Duophase Parallel to one output?

[jpd]

Hi all.

So, I drilled an extra hole for a DPDT switch that I was hoping to use to make a series/parallel switch for the Duophase.

Series operation seems to work fine, parallel just squeals at me. I feel like I'm just overlooking something obvious, wondering if someone has input here.

Going from input jack A to the in lug of footswitch A, another wire in the same lug out to the common on one side of the DPDT. The series side has nothing soldered to it. The parallel side goes out to the in lug on footswitch B. My thinking is that both sides get the same input (like the IN A setting on a true Biphase)

The other side of the DPDT has the out lug of footswitch A going to the common lug of the DPDT. The series side goes out to the in lug of footswitch B. The parallel side goes to the output jack.

So my thinking is, parallel splits the inputs to go out to the in lugs of footswitches A and B, and gets both footswitch out lugs to the output jack. Series just goes as normal, in lug of footswitch A, out lug of footswitch A to in lug of footswitch B, then the summed out lug of footswitch B to the output jack.

Series wiring works like a charm. Parallel just gives ringing pulsing feedback. Any input on this would be appreciated. I can try to upload a pic when I get home later, if that is helpful.

 

[jpd]

Update: I'm an idiot. I'm trying to run two separate phasers to the same jack. I am pretty sure this will never work.

 

[Jovi Bon Kenobi]

Not that it helps with your issue but the 5mm type 1 bezels PedalPCB sells fit perfectly in toggle switch holes. Same size drill holes.

 

[Chuck D. Bones]

Update: I'm an idiot. I'm trying to run two separate phasers to the same jack. I am pretty sure this will never work.

Actually it should work, R29A & R29B act as a blend and keep the outputs of the two phasers from fighting. I'd make those two resistors bigger, like something in the range of 4.7K to 10K.

From your description, I'd guess you have the output of one phaser feeding back to it's input. Like my sig line says...

 

[jpd]

I ended up just running the parallel output to a second jack, so 1 in, 1 out for series, 1 in, 2 out for parallel. I have another PCB here, might try experimenting with those values on R29 as mentioned. Thanks for the advice there. Otherwise, this was a super painless build.