DuoPhase no sound on Side A

[Gaenseblume]

Hello,
A Newbie problem: Testing the DuoPhase for the first time the LED on both sides light and change in accordance to the switches and pots, but there is on sound when side A is activated, side B works like I think it should. The wiring is mono in series. Any suggestions on how to solve this?
Best regards!

 

[Dan0h]

Not sure if this is the case for you but I didn’t realize when both leds are on only level2 volume works. Because you are on channel two, and vice versa for channel one when just the one led is on. I was twisting lvl 1 back and forth wanting to hear a change but I had 2 on. Then the “oh!” Moment happened. Hopefully that’s all this is for you as well. Did you adjust the trim pots yet?

 

[Dan0h]

Oops. Saw the word Duo and got excited. I was taking about Duocast you are taking about duophase. My bad.

 

[Chas Grant]

Can you post pictures of both sides PCB and off board wiring to start. One question to start, when side A is on can you see the LED flashing, the LED that turns the LDR's on/off?

 

[Gaenseblume]

 

[Gaenseblume]

The StatusLEDs do flash. One trimpot has a weird orientation (cw when the others are ccw)
So, yes the StatusLEDs and the Yellow LEDs work both.

 

[Chas Grant]

The StatusLEDs do flash. One trimpot has a weird orientation (cw when the others are ccw)
So, yes the StatusLEDs and the Yellow LEDs work both.

As long as both yellow LED's flash then both LFO circuits are working. You can verify this by toggling SW1. SW1 determines which LFO controls the B circuit. When SW1 is up, the B phasor is controlled by LFO A.

I don't see anything crazy with the components, besides the one trim pot, and if the LFO is working the trim pot should be OK. Have you checked voltages to the TL072's? The only DC will be on pins 4 & 8. Pin 4 should be -9Vdc and pin 8 should be +9Vdc. Since they use +9 and-9 Vdc, there is no bias voltage on the inputs, they are referenced to ground where required.

 

[Gaenseblume]

Thank you very much for your thoughts. Tonight I took a fresh start at the DuoPhase and found a defective footswitch causing the trouble. Sorry to have bothered you with my crappy troubleshooting.

 

[Chas Grant]

No Problem glad you got it working