Phase 90 cloneis too speedy!

[hamedbb]

hi there, i build a phase 90 from tonepad. i used three kind of JFETs and but I still have a minor problem. the speed is too high. it doesn't matter which kind o FET i use, the speed is too high. and one thing, if i use a 15uF cap as it is in original circuit, i don't get any phase except in the highest speed! but i use 4.7- 6uF cap and it works but still the speed is too high even in the minimum rate. what do you think the problem is? and what about if i want to add depth  pot? what exactly Depth knob do in phase sound?

[Mark Hammer]

The speed depends on the capacitor you mention.  Making the value smaller/lower than 15uf will make the range of speeds faster.

But the range of speeds will ALSO depend on the value of the Speed pot and the 4k7 resistor in series with it.  The pot should be 500k, and should be a "C" (reverse-log) taper to have a smooth increase in speed as you turn to the right.  If this is hard to find where you are, you can use a log (A-taper) pot but wire it up so that speed gets slower as you turn to the right.

The 4k7 resistor sets the fastest speed.  If you want to change what the fastest speed is, you can replace that resistor with a 3k9 in series with a 5k-10k trimpot, and adjust it to suit your preference.