Diy Flanger intermittent

[vinceg]

Hi guy, now I have taken taste with Diy and I built a flanger. But when I tried to set it starting from bias trimmer, I noticed that it works intermittently. I'll explain. It works for about 14 sec, after I hear a pop and it is not work for 5 sec, after a pop and it work and so on cyclically. I measured the time with a stopwatch. When I say he does not work, I mean that no flanging effect, no that there is no sound.

If schematic below is not very visible, you can download it http://www.op-electronics.com/it/index.php?controller=attachment&id_attachment=110

[ElectricDruid]

Does the intermittent period respond / correspond to the LFO rate control?

It looks to me like the LFO is pushing the clock to a point at which it can't oscillate. Some combination of adjusting LFO depth and playing with the bias should sort it out.

[vinceg]

For setting the instrutions says:

Start with all the trimmers in the counterclock position. Set the rate at minimum, Range and Feedback at maximum and Volume at 3/4. You should get a clean dry signal.
Turn Bias trimmer up until you can hear flanging effect without distortion. Slowly turn clock trimmer up until you get the widest flanging effect without noise. Slowly turn T1 trimmer up until you can hear the effect going into self oscillation and turn diwn again just before the oscillation point. Keep fine tuning the trimmers while playing until you can find the best setting.

Then the rate control is set at minimum.

[ElectricDruid]

The key part there is "Keep fine tuning the trimmers while playing until you can find the best setting." Lol!

I'd give it a try with the Rate pot set on more than minimum so that I could more easily hear the whole cycle without having to wait several seconds. Like that, you should be able to adjust it so that the clock doesn't cut out.

If not, and you're still having problems, there's probably a problem somewhere in the clock circuitry or the LFO biasing.

[Mark Hammer]

Do yourself a favour and lift one side of either C9 or R16, such that the clean/dry signal is interrupted just prior to the mixing stage.  That way you hear ONLY the wet/delay signal, and can more easily adjust trimmers by ear.

[vinceg]

 Do you mean that I must desolder temporanely one of these components? So it's equivalent to saying desolder one side of RD-ST 5K6 resistor.

[vinceg]

The key part there is "Keep fine tuning the trimmers while playing until you can find the best setting." Lol!

I'd give it a try with the Rate pot set on more than minimum so that I could more easily hear the whole cycle without having to wait several seconds. Like that, you should be able to adjust it so that the clock doesn't cut out.

If not, and you're still having problems, there's probably a problem somewhere in the clock circuitry or the LFO biasing.

You are right. I set the Rate pot more than minimum and I was able to set trimmers. I think it is ok now but I 'm not sure because it is my first time with flanger effect. This clone is a version of Electric Mistress between "81 version and "78 deluxe version with volume pot adding.

[Mark Hammer]

Do you mean that I must desolder temporanely one of these components? So it's equivalent to saying desolder one side of RD-ST 5K6 resistor.

Without checking to confirm the specifically-named resistor, the point is to simply temporarily disable the dry path.  There are many points where one can do that.  Any one is as good as any other.  I would also recommend listening to the signal with headphones.  The general idea is to aurally isolate the sound of the delay path as much as one can so that the impact of tweaking the bias trimmer is as easily-heard as possible.  It's not absolutely essential - it just makes the task of adjusting by ear easier.

[vinceg]

Do you mean that I must desolder temporanely one of these components? So it's equivalent to saying desolder one side of RD-ST 5K6 resistor.

Without checking to confirm the specifically-named resistor, the point is to simply temporarily disable the dry path.  There are many points where one can do that.  Any one is as good as any other.  I would also recommend listening to the signal with headphones.  The general idea is to aurally isolate the sound of the delay path as much as one can so that the impact of tweaking the bias trimmer is as easily-heard as possible.  It's not absolutely essential - it just makes the task of adjusting by ear easier.

I understand. Anyway, I tried to disable temporarily the dry path unsoldering the 5k6 resistor that is in series with C9 cap, but there was no sound, either a clean sound of guitar.

[ElectricDruid]

If you've go no sound with the dry path disabled, then it sounds like the delay line isn't doing anything. There's lots of reasons why that might be the case.

Do you have an audio probe? Can you listen for signals at different points in the circuit?

[vinceg]

Yes, I' ve audio probe but I not know point where signal pass. However I think the delay signal is there. Maybe I had the trimmers down, tomorrow I'll do another test. However I would like to try and set it up as best as possible. How to use the Hz mode multimeter and what points I have to check? Can you tell me the best method to set it by ear and multimeter?

[vinceg]

I think I've finished to calibrate trimmers but I do not know if I make it right. I need help to understand if I set correct the mistress.

[Elijah-Baley]

Hi, I hope you're going to fix your flanger. I bought this PCB, but I have still to buy the rest of the parts to build it.
The build document contains a guide to set the trimmers. Did you follow that?

Maybe you could compare the sound your flanger with some original Electric Mistress or other clones just watching some videos.

[vinceg]

Hi, I hope you're going to fix your flanger. I bought this PCB, but I have still to buy the rest of the parts to build it.
The build document contains a guide to set the trimmers. Did you follow that?

Maybe you could compare the sound your flanger with some original Electric Mistress or other clones just watching some videos.

Yes, I followed the guide to set the trimmers, and the flanger seem sound good and I watched some videos. But I've doubts about sound when the control pots are at maximum. It seems that mine is too much metallic sound than the others and a sound that I can not explain, too confusing.

[DrAlx]

Looks a lot like the madbean current lover.  Basically a 9V Electric Mistress with tweaks.  The problem is one of those tweaks.  A resistor value has been lowered (with the aim of increasing the sweep range) and you are getting those dropouts as a result.  Explained here...

https://www.diystompboxes.com/smfforum/index.php?topic=114014.msg1057251#msg1057251

I would increase R27 in your circuit (the resistor connected to the range pot) from 22k to 39k.
That's the value in the 9V Electric Mistress.

[vinceg]

Looks a lot like the madbean current lover.  Basically a 9V Electric Mistress with tweaks.  The problem is one of those tweaks.  A resistor value has been lowered (with the aim of increasing the sweep range) and you are getting those dropouts as a result.  Explained here...

https://www.diystompboxes.com/smfforum/index.php?topic=114014.msg1057251#msg1057251

I would increase R27 in your circuit (the resistor connected to the range pot) from 22k to 39k.
That's the value in the 9V Electric Mistress.

Ok, I changed R27 resistor with 39k. I tried to set trimmers with Feedback and Range at maximum and Rate at minimum. All trimmers down. First I turn bias trimmer until I hear sound ( dropouts there is and trimmer work about after half), then I turn Clock trimmer and T1 trimmer for oscillating point.
Result: If I turn Feedback(color) control to maximum I hear a metallic bell sound and I also hear the frequency change. Then, if I turn the Range control to half with feedback at maximum I hear a bad sound, then I must turn Feedback counterclock. If I turn all three controls to maximum I hear a bad indefinite sound. Every control pot works fine alone. I think I not be able to set trimmers.

[Elijah-Baley]

Do you want post some pictures?
Are you sure there's no mistake? Did you check every part and connection?

[vinceg]

I'm not sure there is no mistake. But I can check with multimeter some voltage or frequency value if I knew where I check. For example I checked voltage at pin 3 of the V3207 BBD and I find a variable voltage but I do not know the right values.

[StephenGiles]

Flangers are made up of building blocks - broadly speaking, input amp, input filter, BBD, output filter and output amp/ passive mixing with dry signal, and out of harm's way to keep clicks to a minimum - the LFO and BBD clock.

What I would do is this:

1 Carefully remove BBD and keep it safe (I have never been particularly careful and never had a bad one!!)

2 Test for audio at input amp output and input filter output.

3 On the assumption you have used a socket for the BBD, insert a temporary wire link between its input and output pins.

4 Input filter should now be linked to output filter - again test for audio along output audio path.

5 If all is well, test for fluctuating voltage at LFO output.

6 Test for voltage of roughly half supply on each of the 4013 clock output pins (1 & 2), and again on pins 2 & 10 of the 4049 buffers.

I'm guessing that the problem is either the 4013 or the 4049.

[vinceg]

Flangers are made up of building blocks - broadly speaking, input amp, input filter, BBD, output filter and output amp/ passive mixing with dry signal, and out of harm's way to keep clicks to a minimum - the LFO and BBD clock.

What I would do is this:

1 Carefully remove BBD and keep it safe (I have never been particularly careful and never had a bad one!!)

2 Test for audio at input amp output and input filter output.

3 On the assumption you have used a socket for the BBD, insert a temporary wire link between its input and output pins.

4 Input filter should now be linked to output filter - again test for audio along output audio path.

5 If all is well, test for fluctuating voltage at LFO output.

6 Test for voltage of roughly half supply on each of the 4013 clock output pins (1 & 2), and again on pins 2 & 10 of the 4049 buffers.

I'm guessing that the problem is either the 4013 or the 4049.

Please can you show me the points to test in the diagram above? I am not an expert in electronics and I do not know the various stages of the circuit.

Are these the points to check?