Bi-Phase Options

[reggaebass]

Hi All,

I'm still a novice builder (I know this advanced territory), I really want a Mu-Tron Bi-Phase for an outboard dub effect.  I'm not sure I want to save up 1.5-2k for an original.  I'm guessing some of you are familiar with the Jeff Rubin Electronics Mutant Fly-Phase?  Not sure why the LDRs are bent different directions in the attachment?  Has anyone built the Lola Phase from Dead End or maybe there is an archived Madbean project that is close?  Any input is appreciated.  Thanks! -Craig

[jubal81]

Looks like those are built on PedalPCB Duo-phase boards. You can find it here

[jimilee]

^^^^awesome boards. I'd course, I had to build one!


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[WormBoy]

Not sure why the LDRs are bent different directions in the attachment?

Hmm, each unit seems to follow a different strategy: LDRs facing the LED, LDRs facing up, and LDR kinda random wobbled ... Maybe the inside of the lid will reflect the light? This indeed looks exactly like the PedalPCB board, so you can build one yourself if you're patient enough. What I wonder about this board/build is why there is no light shield. I would imagine that the LDRs around LED A would be affected by the light of LED B, and vice versa, when they are not perfectly in sync. The original units had LDRs and LEDs in encapsulated form, as far as I can tell from the internet.

[PMowdes2]

I might be biased but the deadendfx Lola is as close to the original as we could get it.  The power supply is modified and the input for the pedal has been modified since the original opto pedal is near impossible to recreate.

I think the pedal PCB version is based on the mutron reissue, which isn't the same as the original unit, I might be wrong but the reissue is just two mutron phasers in one box, it doesn't have the same waveshaping options as the original

[Betty Wont]

The Lola is great sounding, and behaves like the Bi-phase should. The Pedalpcb duo phase is just two "neutron" phasers stuck together with an inversion/sync thingy between them. It is a nice project, but not exactly a bi-phase. The Ldr's on those example pictures are all wonky and unshielded, makes me wonder if the builder understands what is going on there.

[digi2t]

Not sure why the LDRs are bent different directions in the attachment? 

Looking closely, it looks as if the unit to the left is using different LDR's than the other units to the right. The random bending of the LDR's is probably an attempt to normalize the resistances versus luminosity. In my book, a quick and dirty, but poor method of part selection and execution. For the Lola, we specifically remark that LDR, LED, and driver transistor matching be done for the Lola build. While that means having to sort through and reject many parts, it's the price you have to pay to get the best performance.

And yes... in the case of the Mutron or Lola, light leakage from one set of LED/LDR's to the other will definitely affect overall performance. This is why the original, as well as the Lola, use shields. Otherwise, especially in series mode (in A, out A to in B, out B) you'll never really get that wonderful, swirling "two phasers running at different speeds phychoacoustic effect" that makes the Bi-Phase (or Lola) magical.

[Aentons]

...in series mode (in A, out A to in B, out B) you'll never really get that wonderful, swirling "two phasers running at different speeds phychoacoustic effect" that makes the Bi-Phase (or Lola) magical.

Please forgive my ignorance and/or oversight... It seems like you are essentially describing what you could do with almost any two separate phasers in series. Also, I thought part of the magic in the bi-phase was the parallel mode(out A) and/or the reverse sweep sync.


Edit: sorry, I think I misread your statement. You were saying that the parallel mode(out A) is part of what makes it special. (which I agree)

As a poor mans version, I run two "regular" phasers in combination with a Boss LS-2 line selector. It essentially gives me the same switching options as the bi-phase plus a coulpe of extra. You could put the 3 components all in the same box if you are not too picky about having all the vintage correct options. I don't really care about the square wave, lfo sync, or expression control, so it works for me.

The Duo-phase (i think) is only series, but you could prob fit a series parallel switch/board in the enclosure if you wanted.. or just get the Lola


Edit2: On second glance, in the screenshot of the Jeff Rubin Electronics Mutant Fly-Phase, it looks like he has a series/parallel switch wired up in the top middle. It appears to just be passive split, not sure if it is active or passive in a real bi-phase. Also, It doesnt appear that the bi-phase has any sort of output mixing, so I think if you want stereo output, it goes to two different amps(or mixer channels)

[reggaebass]

that wonderful, swirling "two phasers running at different speeds phychoacoustic effect" that makes the Bi-Phase (or Lola) magical.

@digi2t - that is definitely what I want.  I have been going over the Lola build doc for the last week and I really want to build one but I have only built ODs and Fuzzes so far.  I feel like giving it a shot and just taking my time and being careful.  Thank you to all of the PCB makers and builders, I have been lurking for a long time, this is a great community. 

For digi2t for anyone that has built a Lola, any recommendations for 2 channel oscilloscopes?

[digi2t]

For digi2t for anyone that has built a Lola, any recommendations for 2 channel oscilloscopes?

I use a Hantek DSO-2090. The screenshots in the Lola build document are taken from the DSO application.

[reggaebass]

Thanks digi2t.  I just ordered a Lola, why not try one of the hardest projects as one of my first pedals

I'm just going to be slow and methodical and pay a lot of attention to your doc.  We'll see how it goes!

[digi2t]

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