Phase 90 R28 resistor?

[Danny G]

I did the R28 mod to my Phase 90 and it sounds ok.  I'm thinking about re0installing it with a mini-toggle switch, but threw away the resistor after I had destroyed it!

What is the value of R28?!?


Thanks!

[Fret Wire]

R28 is 24k...that mod helps the newer ones alot. They're almost usless for acoustics or keyboards when stock. I also remove the pre and de- emphasis caps, and lower output to unity gain. Really mellows out the boost and strong mid-hump. One thing you'll notice on the Dunlop reissues, is that it is easier to clip out components than to desolder them. Plated-through, oversized holes make it a pain to desolder cleanly.

[Danny G]

Pre- and de-emphasis caps...  please explain, since I have become mod-crazy in the past two weeks 8D!

[Fret Wire]

When you pulled R28, you diminished the regeneration, and cut the midrange response, sounding more like a script logo Phase 90. That was the most important mod, losing the distorted mid-boost.

Removing the pre & de-emphasis caps will give a slightly higher noise floor, and raise the headroom about +3db @ 1.3Khz & +12db @ 7.2Khz. That, and lowering the output to unity gain mellows the effect more, to where it does not color your tone any more. Really noticeable, if all you're used to is the late MXR/Dunlop reissues. Brings it slightly past the script sound towards phase 45 mellowness. Now it's totally useable with acoustics and keyboards. It'll still phase, and sound good with distortion, and won't color the amp's sound. And if you put it after your OD/Dist. pedals, you'll still get that over the top phasing sound.