Diode on Phase 90, Question ?

[sam_801023]

I am planning to build Phase 90 using the Tonepad layout

However, I have a question about the 1N914. Does it serve as a polarity protection ?
Can I remove it and place other diodes like 1N4002 at other location ?
Or can I use both 1N914 and 1N4002 together ?

Thank You

[frequencycentral]

I've wondered this myself, as I'm trying to bias my Phase 180 just right at the monent. I didn't include the 1n914 in parallel with the zener in my build as I assumed it was for polarity protection, which isn't an issue for me. I tried adding it today with a couple of jumper croc leads, and it doesn't affect the vref voltage at all, so I would say it's just for polarity protection.

[sam_801023]

Thanks for your help
I see you put a zener there, is it for regulating the 9V power or the component needed for the phaser ?

[frequencycentral]

The 5.1 volt zener, in combination with a 10K resistor form a voltage divider which should give you a vref for the FET biasing of ~3 volts. I'm finding that the Vgs of the FETs is crucial, I'm using 2n5485s as I couldn't source any 2n5952. The FETs I'm using have a Vgs of -1.8 volts, and I'm having to raise my vref closer to 5 volts to get things running right.