Dr Phybes no effect

[Anonymous]

Hi all! So I’ve just completed 2 Dr Phybes builds and I’m getting no effect from either. Pedal passes a clean signal. I’m getting a variable voltage reading at the pot and pin 6 of IC3. I can follow it along and it seems to stop at R23. Variable reading on one side of the resistor and constant on the other. None of the transistors are getting a variable reading. Trim pot has no effect. Any help is greatly appreciated.

Thanks!

[Cybercow]

Have you tried adjusting the trimpot on the board? There is a very small “sweet spot” at which it will render the phase effect. Turn it VERY SLOWLY or in tiny increments to find that “sweet spot”.

If that doesn’t do it, we’re going to need some good clear photos of both sides of the build and all the wiring connections. It would good to know that you’ve measured the voltage supply and are using the correct voltage.

[Anonymous]

Thanks for the reply, the trim pot doesn’t seem to do much or if it is it’s very subtle. Here’s some photos of the build. Thanks again!

[Billy]

What type of transistors are you using are they matched 2N5952 from Barry

[Anonymous]

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Negative, they are 2N5459

[Cybercow]

Josh – 2N5459 will not work. The Dr Phybes build requires a “matched set” of 2N5952 FETs. Also, the pinouts of 2N5459 are reversed from those on the 2N5952.

[Anonymous]

Ah, that was sort of my suspicion. Thanks for the info!

[Billy]

Josh you’re better just getting a quad set from Barry they’re on sale at the moment at a very reasonable 14.95

Saves all the hassle of going through 100s to try and get a matched set and 5952s are pretty expensive nowadays

Where are you located

[Author]

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