phase 90 schematic help, please

[wampcat1]

http://www.geofex.com/FX_images/p180.gif is the schem I'm looking at. I've done the mod on the pedal before, but where are the parts on this schem that need changed for the 'script mod'?

Any help appreciated!

Thanks,
Brian

[Mark Hammer]

I do believe that would be the 22k resistor sitting just under the comma separating the 90 and 180.  That sets the amount of feedback/regen from the last phase-shift stage back to the 1st stage (although shouldn't that be the 2nd stage?).

[vanhansen]

If you have one of the newer reissues, then it is R28, a 24K resistor.  Go to my site (link below in my sig) and it's in the DIY Effects and Mods section.  I have picture of a reissue that shows exactly where that resistor sits.  Just clip it out.

[cd]

Does anyone else find it ironic that a commercial builder/modder is looking for help here?  At least sign in under another account, or use the search feature!

[wampcat1]

I do believe that would be the 22k resistor sitting just under the comma separating the 90 and 180.  That sets the amount of feedback/regen from the last phase-shift stage back to the 1st stage (although shouldn't that be the 2nd stage?).

thanks so much, Mark-- much appreciated!

Do you recall if the dano pepperoni phaser is the same circuit? I know it seems like a waste of time, but it's my 'side' project. (for myself), and I was going to practice some tweaks on the smd stuff with it.

Thanks,
Brian

[wampcat1]

Does anyone else find it ironic that a commercial builder/modder is looking for help here?  At least sign in under another account, or use the search feature!

:lol: no thanks -- I have nothing to hide!! I'll be the first one to tell you I don't know everything, and not near as much as some of the folks here.

[wampcat1]

Does anyone else find it ironic that a commercial builder/modder is looking for help here?  At least sign in under another account, or use the search feature!

[Fret Wire]

Brian, are you talking about the reissues? If so, R28 on Erik's site is the feed-back resistor. Removing C11 and C12 will mellow out the effect even more, almost "phase 70". Real sweet for clean tones or acoustics. You could socket them and try it with/without the cap mod.  Either way, I'd double check the trimpot calibration after. I've found they don't bother to get it real close at the factory. BTW, R7 (150k) controls the output volume. After the full mods, around 130k gets unity gain. You could make it an internal trimmer, or a small mini pot on the outside so the user could adjust for unity gain no matter where the P-90 is in the chain, or what type of pedal is before or after it.


On the Tonepad schematic, it is the 22k in red. That schematic puts it's function in perspective pretty well, so you could find it by trace, and not by number or pic.
http://www.tonepad.com/getFile.asp?id=42

[wampcat1]

Brian, are you talking about the reissues? If so, R28 on Erik's site is the feed-back resistor. Removing C11 and C12 will mellow out the effect even more, almost "phase 70". Real sweet for clean tones or acoustics. You could socket them and try it with/without the cap mod.  Either way, I'd double check the trimpot calibration after. I've found they don't bother to get it real close at the factory. BTW, R7 (150k) controls the output volume. After the full mods, around 130k gets unity gain. You could make it an internal trimmer, or a small mini pot on the outside so the user could adjust for unity gain no matter where the P-90 is in the chain, or what type of pedal is before or after it.


On the Tonepad schematic, it is the 22k in red. That schematic puts it's function in perspective pretty well, so you could find it by trace, and not by number or pic.
http://www.tonepad.com/getFile.asp?id=42

Thanks guys!
I'm actually wanting to do this mod to my little itty bitty dano  rice a roni (pepperoni) phaser. I know...I'm asking for trouble!! hehe!!  :lol:
I just wanted to make sure it would work on the dano, but I wasn't for sure what to change.