phase 90 mods

[tubescreamer1010]

i got a phase 90 and im happy with it accept for one thing when i strum hard and the pickup is  at full volume the effect breaks up and sounds terrible if anyone knows how to fix that and has other mods that would be awesome

[petemoore]

  Not sure if your'e exceeding the headroom with strong input, I thought the PHase 90 was supposed to be tolerant of high inputs levels...but I don't know that.
  Compressor in front?..Higher supply voltage?..input gain control?..
  I would take voltage measurements of the opamp pins first.
 

[Mark Hammer]

The Phase 90 provides no built-in opportunity for attenuating the input signal and bolstering the output in complementary fashion.  You could probably boost the input and attenuate the output but that's the opposite of what you want.

Unfortunately, FETs are limited in their headroom, which is one of the reasons why LDR-based phasers are generally preferred.  There ARE some things you can do to improve the headroom of the FETs, but that would be cumbersome in an already-built unit.  It would seem that your primary choice is to simply reduce the level of whatever you are feeding the phaser with.

As an aside, let me point out that while I think buffers and preamps built into guitars are not "bad" things, this clash between FETs and too-hot guitar outputs is a perennial problem that refuses to go away.  It was a dilemma in the late 1970's (see my article in DEVICE  http://hammer.ampage.org/files/Device1-12.PDF ) and still hasn't changed.  "Hot" guitar outputs can be a great thing if there is nothing between your guitar and amp, but the moment pedals start to enter the picture, things like overwound pickups and on-board boosters start to complicate matters unless you plan out your signal chain very carefully.  Not everything is comfortable with a hot input signal (as your P90 illustrates), and you always need some way to conveniently trim back on level to accommodate those pedals...or else switch pedals.