SOLVED Duo-Phase Ticking (mainly when left side is engaged)

[jwyles90]

Hey all!

I just finished putting together this Duo-Phase, and everything is working as it should except I'm getting a fair amount LFO ticking from it. It happens the most prominently when the left side (looking at the front of the enclosure) is engaged, or when it's bypassed altogether. If I've got the right side engaged, or both at the same time, it's virtually nonexistent.

I went through and looked at all the other troubleshooting threads with this similar issue, and it seems that moving the wires around can sometimes help. I gave that a shot, and even tried using some shielded wire on the in/out jacks, and it didn't really seem to mitigate the issue all that much. I've also never used shielded wire, so there could very well be something to it that I'm unaware I need to do to make it function properly.

I suspect that I might also be getting some noise from the switched jack input wire, since it impacted the ticking a bit when I moved it around while it was plugged into my amp. I'm going to try rerouting all the wires that run the length of the enclosure to go underneath the PCB when I get home from work today, but in the meantime, I was wondering if there was anything else I could look for or try to do that maybe I'm not spotting or thinking of. Thanks in advance for all your help!!

 

[Giorfida]

I attached a wire from the shield to the ground lug on the input jack, and then another one from the output wire to the ground part of the footswitch. Should I just ground one of them?

And I just used it for the main in/out jacks. It's a lot more clunky to work with than I thought, and I've gotta wrap everything in heatshrink to stop it from touching the enclosure/other components and grounding the whole circuit. I'd hoped that just the main in/out wiring would be enough, but I can try using shielded wire for the other two jacks as well.

Since it’s 2 discrete phasers, both sets of input jacks would need shielding OR run a distance away from any board components. I see the wire from the right side phaser (left side if looking at components) apppears to be running along the bottom of the board right by the oscillator for that section

 

[jwyles90]

Since it’s 2 discrete phasers, both sets of input jacks would need shielding OR run a distance away from any board components. I see the wire from the right side phaser (left side if looking at components) apppears to be running along the bottom of the board right by the oscillator for that section

So this is how I've got it wired currently:

I tried to ensure that all the wires that weren't shielded were running underneath the board and away from the LEDs. The input wire from the switched jack is running underneath it and on the left side of the switches. I'd hoped that would be enough to get rid of the ticking but it's seeming like it doesn't want to cooperate.

 

[Giorfida]

So this is how I've got it wired currently:
View attachment 73845
I tried to ensure that all the wires that weren't shielded were running underneath the board and away from the LEDs. The input wire from the switched jack is running underneath it and on the left side of the switches. I'd hoped that would be enough to get rid of the ticking but it's seeming like it doesn't want to cooperate.

If it’s touching the board it could be picking up the oscillator (the tl072 very top left looking at that pic). As someone else mentioned, if you have any tl022, you could try one of those in that spot.

 

[jwyles90]

If it’s touching the board it could be picking up the oscillator (the tl072 very top left looking at that pic). As someone else mentioned, if you have any tl022, you could try one of those in that spot.

Ah yea, I swapped out both the oscillators for 022s already. It definitely helped lower the ticking noise but didn’t get rid of it entirely. I’ll try wiggling some of those wires around to see if maybe they’re touching the underside of the board

 

[andare]

I attached a wire from the shield to the ground lug on the input jack, and then another one from the output wire to the ground part of the footswitch. Should I just ground one of them?

And I just used it for the main in/out jacks. It's a lot more clunky to work with than I thought, and I've gotta wrap everything in heatshrink to stop it from touching the enclosure/other components and grounding the whole circuit. I'd hoped that just the main in/out wiring would be enough, but I can try using shielded wire for the other two jacks as well.

AFAIk you should only ground the shield at one end and that's at the jacks, where it actually goes to ground

 

[jwyles90]

AFAIk you should only ground the shield at one end and that's at the jacks, where it actually goes to ground

I'll give that a shot! I've also found that putting my Informant overdrive before it gets rid of the ticking entirely, so I'm planning on putting a little buffer circuit in there as an always on type deal.

This is a whole other can of worms, but I'm going to try a jfet buffer first since those tend to be the smallest size-wise. I have a feeling that the duophase might be particular to what kind of buffer eliminates the ticking though. If that's the case, it seems like the buffer in the Informant overdrive is a 072 based one, if I'm reading the schematic correctly?

 

[Giorfida]

I'll give that a shot! I've also found that putting my Informant overdrive before it gets rid of the ticking entirely, so I'm planning on putting a little buffer circuit in there as an always on type deal.

This is a whole other can of worms, but I'm going to try a jfet buffer first since those tend to be the smallest size-wise. I have a feeling that the duophase might be particular to what kind of buffer eliminates the ticking though. If that's the case, it seems like the buffer in the Informant overdrive is a 072 based one, if I'm reading the schematic correctly?

Just a thought. If buffering the input helps, it’s telling that the noise is definitely picking up noise on the input wires— buffering is likely changing the impedance or boosting it enough that the signal is more immune to the clock noise.

 

[jwyles90]

Just a thought. If buffering the input helps, it’s telling that the noise is definitely picking up noise on the input wires— buffering is likely changing the impedance or boosting it enough that the signal is more immune to the clock noise.

Yea that a good call. I'll try grounding just the input shielded wire and see if that fixes it, or maybe running the wire underneath the board rather than above/to the side.

 

[andare]

Yea that a good call. I'll try grounding just the input shielded wire and see if that fixes it, or maybe running the wire underneath the board rather than above/to the side.

You should ground every shielded wire at this point because the shield left ungrounded is an antenna for noise.

 

[jwyles90]

You should ground every shielded wire at this point because the shield left ungrounded is an antenna for noise.

So I've grounded them all and it doesn't really seem to make a difference. The ticking is still coming through regardless of whether the shielded wire is grounded or not. I even swapped out the shielded input wire for a normal wire and it still had the same amount of ticking.

I built a couple different buffer boards (one jfet, one op-amp) to see if that would help. The jfet one didn't do much, and the op-amp one definitely helped but it's still there. I might try to figure out a vero layout for the buffer that's in the Informat overdrive, since running that pedal specifically before the duo-phase cuts out all the ticking entirely.

 

[Erik S]

I've grounded them all and it doesn't really seem to make a difference.

Mom tried grounding me.

Also didn’t make a difference.

 

[jwyles90]

Mom tried grounding me.

Also didn’t make a difference.

Honestly at this point we should all know better.

 

[Erik S]

I wonder about the wires running under the board. I know you’ve already rewired this a buncha times, but I wonder if getting them up closer to the lid might help.

 

[jwyles90]

I wonder about the wires running under the board. I know you’ve already rewired this a buncha times, but I wonder if getting them up closer to the lid might help.

Like just moving them up to the 'top side' of the board? I originally had them all on the component side of things and was still getting a fair amount of ticking.

 

[Erik S]

Like just moving them up to the 'top side' of the board? I originally had them all on the component side of things and was still getting a fair amount of ticking.

Yup. Like how you had it to begin with, but experimenting with what components on the board the wires are near/ touching. A smarter builder than me could probably tell you what parts you specifically would want to stay away from.

Under the board like you have them now seems like the closest you can get to the circuit, and the hardest to control/ tell where the wires are.

Maybe you could even tack on some temporary long wires and manipulate them toward and away from different parts and figure out where the noise hot spots are.

 

[andare]

There are tons of modulation pedals on the market and none of them tick. What magic are we missing?

 

[jwyles90]

Alright so I'm marking this one as SOLVED. I feel a little silly, but after all the buffer building, shielded wire mishaps, etc., I just completely re-did all of the wiring and the way it was laid out. I tried out @Erik S 's suggestion of having all the input and output wires be much longer than needed, and then tried moving them around in a variety of ways until I was able to get them each in a spot with the least amount of noise. Then I cut them down to the appropriate size so that they'd stay in place.

As it is now there's basically no ticking. Maybe a sliiiight bit of it if I've really got my amp turned up but otherwise it's pretty much silent. I think the biggest culprits were both the input wire on the main input (which was running right alongside the oscillator) and the switched jack input that was running underneath the other one. Thanks for all of your help those who commented! I'm glad to be able to set this one down and just play it now, rather than fuss and obsess over the wiring. I'll have a build report soon once I get a chance to record some clips of it, cause it sounds freakin awesome.

 

[Erik S]

I felt bad suggesting you tear it all apart again after all the work you put in, so I'm stoked it worked out!

 

[jwyles90]

I felt bad suggesting you tear it all apart again after all the work you put in, so I'm stoked it worked out!

No need to feel bad! It was a good suggestion, and I was getting to the point of needing to do that anyways. This whole process was a good lesson in how LFOs generate noise and how to run wiring with particularly noisy builds.

 

[jwyles90]

Also, a friend suggested I try building one of these to isolate the noisy spots on the board. I didn't end up building one but it seems like a useful tool for helping figure out where to avoid putting wires. If anyone is interested.