DMD-2 -> Magnetron Echo

falco_femoralis

falco_femoralis

Well-known member
This was my after-family thanksgiving project. I was going to make a kliche with this enclosure but the delay is cooler.

I made it horizontal as it works better with my pedal board.
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Here's a gut shot
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It sounds good. I don't think my Rate control is working properly so I'll have to investigate that. Some of the wires got weird as I ran out of 24ga so I had to use 20ga.

I'm not really into delay pedals and I'm trying to find one I like. I'd like to find a pristine digital delay style pedal like a Strymon Dig.. without paying for one of course.
 
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I removed the Rate pot from the circuit, it tests good. I checked for continuity from the 3.3v source for the CTRL pots and they are all receiving power and are all connected to ground. I checked voltages and the L78L33 is producing 3.336v. The middle wire for the Rate control looked kinked and weird so I desoldered it. Here's the weird part - the middle wire of the 3 CTRL pots all read 0 volts when their pots are all the way counter clockwise, except for the middle lead for the Rate pot, which reads 0.68v. It has continuity to the FV-1 and reads 0.68v there as well. I removed the board from the enclosure and I get the same reading.

This is probably what's throwing my rate control out of whack. It's getting constant voltage from somewhere and ignoring the pot. There's no adjustment when turning the pot and it seems to be stuck in the middle of its range somewhere.

I looked around the board for weird stuff that would cause shorts etc and found nothing. The FV-1 chip gets kinda warm, but not hot by any means. I briefly poked around with the meter looking for shorts and nothing turned up.
 
Welp. I lifted pin 21 of the FV-1 (the one that connects to the Rate pot's middle leg) so I can isolate it from the circuit board. With the pin lifted, it still reads 0.68v. That's disappointing.
 
I LOVE the UA Starlight Delay. Not cheap but damn it sounds good. It does pristine like no other, and also fantastic Deluxe Memory Man sounds without noise. I like it much more than the Strymons I've had. Plus I can easily switch between two different sounds.

I like the layout of your pedal. I wonder if a dud cap could be affecting your rate pot? I have had one or two dead tantalum caps.
 
HamishR said:
I LOVE the UA Starlight Delay. Not cheap but damn it sounds good. It does pristine like no other, and also fantastic Deluxe Memory Man sounds without noise. I like it much more than the Strymons I've had. Plus I can easily switch between two different sounds.

I like the layout of your pedal. I wonder if a dud cap could be affecting your rate pot? I have had one or two dead tantalum caps.
Click to expand...
I'm not really into delay enough to justify spending any kind of money on it. I'm a chorus + overdrive + reverb kinda guy.

The rate pot is connected on one side to the 3.3v regulator and on the other to ground. The middle peg goes straight into the FV-1 chip. I removed the leg that connects to the rate pot and was still getting voltage at the chip - it was internally shorted. I tried desoldering it but it didn't go so well.

I'm rehousing my Mag echo into this enclosure. I almost have it done, just need to figure out the LED.. and the extra hole 🙃
 
I put my Mag Echo into this enclosure as the FV-1 was dead.

The mag echo was one of the first pedals I made. Here's a reenactment of the inside of the enclosure
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Redoing the labels
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I had an extra hole so I made the tone control from the Cataclysm Delay and inserted into pin 3 of the feedback control
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Finally done
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This took forever to work out
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The Depth control on this pedal is a B100k but doesn't do much until it's turned way up. I hooked up the PCB to a breadboard and experimented with different pots. I tried B100k, B50k, B10k, C100k, C50k, but where I ended up was C5k. With this there was gradual sweep thru the entirety of the pot. When I made this pedal the first time I used a B10k but the antilog pots were much better for this application.

I made the LED a bicolor - blue is for bypass and red is the LFO. I set up pots on the breadboard to fine tune the color balance. I ended up with a 7.5k for the bypass LED and a 180 ohm for the LFO LED.

The tone control does nothing. I'm pissed. I thought I put it in the right spot but I guess now. Listening critically to the tone of the pedal, the repeats aren't as hi fi as I'd like. That makes sense given the theme of the pedal but I'd like to have that be an adjustable parameter, like an Age cotrol. I I'll have to revisit the tone part of the circuit and the gain trim pot. It's working currently, and that's good enough for now
 
falco_femoralis said:
I'm not really into delay enough to justify spending any kind of money on it. I'm a chorus + overdrive + reverb kinda guy.

The rate pot is connected on one side to the 3.3v regulator and on the other to ground. The middle peg goes straight into the FV-1 chip. I removed the leg that connects to the rate pot and was still getting voltage at the chip - it was internally shorted. I tried desoldering it but it didn't go so well.

I'm rehousing my Mag echo into this enclosure. I almost have it done, just need to figure out the LED.. and the extra hole 🙃
Click to expand...
I used to be way into delay. Over the past few years I've used it less and less and just used a hint of reverb with my many overdrives. But I still love a good delay. For a long time it was slapback delay I was using as I was in a rockabilly band. And my 6120 still seems a bit naked without a slapback delay. I haven't used chorus as a stand alone effect since about 1988! More and more for me it's just a good low-gain OD. With a good amp and guitar I don't feel the need for much else. I set the Starlight up with a longer delay with modulation as the memory sound and set the manual setting as a slapback. Pretty much all I need and the modulated analog delay sounds are fantastic.
 
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