Please help bring this MUTRON iii to life!!!!

[brokenstarguitar]

Ok guya, I need a little help here on the GGG Neutron (Mutron iii work alike). Here's the link to the GGG site http://www.generalguitargadgets.com/effects-projects/filters-envelope/neutron/ .

No matter what kind of variable resistors I use, I cant get it to sound right, or even close to good. I used 2 LDRs and a superbright blue led at first, then 2 H11F3 Photo-fet optoisolators from smallbear, then, after reading more on the net I found someone, somewhere saying they used a superbright green led and 2 LDRs but still nothing. Then I tried two separate green led and a LDR rolled together, still nothing.

I noticed that the LED stayed on till I strummed then went out, which is the opposite of how it would normally go, or at least I think. So I google searched some other peoples builds and noticed they flipped the led, so I flipped it and now it stays off till I stum. I again tried all the above options and no improvement. With every option I tried different trimmers in "Rx" as well. A 10k, 5k, 1k.

So I thought maybe if I swap the opamps (U1, U2, U3) with others it would come to life but I was wrong. I tried 082, 062, 4558, and a few others. I'm so lost with this. I'm using a 200k pot for PEAK and a 1MC for Gain. A rotary 3 potion switch for MODE and dpdt toggles.

If anyone can help me breath some life into this Id extremely appreciate it! I took my voltages and this is what I came up with.

Power Supply
9.55v

U1
1. 1.0mv
2. 2.9mv
3. 3.0mv
4. -8.67v
5. 0.3mv
6. 3.1mv
7. 3.1mv
8. 9.43v

U2
1. 4.9mv
2. .6mv
3. .3mv
4. -8.68v
5. .3mv
6. .9mv
7. .4mv
8. 9.43v

U3
1. 7.7v
2. 3.83v
3. 3.8v
4. -8.68v
5. .3mv
6. 1.6mv
7. .37v
8. 9.43v

U4
1. 4.84v
2. 4.68v
3. 0
4. -4.35v
5. -8.68v
6. 5.39v
7. 3.62v
8. 9.43v

[idy]

"...LED stayed on until I strum..." probably meant the "direction" switch was in "down" instead of "up" mode. You probably had the LED in right the first time. Probably doesn't matter, since you are just reversing the action of the switch.

What exactly is it doing? Sweeping? The LEDs are lighting but...?

[R.G.]

Likewise, I'm confused by your problem description.

1. Does sound come through at all in both effect and cancel positions?
2. If sound comes through it in the effect position, does it sound different depending on the high/low/band pass switch settings?
3. Do the LEDs change brightness more or less following the loudness of the note as it decays away?
4. Are you covering the LDRs so that room light can't get to them to swamp out the light from the LEDs?

[brokenstarguitar]

Likewise, I'm confused by your problem description.

1. Does sound come through at all in both effect and cancel positions?
2. If sound comes through it in the effect position, does it sound different depending on the high/low/band pass switch settings?
3. Do the LEDs change brightness more or less following the loudness of the note as it decays away?
4. Are you covering the LDRs so that room light can't get to them to swamp out the light from the LEDs?

Sounds comes through and it wants to phase but wont. Right now I have the H11F3s in so definately no light getting to them. I get more of it trying when the 2ldrs and green led are in though, if that makes sense. And yes, all the controls seem to be working, i did notice that the GAIN control acts like a volume somewhat, not sure if that's normal or not. When the GAIN is fully counter-clock ways there's no sound what so ever. Now to answer your question about the led brightness, (know that the led is oriented as per the layout. I tried it the otherway just hoping that was the issue cause of the photos I found) Now, with the 2 ldrs/green led, the LED stays on, brightness about 80%, the bightness increases as the note goes in then dims down to the 80% as the note decays.

[idy]

Try answering all of RGs questions.

[brokenstarguitar]

Likewise, I'm confused by your problem description.

1. Does sound come through at all in both effect and cancel positions?
2. If sound comes through it in the effect position, does it sound different depending on the high/low/band pass switch settings?
3. Do the LEDs change brightness more or less following the loudness of the note as it decays away?
4. Are you covering the LDRs so that room light can't get to them to swamp out the light from the LEDs?

Sorry, I thought I did answer all the questions. Lets see....

1. Cancel position I'm assuming is bypass? With that in mind, sound comes through in effect and cancel positions. I get signal in every switch position possible, just not a phase/sweep.
2.

Sounds comes through and it wants to phase but wont. Right now I have the H11F3s in so definately no light getting to them. I get more of it trying when the 2ldrs and green led are in though, if that makes sense. And yes, all the controls seem to be working, i did notice that the GAIN control acts like a volume somewhat, not sure if that's normal or not. When the GAIN is fully counter-clock ways there's no sound what so ever. Now to answer your question about the led brightness, (know that the led is oriented as per the layout. I tried it the otherway just hoping that was the issue cause of the photos I found) Now, with the 2 ldrs/green led, the LED stays on, brightness about 80%, the bightness increases as the note goes in then dims down to the 80% as the note decays.

Sorry, I thought I did answer all the questions. Lets see....

R.G.: 1. Does sound come through at all in both effect and cancel positions?

ME: 1. Cancel position I'm assuming is bypass? With that in mind, sound comes through in effect and cancel positions. I get signal in every switch position possible, just not a phase/sweep.

R.G: 2. If sound comes through it in the effect position, does it sound different depending on the high/low/band pass switch settings?

ME: 2. The sound does sound different depending on the high/low/band pass switch.

R.G.: 3. Do the LEDs change brightness more or less following the loudness of the note as it decays away?

ME: 3. The leds brightness gets less as the the note decays away.

R.G.: 4. Are you covering the LDRs so that room light can't get to them to swamp out the light from the LEDs?

ME: 4. When I have the 2 ldrs/green led combo in they are covered. A dab of glue holds all three together, then theyre wrapped in aluminum foil, then wrapped in heat shrink. When I ut the H11F3 optoisolaters in theyre also covered in the DIP packaging.

[idy]

So they LEDs are wrapped up... Any way to twist the trimmer and see if you can get more sweep out of the LED? Its not a by eye thing. The photocell has a different response than the eye... and this is happier set "by ear."

You said you tried all kind of trimmer in there... what did you end up with?

And did you try hooking up a booster between guitar and filter? Helps a lot of times...

[brokenstarguitar]

So they LEDs are wrapped up... Any way to twist the trimmer and see if you can get more sweep out of the LED? Its not a by eye thing. The photocell has a different response than the eye... and this is happier set "by ear."

You said you tried all kind of trimmer in there... what did you end up with?

And did you try hooking up a booster between guitar and filter? Helps a lot of times...

I do not test by eye. I have it hooked up to my test box, into a practice amp. So everytime I swap or try something new I'm listening AND watching. I haven't decided on a trimmer et yet because no matter which I try it wont sweep. Everytime I try something new I try it with all the previously said trimmers ( 1k, 2k, 3k, 5k, 10k). I havent tried hooking up anything between the guitar and filter. By filter do you mean the effect? What kind of booster should I try?

[idy]

You must have something in the position of the LEDs resistor. Madbean has a 5k with a 330ohm limiter. 5k should be fine, but at max you could maybe burn out the LED.

Yeah, the filter is the effect, the mutron. Try any kind of cleanish booster first to drive it harder and see what happens when you give the Neutron a couple of volts worth of envelope to follow (or at least be triggered by). Could even use an overdrive (high volume, low drive or distortion) but a clean booster will keep dynamics.

And you didn't attach a photo yet did you?

[brokenstarguitar]

Hey guys. Sorry I had computer issues and couldn't log on. Now in the meantime I built another one and I'm having the same issues so I'm thinking my wiring HAS to be wrong somewhere. I've been going over it, over and over and over but I don't see anything wrong. The only difference from my build and the GGG wiring layout is I dont have the negative from R20 going to a stereo jack cuz it's on my test rig, but I do have it grounded. I did hook everything up according to the GGG wiring layout when I first started this thread but that still didn't matter.

You must have something in the position of the LEDs resistor. Madbean has a 5k with a 330ohm limiter. 5k should be fine, but at max you could maybe burn out the LED.

Yeah, the filter is the effect, the mutron. Try any kind of cleanish booster first to drive it harder and see what happens when you give the Neutron a couple of volts worth of envelope to follow (or at least be triggered by). Could even use an overdrive (high volume, low drive or distortion) but a clean booster will keep dynamics.

And you didn't attach a photo yet did you?

I took my Nage Viper booster and put it before the Neutron but that didnt do anything. Here's a few pictures. If a video would help, I could upload one without a problem. I appreciate you guys trying to help and again apologize for the delay in my reply.

[idy]

I don't see the LED/LDRs trio heat-shrinked... Sure that foil didn't do anything bad? Why aluminum foil and not just heat shrink?
You have two identical boards not working the same way.

[brokenstarguitar]

I want to use the H11F3 optos, which is in both boards. The led/ldrs I used to make sure the leds were lighting like they should. And after testing the tin foil has not caused any issues.

I read somewhere to wra them in aluminum foil as well as heatshrink. But keep in mind that I made 2. One with and one without foil.

[slacker]

What you could do to try and see if the filter part of it is working properly is remove the H11F3s and put resistors between pins 4 and 6 of the sockets. Use the same value for each one and try different values say 100R 1k, 10k, 100k, different values should give different sounds, it's just setting the filter to different frequencies. This will let you see if all the controls are working correctly.
If it seems to work it means the problem must be to do with the circuit driving the LDRs or maybe the LDRs are bad.

[idy]

We know that at least with green LED/LDR the led is lighting up to follow the envelope. Not a problem in this part of the circuit. Although changing to H11FC could be suboptimal.
We know the filter part is working because it changes when he changes the filter range switch.
I like the idea of Slacker, maybe two pots or a dual gang to replace the LDRs. Can you sweep the filter like this?

Also: I have trouble seeing clearly the wiring to the mode (HP/BP/LP) switch. I'm sure you've really checked it out, but verify for me where the wires are coming from?

You're very close to having two working mutrons.

[brokenstarguitar]

Ok, I took the H11F3s out and ran the leads out to 3 different value pots (just to be 100%), 1k, 10k, and 100k, and I can sweep the frequencies with everyone. I tested both boards and both pots were fully functional on both boards. So I'm guessing, going off of what Slacker said, it would be the circuit driving the ldrs?

Idy, I forgot to write down where the HP/LP/BP switch wiring but I'll check again in the morning. I mean I've went over it a thousand times and sure it's correct but once more won't hurt. And who knows, maybe the wiring diagram I'm following is wrong or something and I haven't noticed. I have caught a few differences in other layouts/schematics before and actually caught one on this one as well including the 4.7uf tantalum placement.

I just wanted to give yous a little update on the progesterone incase yous think or anything. Thanks guys, I appreciate your help.

[idy]

There is some missing link, it seems like the vactrol/h11f1/ledldr. The envelope generator is sending a signal to the LED. The filter sweeps when you put a variable resistance in place of the "vactrol." But lighting up the LED is not making the "vactrol" change, or the vactrol's connection to the filter is not good.

1)You are getting a signal to light up an LED (but you can't see inside the H11F1 so you are not sure it is now)

2)The thing the LDRs control, the filter, can be worked by jury-rigging a variable resistance across it/in place of it;

3)But turning that LED on that LDR is not giving you results.

What are your "on" or "light" resistances like on the LDRs(photo MOSFETS)? Measure this resistance  when you are feeding "program" (signal) into the filter and also when signal is not present. (You have to unbend the LDR terminals, terminals 4 and 6 on the H11F, from the sockets.)

There is a bit of play as to the working values of the LDR because they are in parallel with fixed resistors (220k) so the thing will see a value between slightly under 220k and slightly under the "light" or "on" resistance of the control element.

I am not so interested in the wiring of the mode switch anymore, focusing on the LDR/LED. (or LED and light sensitive MOSFET in a H11F1.)

[brokenstarguitar]

Not sureif I'm doing something wrong or not but my DMM shows no reading, not even 0. When I send a signal through the circuit it jumps up to about 40k on pins 4 and 6 (35k on board 2) of the H11F3s.

I have the boards hooked up as if I were testing the circuit but have pins 4 and 6 bent up out of the socket. Is that correct? And i'm testing the pins not the socket side.

[idy]

You are testing correctly (pins 4 and 6, bent up, testing chip/vactrol and not socket) but... I think you are confused by your meter; it is probably giving a very high reading when dark, coming down to 35-40k when you apply signal. Reversing the "Sweep" or "Direction" switch should reverse that.

You will see a very high value when the LED is dark: my meter gives a "1" with no decimal to show that a reading is too large to read (it should be on the order of many mega-ohms when dark. My meter reads up to 10M and shows all my dark LDRs as open circuits. Even the ones I specifially bought to be like 2M.)
When the LED lights up you should see a value that is lower, maybe several K ohms. 40k seems too high. LED not bright enough? Can you tweak your resistor to get it brighter again?

[marshal2107]

Any news on this?  I'm having the exact same problem.  Leds move around with the envelope, but no sweeping happens.  I have tried openening up the ldrs, and y try to sweep them with a flashlight, but I don't get any frequency sweep.  If I give too much light It starts buzzing or oscilatting around 10k.  In a softer flashlight move, all I get is a variation in volume. Like it's working as a tremolo instead of a filter.  Also with the less pointing to the ldrs, I don't even notice a variation in volume.  This with the schematic " up position". The actual behaviour is that when I strum the light goes off for a glimpse of an eye, whether that's right for up or down position I don't know yet. 

Any clues?