Build Your Own Clone Message Board

hi all,

wondering if i could get some thoughts.

i have a byoc phase 90, and i'd like to install a mix pot for the wet and dry signals. i found the two 150k resistors between which i'll install the mix pot. my question is what kind of value that pot should be. one modded phase 45 had a 22k potentiometer specified. on kahel's chorus mod, he uses a 50k.

what do you guys think? what kind of value would work best?

thanks for your help!

Your you could just use a SPST switch to make/break the dry signal.

a switch would be fine if i just wanted to a/b phase and vibrato, but i thought that a blending of the two would be interesting for the sake of experimentation.

any explanation on why you chose the value pot you did in the diagram you posted? is it just trial and error, or is there a particular electronic reason?

The values I chose are for the sake of unity gain (keeping the ON signal the same volume as the BYPASSED signal)

My thinking behind it is that the total resistance to both the wet and dry signal is 300K ohms. THey are also divided evenly, so that makes it even easier. So if you cut the dry signal by increasing the resistance to 250k, then you want to boost the wet by decreasing the resistance to 50k.

I have not tried this mod myself. I have tried it with just the straight 250k pot. It worked, but the taper became uneven on either side towards full turn, which suggested that some sort of limiting resistors were needed on each side. It appeared that as you approached zero resistance after about 50k, the signal would boost. So a 27k - 47k resistor on each side should do the trick. You'll have to experiment with the value of the resistors.

Hello guys.

Sorry, Im kinda lost here...

The MOD is for MIX (Wet and Dry signals) or for Phase/Vibrato ?

Thanks...


BELLEZA.

Well....Some people consider the pure wet phase signal to be vibrato, but it is not true pitch vibrato like the VB-2 or vibrato mod on a chorus.

So the mod is to add a pot that cuts the dry signal and boosts the wet signal and visa versa.

Got it chief !

Thanks...

apparently phpbb stopped sending me emails when this board was updated!

keith: thanks a bunch for the info. i certainly do appreciate it. i was wondering if the gain or impedance of the circuit would be altered if no appropriate loading were used. i'll have to experiment with limiting resistors and see what happens!

belleza: i modded my small stone (no potentiometer, just eliminated the dry signal) and while it does sound cool, my vb2 clone is so entirely better that there isn't even a debate. the phase shifter mod is cool for the sake of cool sounds and such, but i won't say for a second that it even sounds a tenth as good as a real vibrato pedal.

Thanks Lightning_effects !

That's what I thought...

Lets keep the phaser as it is...

As I said, you may run into some unity gain problems, but that should be fixed once you find the right value for the limiting resistors. I didn't run into any other problems when using the plain 250k pot, so I don't see why there would be any problems now.