Pedal PCB Phase II not working! Any input is appreciated

[lightbath]

Hello, I recently decided to build a phase II. I built it up and it passes sound in bypass but makes an odd gated buzzing sound when engaged. This is only present when the left trimmer is turned all the way down and the LED is as dim as it will go (see video 1 for sound example).

The LED does not blink. The left trimmer adjusts the brightness of the LED but the right trimmer does not have any effect. (see video 2). There is also a slightly audible pop when swapping from bypass to "on" but I am unsure if this is normal.

After building the first I decided to build the second as I had another board and all the parts. The second phase II is having identical issues so whatever mistake is likely common with both. I have built the closely related "duo phase" before without any issues but this one has me stumped.

Build document linked below:

https://docs.pedalpcb.com/project/PhaseII.pdf

Please let me know if you have any suggestions or need more pictures, readings, or information. Any help is appreciated!

 

[lightbath]

 

[Giorfida]

View attachment 74467View attachment 74468

Can’t see if you are using a TL072 or TL022 as your oscillator (sometimes tl022 work better). I’d first double and triple check component values in the oscillator as well as your soldering though as those are more likely candidates why the oscillator is not oscillating

 

[jakc]

I'm having the same problem with the same board. Yellow LED comes on but no sound when the effect is engaged. The left trimmer does change the brightness of the LED.

I’d first double and triple check component values in the oscillator as well as your soldering though as those are more likely candidates why the oscillator is not oscillating

Would you be able to clarify which components are part of the oscillator?

 

[jakc]

Mine is working!

I replaced the TC1044 with an LT1054.

I don't know if it's just a better chip, or the TC1044that I got from Tayda was bad and the LT1054 I got from Aion was good.

The first time I powered it on after replacing the chip, It still didn't work; it was giving me a very sputtery overdriven sound. Dreading more troubleshooting, I turned it off and on again and it's phasing now. Maybe I need to replace all my op amps from Tayda too? Or maybe it will work forever! The effect sounds alright so far, hopefully it was worth it!

 

[Jer]

I seem to be having the same problem. Everything works its just not oscillating. I tried subbing in LT1054 i happened to have and its the same result.

Anyone have any suggestions here?

I had to sub photo resistors and switched to a green light to match. I dont think the colour of the light would matter for oscillation but correct me if am wrong about that.




Thank you,

 

[jwin615]

I seem to be having the same problem. Everything works its just not oscillating. I tried subbing in LT1054 i happened to have and its the same result.

Anyone have any suggestions here?

I had to sub photo resistors and switched to a green light to match. I dont think the colour of the light would matter for oscillation but correct me if am wrong about that.




Thank you,

Does the green light emit a wavelength in the usable range of your LDRs? Also, did you try it with the lid/bottom on?
I would suggest opening your own thread though.
Edit. I see your other thread now. Is stick to that one. Better for the collective to try to help in one place.

 

[Jer]

Does the green light emit a wavelength in the usable range of your LDRs? Also, did you try it with the lid/bottom on?
I would suggest opening your own thread though.
Edit. I see your other thread now. Is stick to that one. Better for the collective to try to help in one place.

Hey, thanks. Yes i think i used a green light to sync with the LDR’s. They seem to react to the light and it “colours” the tone its just not pulsating. I did try it with the lid on but I figure the light should pulsate open or closed.

Fingers crossed someone has good advice.

 

[eh là bas ma]

I would use an audio probe and check if the signal is reaching the LED/LDRs section, and if it gets out with modulation from there.

Misc > Audio Probe : DIY Fever – Building my own guitars, amps and pedals

[DIY Fever] Audio Probe - very simple contraption that helps with debugging audio circuits

diy-fever.com

Follow the schematic and hopefully the audioprobe will help you find where is the issue. At least it should help narrow it down.

Here is the signal path. In green, it's a portion of the signal path where i would expect to hear clean signal, so you probably dont need to check that part.

See if the signal is modulated around LDR6, that will tell you if there is an issue with this section.

 

[Jer]

@ lightbright

Did you get yours working?

I had a very similar issue which turned out to be the TL 22 in IC 6.

On a whim i swapped the TL 22’s in IC 6 and IC 1 around. That got the light pulsating but with no phase affect. That told me the TL 22 originally in IC 6 was as faulty. I replaced it a new one and instant shine on you crazy diamond.

This seems to coincide with mark up of the circuit diagram provided by eh la bas ma.

Circling back here as I had advised in another post.

 

[Jer]

@ lightbright

Did you get yours working?

I had a very similar issue which turned out to be the TL 22 in IC 6.

On a whim i swapped the TL 22’s in IC 6 and IC 1 around. That got the light pulsating but with no phase affect. That told me the TL 22 originally in IC 6 was as faulty. I replaced it a new one and instant shine on you crazy diamond.

This seems to coincide with mark up of the circuit diagram provided by eh la bas ma

Circling back here as I had advised in another post.