Electrovibe

Gordo

Well-known member
Bi-color would be slick. Let me know how the R4 mod works for you. I'd be concerned with clipping but then again that might add some cool character too. Looking forward to seeing what you do.
 

Big Monk

Well-known member
Bi-color would be slick. Let me know how the R4 mod works for you. I'd be concerned with clipping but then again that might add some cool character too. Looking forward to seeing what you do.

R.G. discusses this mod in “Technology of the UniVibe”. The Uni-Vibe Preamp section has about 12 dB of gain on tap. He recommends upwards of 2.2 Meg of resistance at R4, which essentially allows 100% of the inout signal to go through.

Well, the values I listed were just common resistors. For instance, if R4 = 47k (stock) lets 68% of the input signal through, and R4= 100k lets 82% through, we have other common values to entertain there in the middle. I guess we’d have to know the effect of going from 68% signal to 100% on the rest of the circuit.

In my mind, allowing more signal through simple makes it so I have more range on the volume knob, but that may not be a 1:1 correlation. Ideally, what might be best is to take a spare 1590BB baseplate, notch it, and fly leads tacked onto the R4 pads outside the chassis to a 100k-1M pot. Then you could tweak that pot and the volume control and test if clipping becomes an issue.

As for the Bi-color LEDs, they are common cathode so I’d have to switch the anodes and I’m unsure if that would cause any noise issues. I have to look into it a little more. I’d love to do it though.

EDIT: I found common anode bi-color LEDs so I’ll simply tap directly to the 3rd pole of the Speed switch with a Cathode on each side and tap into the the power from the board anode tap.
 
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Big Monk

Well-known member
I think what I'll do on this one is connect the common anode and either the blue or red LED to the pads on the board:

EV LED.PNG

Then it's simply a matter of find the spare terminal on the speed switch and connecting the other LED cathode there with a separate wire. I'll find it prior to soldering the switch in and run it underneath everything to hide it.
 

PedalPCB

Admin (Robert)
Staff member
The design originally had a 2-color LED but there was no obvious indication of which color corresponded to which Speed control, so it was scrapped.

It'll be a little tricky to use the Speed breakout board. The lug you'll need to use is tied to another one, but it'd be fairly easy to wire it up without the breakout board.
 

Big Monk

Well-known member
The design originally had a 2-color LED but there was no obvious indication of which color corresponded to which Speed control, so it was scrapped.

It'll be a little tricky to use the Speed breakout board. The lug you'll need to use is tied to another one, but it'd be fairly easy to wire it up without the breakout board.

Understood. Just out of curiosity, what was the trouble with how the indication worked out? Wouldn't you just assume a color for each speed control, i.e. Speed 1 = Red and Speed 2 = Blue?

Do you have a rough layout of the connections on the Speed breakout board? I like the idea of the breakout boards for general cleanliness so I don't want to scrap that idea at all. Obviously if the spare middle lug is not available you are 100% right and i'd have to scrap the idea if i want to keep the board AND do the Bi-color LED.

Dang!
 

Big Monk

Well-known member
So, armed with the above comments from @PedalPCB, my multimeter and the Speed breakout board, I did a little research and continuity checking.

The center switch on the Speed board has the top most lugged tied to the center and connecting to ground through the pad on the main board.

I popped a switch in the breakout board to check whether leaving these 2 pads unsoldered on the board would allow me to bypass the integrated jumper trace. Other than normal switching continuity, there was never continuity between pads due to the integrated jumper. This is good news with respect to using a bicolor LED!

So here is how I see this going:

1.) Install 1/2 of the Bi LED as normal. The common anode makes connection on the main board to power and one of the cathodes makes connection to the bottom lug of the center switch as normal.

2.) Leave the top and center lugs of the Speed switch unsoldered on the breakout board. This nullifies the integrated jumper. Use the main board ground pad on the Speed switch rail to run a wire to the center lug of the center switch.

3.) Attach a wire to the remaining Bi LED cathode and attach it to the top lug on the Speed switch center switch.

This should look very clean as the wires can be hidden under the Speed switch breakout board. You simply have to suss out which color corresponds to what Speed control.
 

PedalPCB

Admin (Robert)
Staff member
Understood. Just out of curiosity, what was the trouble with how the indication worked out? Wouldn't you just assume a color for each speed control, i.e. Speed 1 = Red and Speed 2 = Blue?

Sure, but it was just as easy to assume LED On = Speed 1, LED Off = Speed 2. It seemed more obvious that the LED near the Speed 1 knob being lit indicated that it was the active control.

Two colors looks cool, it just didn't offer any more clarity as to which mode was selected. If I had it to do over again I'd probably leave the bi-color LED pads in place and let the builder decide.

If you're going to use the breakout board you might consider just cutting the jumper trace, then you can solder all of the lugs and add your jumper wire.
 

Big Monk

Well-known member
Sure, but it was just as easy to assume LED On = Speed 1, LED Off = Speed 2. It seemed more obvious that the LED near the Speed 1 knob being lit indicated that it was the active control.

That's what I figured. Either way it works but not using the bi-color is definitely easier.

If you're going to use the breakout board you might consider just cutting the jumper trace, then you can solder all of the lugs and add your jumper wire.

I thought about this but the ground connection is through the jumper from the top lug. If I cut the jumper, I'd still need a jumper wire to ground for the middle lug. It just seemed easier to leave the board alone and leave those two pads unsoldered.
 

Gordo

Well-known member
Excellent and thanks for the details on lamp ldr placement and stuff.
As I have never had the chance to play an original, what do you mean exactly with 'coolest parts and shortcomings of original'; would love to hear your take on that a bit more in detail. You mentioned noise being an issue?
Thanks Cooder. The original, besides being the size of a loaf of bread, had a slight drop in volume. I think because it had a tendancy to drop a tiny bit off the top and the bottom frequencies it was likely more of a perceived volume loss. The pedal was a bit hissy, although hardly a deal breaker. I always liked it early in the signal chain so that it became a bit more evil sounding than "effect-y". The coolest part was that the LFO was kinda lumpy in a way that I haven't heard many clones capture.

That's not to say that the more modern versions aren't cool, just in a different way. I've enjoyed Bean's Harbinger series as well as a few commercially available pedals.

After doing a bit of reading on the originals I realized that mine was the first gen Unicord version. I always thought it was Univox. I guess they were only made for a short time before Shin-Ei started making them.
 

andare

Well-known member
So, armed with the above comments from @PedalPCB, my multimeter and the Speed breakout board, I did a little research and continuity checking.

The center switch on the Speed board has the top most lugged tied to the center and connecting to ground through the pad on the main board.

I popped a switch in the breakout board to check whether leaving these 2 pads unsoldered on the board would allow me to bypass the integrated jumper trace. Other than normal switching continuity, there was never continuity between pads due to the integrated jumper. This is good news with respect to using a bicolor LED!

So here is how I see this going:

1.) Install 1/2 of the Bi LED as normal. The common anode makes connection on the main board to power and one of the cathodes makes connection to the bottom lug of the center switch as normal.

2.) Leave the top and center lugs of the Speed switch unsoldered on the breakout board. This nullifies the integrated jumper. Use the main board ground pad on the Speed switch rail to run a wire to the center lug of the center switch.

3.) Attach a wire to the remaining Bi LED cathode and attach it to the top lug on the Speed switch center switch.

This should look very clean as the wires can be hidden under the Speed switch breakout board. You simply have to suss out which color corresponds to what Speed control.
If one doesn't solder those two footswitch lugs to the breakout board isn't it possible that they still make contact with the pads?
 

Big Monk

Well-known member
If one doesn't solder those two footswitch lugs to the breakout board isn't it possible that they still make contact with the pads?

I tested that with the breakout board sitting unsoldered on top of a new switch. There was no continuity between the unsoldered lugs in the middle. That is, other than normal switch continuity, i.e. the jumper did not come into play.
 

Big Monk

Well-known member
When I make mine, I’m going to do the bi-color led (no breakout board), and just use a red and a blue chicken head knob for the two speed controls.

That’s a slick idea. Although, I’m sticking with the breakout board because I’m using pin headers to eliminate the hookup wires and make everything look cleaner.
 

Big Monk

Well-known member
Just a heads up: I was putting my order list together for the Paragon Mini, Kliche Mini and Electrovibe. I found everything I needed between Small Bear, Tayda, and Jameco.

Jameco has the 9203 LDRs in stock. They have a $20 minimum on orders or else you get hit with a $10 surcharge so I bought 8 and a couple of Burr Brown ICs for auditioning in my Boss SD-1 once i get an IC socket in there.
 
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