Build Your Own Clone Message Board

Okay, so it's got a lot more parts than I had originally planned, but I think you guys will enjoy this circuit. It's the same LFO as the trem I just posted.

I think there are some tweaks to go still on the LFO, but it works very nicely as presented. Slower speeds sound like a nice, classic phaser, although it is a little on the "throbby" side. Faster sounds more like a tremolo with a *hint* of pitch bend.

Ramping up to four stages wouldn't be that hard, but I was trying to keep it as simple as possible and still sound like a phaser. I'll probably do the four-stage version, but not until I get the LFO closer to perfect (if that ever happens).

You can add a switch to kill the dry and get a more vibrato-like sound. But it's hard to hear it at slow speeds, and it's too choppy sounding at higher speeds. It was hard to tweak everything for both phaser and vibrato sounds, so I just focused on the phase.

This is definitely one to tinker with if you're a breadboard kind of guy. So consider this one about 95% done (and quite usable as is).

Little update: The "Shape" control doesn't really do much in this application, so I'll remove it. Yay, less complexity!

Anyone done a vero or perf for this? Still haven't built my testrig chopping block

What's with R22?

A misguided attempt at introducing some feedback.

Any update on this CJ?

I've got it sidelined at the moment. I'm working on a couple "for money" layouts right now. Once those are finished, I'll get back to doing fun stuff.

No stress Forrest, just curious

Final schematic is below.

Note, on the PCBs I had made, there is a missing connection that requires a short piece of jumper wire to fix. On the bottom of the PCB, connect the junction of R1/R8 to pin 8 of IC1. It's an easy fix and won't be visible on your final build. That's it!

If you want a vibrato effect, omit R13. Or put it on a switch. Or maybe use a pot in place of R13 so you can dial in how much pitch-bendy goodness is available.

Built it..........and it does'nt work.....all i get is an un-effected signal, no LED ticking at all.....i first tought that the pads may be reversed.......but they are not...

My first CJ fail........., feels really bad....

You'll get it working. I built one on the same board as you, so I know it actually works.

Ok............., so i got my LED to lit up, but only when the Depth pot is fully clockwise..........other than that i get a perfectly clean signal coming out of it when engaged.............any pointers on what to look at.

Also, would it be possible to post a picture of the PCB, now that it,s fully populated......it's pretty hard to see the part names........

Thanks.......

Here you go. I was about to populate mine so I scanned it first for ya.

Thanks alot Morgan!

I can now start my most hated DIY activity............troubleshoot.........AAAAAHHHHH!!!!

I've got the same symptoms as you Rej. It's odd because my voltages are fine on the opamps, and you should get clean signal even if the LED/LDR system isn't working. I'll hit the signal tester tomorrow.

CJ - any specifics on the LDR/LED combo? I started with a 5mm diffused yellow LED and it wasn't blinking that I could see, even though my LFO seems to be LFO-ing fine. I'll try some different ones tomorrow.

Did you guys do the jumper fix on the bottom of the PCB?

Yeah, but that just sends power to the LFO anyway, right? I wouldn't see it blocking dry signal. I doubt the two issues Rej and I are having are related; we were probably both just going too fast.

It provides power to the voltage divider that biases the LFO, yeah.

It would have no effect on dry signal at all.

I just fired mine up and it sounds actually not to shabby. I've added a few mods to mine to get the most out of it:

• Put a switch in series with R13 to make/break the R13 connection (this is basically wet/dry or a vibrato/phase-trem mode selector). You could also use a pot in place of R13 for more control over the mix of pitch shifting vs phasing.

• I also replaced R5 with a pot to help dial in the speed range. It helps to adjust this when switching from vibe to phase-trem. It's not really necessary, but maybe you will find it useful. At least that's why I think I did it. I'm not 100% sure, honestly.

• I put a 680R resistor in parallel with the Depth pot. I don't recall doing this, and I'm not entirely sure why (other than to mess with value/taper). I'd skip this one just in case.


For LED, I used a 3mm diffused (yellow, if it mattes). The LDRs are the small type from Tayda.

I just put this together and it's working and sounding pretty good.
I put R13 on a switch. Tried a 10k pot, but either didn't do it right or it wasn't very useful.

But I was curious about one thing... I didn't have a 4558 IC, so I subbed a TL072.
Just curious if you played around with op amps and if you recommend grabbing a 4558 instead?
Not a big deal, like I said, it's working and sounds cool... but I haven't heard a demo of this, so I'm not sure if I'm missing out on anything by using the TL072 instead.

Thanks!

The 4558 is what runs the LFO, so it won't have a *tonal* change over a TL072. But the 072 might work better (or differently) in the LFO, so it could give you a different sweep (which would sound different).

Cool, thanks. I'll go ahead and grab a 4558 next time I place an order and see what it does.
I found the sound is best with the depth all the way up (or down? Whichever one means the most depth) and the speed about 80% up. So I'd be interested to see if I could get a little more depth and maybe a touch more usable room on the speed knob. (it goes from "that sounds good" to "way too fast/choppy" pretty quickly.) I was thinking about trying to mod it to change those ranges, but maybe just a different chip will get me where I want to be.

I also used a water clear 5mm green LED. But I was thinking of changing it to a 3mm so I could control the angle a little better between the LED and LDRs.

Anyway, thanks for the reply and the cool circuit.
I seem to recall you worrying that people would think it wasn't anything too special, but I actually really like it.

Just a follow up... turns out I did have a jrc4558 laying around. It was in the wrong drawer.

Anyway, yeah.. that does give a better sweep, IMO.
Changing to a diffused yellow LED also helped smooth it out and get a little more depth.

So there you go. I'll be boxing this one up next week and taking it down to practice.

Nice! Glad you got it working better.

Do you have time to record a clip of it?

Not right at the moment, but I should be able to do a clip in the next couple days if you're interested.