Mc Beat (Lovetone Meatball) distortion

[chikyjudas]

Hello people
I am working with the Mc Beat (Lovetone Meatball) from Pisotones:
http://www.pisotones.com/Meatball/psst/meatball-psst.html

I am doing it in my protoboard (breadboard for some people) with some different stuff. For example, I am using 2xTL072 instead of TL074 and I am using 2 difused green leds with 2 LDR (with 50k to 100k on light resistance).

My problem is that it is difficult to configure the pedal to sound like the Pisotones examples. And most of the configurations sounds like clipping signal or it doesnt even sound. I dont know if I made a mistake in the protoboard (which I have searched for it like 5 times and nothing). Maybe the leds or the LDR? I have tested many and nothing change this conditions maybe a little better but nothing good. I have tried with H11F1 opto too, but the same result, a lot of distortion.

I dont have an oscilloscope right now, so it is kinda hard to look where is the problem.
Any ideas?

[bluebunny]

Welcome!

The TL074/TL072 swap is fine.  Often easier to wire up two duals rather than one quad.  If you're rolling your own Vactrol, is it light-tight?  If you've got both halves naked and open to the world, then the ambient light will stop it working.

[PMowdes]

Hello people
I am working with the Mc Beat (Lovetone Meatball) from Pisotones:
http://www.pisotones.com/Meatball/psst/meatball-psst.html

I am doing it in my protoboard (breadboard for some people) with some different stuff. For example, I am using 2xTL072 instead of TL074 and I am using 2 difused green leds with 2 LDR (with 50k to 100k on light resistance).

My problem is that it is difficult to configure the pedal to sound like the Pisotones examples. And most of the configurations sounds like clipping signal or it doesnt even sound. I dont know if I made a mistake in the protoboard (which I have searched for it like 5 times and nothing). Maybe the leds or the LDR? I have tested many and nothing change this conditions maybe a little better but nothing good. I have tried with H11F1 opto too, but the same result, a lot of distortion.

I dont have an oscilloscope right now, so it is kinda hard to look where is the problem.
Any ideas?

Some more information would be useful, and maybe some pictures.

I've built a fair few of these and I use vtl5c3's which work fine.  I think the originals used 2M dark resistance LDR's with diffuse green 5mm LEDs.

The most important part to source is the LM1458.  There are lots of fake chips out there, make sure you buy good ones form a reputable supplier (avoid Chinese / ebay ones and cheap IC's).  You wont get the thing running without this at all.

Another good indicator is with the blend knob.  the audio path is fairly short, do you get dry signal with the blend pot fully CCW?

Does your trigger circuit work??  you should see the trigger led light up when the trigger is set to down, with the trigger set to up it should flicker when the sensitivity knob is fully clockwise and you strum your gguitar

another thing to check is that you have to send / return wired correctly.  if you don't have the switch / tip connected your signal wont pass to the filter

[chikyjudas]

Hi guys, I will try prototiping the Mutron 3, it is a little bit different.. and then if it is works, I will try this one again or just add the same features.

I am using MC1458, I think it is similar to the LM1458. I have tried the TL072 too but I didnt get the solution.

The blend knob it is ok. I get the dry signal.

The leds works. I am using 3mm difused leds. I can try with 5mm.

Do you know which is the minimum resistance? The maximum are always similar like 1Mohm or something for LDR, it doesnt matter that much because the LDR has a parallel resistor in the circuit, so, with no light will be similar to this resistor. But the minimum are different. I am currently using 10k-50k minimum resistance of LDR.

The send/return are wired correctry I think because the leds varies the light. But I get distortion when I play.

Could be maybe that I need a first stage of gain? Like in Mutron 3?