Duo-Phase Series-Parallel Switch

[moosapotamus]

The Duo-Phase operates with the two phasers always in series. I'm thinking it would be cool to add a Series/Parallel switch. Something like this...



Seems kinda like a simplified version of the Phaser B input switch on the Mu-tron.

Moving on to add the dual inputs/outputs raised a few questions for me. Looking at the PPCB wiring diagram for two inputs / two outputs, it looks like you get the output of phaser A only from the first output and a series mix of both phasers from the second output. Am I seeing that correctly? Might be cool, instead, to have only phaser B in the second output.

Here's what I'm thinking...



With nothing plugged into either Out A or In B, the Series/Parallel switch works just like above. And I'm thinking that Out A should be a switching jack, just like the In B jack. Because If I am tapping Out A, I don't think I would still want Out A to continue on and mix with In B. I would want to have just phaser B at Out B. Switching to Parallel mode would do it, only phaser A at Out A and only phaser B at Out B. But then using Out A and In B with the switch in Series mode causes some minor inconveniences. Plug in to Out A and no input signal reaches In B. And using In B becomes just like bypassing Phaser A. But maybe that's just fine... Want to use the additional I/O jacks, switch to Parallel mode.

Does that make any sense? Any thoughts, concerns, or other ideas?

 

[moosapotamus]

I am curious to know from others that have already built the Duo-Phase with the extra I/O, how often do you really use the Phasor B input, and how do you actually use it? I'm thinking of leaving it out because, other than mixing two different instruments together, I'm not seeing how else it could be used, and I don't think I would do that very often. I do plan to keep the separate Phasor A output for stereo operation. But what would I really be giving up without the Phasor B input?

 

[moosapotamus]

So, anyway... I am excited to build the Duo-Phase. Got the PCB, finally ordered needed parts and started working out how to do a couple other mods I'm interested in trying. But I've hit a roadblock.

The reference designations in the PCB layout image on the first page of the build doc seems to be reversed compared to the wiring diagram and schematic. Part numbers are all appended with either 'A' or 'B', appearing to indicate Phasor A (on the right) and Phasor B (on the left). But if that's correct, then the wiring diagram shows the guitar input being wired to Phasor B first. But the schematic shows the input going to Phasor A first. Is this just a typo on the PCB, or am I just needlessly confused? Thx!

 

[moosapotamus]

OK, got it (duh). Input goes to phaser B first, then to phaser A. I got confused going from left to right on the schematic. All good...

 

[jcpst]

I am curious to know from others that have already built the Duo-Phase with the extra I/O, how often do you really use the Phasor B input, and how do you actually use it?

There’s two ways I use it. One way is stereo. It’s pretty rad when the modulation is going back and forth between two amps.

The other way is in my programmable loop switcher. I can run the two sides in series or parallel. I can flip the order of them. I can put a dirt pedal or other effect between phasor A and B.

 

[moosapotamus]

For stereo output, I don't see why you would use the secondary input unless you are mixing two different instruments/inputs, one to the first phaser and a different one to the second phaser. Is that what you are doing?

Secondary input makes total sense if you want to be able to treat it like two separate phaser pedals, like you do with the loop switcher. Sounds like a cool setup. But I don't have plans to use a loop switcher, and can't think of any other ways I would use the second input. So, thinking I'll leave out the second input, but definitely include the second output for stereo. Plan to add the series/parallel switch, too. Thx!

 

[jcpst]

Is that what you are doing?

Yep- like it’s two phasers that I can choose to synchronize.

But I still split my signal and use both inputs in a stereo setup. This pedal is not true MISO. The signal going into side B is the output of side A. So output A is A, and B is really A -> B.

If you want your bi-phase to be true two channel / stereo, you need to use both inputs.

 

[moosapotamus]

Yes, both inputs in parallel for stereo, sorry. I'm locked into doing this series/parallel mod. I don't think I will ever need or use a second external input jack if I add the S/P switch. In parallel mode the input gets sent to the inputs of both phasers internally.



Also, by using a switching jack you get only A at out A, and only B at out B.

My PCB is populated. Now to wire it up and try some other mods! Thx!