Duo Phase weaker B side

Matopotato

Matopotato

Active member
I just finished setting up a Duo-Phase build. I did the instructions from third post and link in second here, and that seems to work.

20250106_124447.jpg

I put the trimmers on pots for external control and add shields @Chuck D. Bones style.
But I still feel the Blue side/first side/B-side/right from knob view/left from gut shot sounds a bit weaker. It dose not phase as much. The Amber/A-side is what I was hoping for.
The only visual difference is that the LED on B-side seems a bit more dimmed, and the LED on A-side more clear. It is hard to show in pictures and bring justice to the differences. In the A-side one you can see the source as a center brighter spot, but on B-side it is dimmed so that does not show.

Could the difference in LED brightness be a reason the sides sound so different, or is the B-side supposed to be quite a bit "mellower" in its phase-sound?

LEDs on:
20250106_124713.jpg

LEDs off:
20250106_125740.jpg
 
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ok I come here because I have the same problem (even if the sound is good I don't think this brightness is normal, the effect could be more intense). Have you identified the resistance that determines the intensity of the LED ?
 
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Since it is the B side that is the weaker one, I felt when set to B (and they are independent) Innotice the difference, when set to A I felt A way of sounding sort of took over.
Reverse I could not tell much changed at initial trying things out so did not experiment with it either. I thought it was more about phase shift?
 
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Robert said:
Does it make a difference if you invert or sync to the other LFO?
Click to expand...
No, I would say the switches do their things: When set to A, the rate of B changes to the one of A, but sounds as weak still. Invert I can tell something happens, but no change to the strength of B.

EDIT: I can't see any differences in the section around the LEDs, so it does not seem to be any built in feature.
I will try to hunt down a yellow LED with a bright center, not a fully clear one, that it is probably too much. But the dimmed one seems to make the phaser on that side too weak. That said, A-side is not like a crazy all-over-the-place phaser, but I was not expecting (nor hoping) for that either
 
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I finally managed to get a more intense yellow LED. Swapping it out worked fine. I thought. Until I plugged it in to test it and strange sounds and smoke began coming out of the box. After some investigation I noticed I had forgotten to cut the legs of the LED and thus fried the 2N4401 transistor. That smell stays on for quite a while. It seems the TL072 made it through, and it is only supplying base current so it should have been that much in harm's way.
Tried out 2N3904 and 2N2222A and thought the 2N3904 sounded better of the two, but I am more likely fooling myself here.

It now works better in that the B-side has slightly more phasering going on, but it is still a bit weaker. So I put that down to being part of the circuit.
I can get both sides to phase into each other, but the overall feeling is that it is more to the subtler side than the "in-your-face-phase" I was hoping for with some more aggressive settings. I could still have made errors that makes it what it is at the moment, but it sounds nice for what it is IMHO.
 
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