I built this phase 90 amalgamation pedal for a friend of mine a month or so ago. I’ve already had a troubleshooting thread with this pedal, but I got that issue figured out. All was well, the pedal sounded good, so I let my friend take it. Lo and behold, when he got it home and started playing it, the phase was there, he liked the sound of the pedal, BUT! there was a ‘thump’. I told him to try and fiddle with the trimpot, that didn’t help. So, I told him I would fix it for him. When I got it back, it was doing the thump noise, and instead of it just being that noise, it also was like a drastic tremolo. It will go on and off according to the rate of the ‘phase’. I check voltages and such and the biggest problem area is pin 7 of the third op amp. On the multimeter it goes from straight dashes to zero in conjunction with the thump rate. I swapped out the 470k resistor, which didn’t help. I tried a 10uf electro cap in place of the 15uf tantalum and that didn’t help. Tried a different piano, that didn’t help. Does anyone here have any ideas? I’ve provided a couple sound clips and pics of the board, schematic and layout I’ve used. Thank you in advance for any and all help!!!
Issues with a vero XC Phase build!
- Thread starter Drayve85
- Start date
Here are th video clips. One is the one my friend sent me, where the phasing still worked. Then the other is one I just took where it’s a hardcore tremolo on/off with the thump.lol
P.S. apologies for the yt links. Apparently, I either don’t know how to upload videos on here, because when I try to it never works. I wait and wait for it to upload, then it says there’s been a problem. Or PPCB is conspiring against me so I’m not able to upload videos! I feel it’s the latter, myself!
P.S. apologies for the yt links. Apparently, I either don’t know how to upload videos on here, because when I try to it never works. I wait and wait for it to upload, then it says there’s been a problem. Or PPCB is conspiring against me so I’m not able to upload videos! I feel it’s the latter, myself!
mkstewartesq
Well-known member
That sounds a lot like the ticking/pumping problem I had. See my troubleshooting thread here - many of the same issues and if you look at the very bottom, I discovered a way to solve it on mine by replacing one of the ICs with a TL022. Specifically this post. Since then, others have tried it and it worked for them as well.
Mike
Mike
mkstewartesq
Well-known member
Oh, I’m sorry, I missed that part that it was working for a while and then wasn’t. Try my fix but it’s only been tried, in my case and others to my knowledge, where we could never get the pedal to work properly in the first place. I believe someone else had a similar issue (built a pedal for someone else that seemed to work and then it had these issues after delivery) and they were going to try the IC swap but I never heard back as to whether it fixed their issue.
M
Sooo…..I’ve ordered the tl022’s and tried them in the pedal, and it didn’t help out at all! I reflowed all solder joints, and finally got the phasing back. But! Now I’m getting the thump sound with the phasing. Idk what to do now. I was hoping the tl022 swap would work! I’m getting some more 2n5457’s in the mail tomorrow. Imma try swapping in some of them. Maybe the JFET’s are the problem. Thoughts? Anyone??
