mount it in, (gonna sell the functional guts on ebay i guess) and ian was awesome and sent me the pcb...

so i guess i gotta get some parts and populate. i sold a projector i had kickin' around to my old keyboard player,
so hopefully can finance a mondo parts order from mouser...

then i get to work on this and the pII

awesome job guys. awesome.

i wonder what it'd sound like with an lfo or a sequencer controlling the filter?

[B Tremblay]

Thanks for all the kind words! Tomorrow I hope to take photos and scan the card.  I can also post the resistance measurements from TP1 & TP2. I may solder leads to them, which would be easier than putting the bottom plate over the circuit and hoping that blocks enough light!