Who’s afraid of the DuoPhase?

giovanni

Well-known member
Me!
I’m planning to build a DuoPhase and I was wondering if there were any recommended mods (some reviews recommend 25K for the rate?) or any gotchas regarding parts choice and/or the build itself. Are there any critical components for which we need tighter tolerance or something like that? Should I test the LDRs? This is the largest build I’ve ever endeavored so I want to set myself up for success and I like to plan ahead. Any tips will be appreciated!!
 

fig

Village Idiot
I have one to build as well...so I'm just going to take notes :cool:
I see it has 13-TL072s. With that many, I'll either test them first or socket.
I'm guessing the LDRs should be within some tolerance....
2-switching regulators...I recall some speak about issues with using another variation of the TC1044 besides the -SCPA giving issues?
 

andare

Well-known member
Me too, that's a scary-ass, expensive build. I have to buy LDRs for this and the Electrovibe and was wondering about specs. All I can find is the 7532 125mW. I have the datasheet but it's all Greek to me. The build docs just say LDR...
 

Betty Wont

Well-known member
I've built a dozen of them. There is nothing special of note, and it is a pretty easy and forgiving build. Just lots of parts. It's just 2 Phasor II's on one board. I've built hundreds of Phasor II's in my life and I could populate them from memory at this point. No need to match the LDRs, and the tayda ones work just fine. It is not a finicky circuit, and uses all cheap and available parts. I use all tayda on these. I leave the trimpots at noon too. I've yet to build one that had any noticeable need to adjust. The Ldrs can lay flat on the pcb like flower petals or standing and facing. I lay mine flat. With the duo phase, light shields should be used to counter crosstalk with the optical phasers. I use 24/40 rubber septa on mine as they stretch a bit and fit perfectly. If you don't use the SCPA 1044 it will whine.
 

Betty Wont

Well-known member
Me too, that's a scary-ass, expensive build. I have to buy LDRs for this and the Electrovibe and was wondering about specs. All I can find is the 7532 125mW. I have the datasheet but it's all Greek to me. The build docs just say LDR...
This is the best ldr for the Phasor II and Duophase. I've bought thousands and never had a dud.
 

giovanni

Well-known member
Me too, that's a scary-ass, expensive build. I have to buy LDRs for this and the Electrovibe and was wondering about specs. All I can find is the 7532 125mW. I have the datasheet but it's all Greek to me. The build docs just say LDR...
IIRC, the 7532 has a wavelength of 615nm, a 6.7Mohm dark resistance and 10Kohm at 2ftc (footcandle?), 500ohms at 100ftc. The Tayda datasheet says 10-20Kohm at 10lux (~1ftc) while the dark resistance is 0.5Mohm.
So it sounds like the 7532 has a slightly wider resistance range (it probably gets around 20Kohm at 1ftc, same as the tayda one, but it gets much higher than 0.5Mohm when dark) and the fact that the wavelength is slightly lower means that it resonates better with a darker red LED (although the difference between 615 and 650 is barely noticeable, check out this calculator).
In short, the 7532 will probably work just as well would be my guess.

$150 each my friend;)
Where do you sell them? Reverb, eBay, word of mouth, all of the above or elsewhere?
 

andare

Well-known member
IIRC, the 7532 has a wavelength of 615nm, a 6.7Mohm dark resistance and 10Kohm at 2ftc (footcandle?), 500ohms at 100ftc. The Tayda datasheet says 10-20Kohm at 10lux (~1ftc) while the dark resistance is 0.5Mohm.
So it sounds like the 7532 has a slightly wider resistance range (it probably gets around 20Kohm at 1ftc, same as the tayda one, but it gets much higher than 0.5Mohm when dark) and the fact that the wavelength is slightly lower means that it resonates better with a darker red LED (although the difference between 615 and 650 is barely noticeable, check out this calculator).
In short, the 7532 will probably work just as well would be my guess.
That all went right over my head except for the last sentence. I haven't ordered from Tayda because of the shipping fees to Europe but there's no other way to get painted enclosures so I guess I'll have to eat the fees.
 
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giovanni

Well-known member
LMS also has painted enclosures but probably the same shipping fees… about the LDR: socket and see how it goes?
 

giovanni

Well-known member
94b23da4f8a6e329d85303685946d0ce.jpg
 

Diynot

Well-known member
I built one as my first “big scary board” and was still pretty nonchalant ab parts selection, unmatched Tayda LDRs with no light shield etc. Works beautifully and as Betty says, not really a complicated build, just a high parts count. I love running both in series with an offset tempo, makes a very lush vibe sound to me.
 

Betty Wont

Well-known member
What a great tune. I love those records.
The phasing part it does sound like that, yes. I hear a flanger and delay going on too. It excels at doing the Pink Floyd Dark Side phasing. It's very watery, not super intense with the feedback unless you stack them.
 
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