Mu-Tron (MuTron) Phasor II 1974-1975 Refurbished

1973-1974 Serial Number 1005 Musictronics MuTron (Mu-Tron) Phasor II.   This is a refurbished unit (see below) but it works as well as the original kit.  Amazing, deep swirly tones, with a feedback, rate and depth control to a create wide range of tones.  Think of Chris Squire's bass in the Yes "Drama" era, Rick Wakeman, Jimmy Page on "No Quarter" and countless other classic rock and prog songs defined by that slightly twangy, slightly ringing, signature tone of the MuTron.  It has six stages of phasing, very low noise and the feedback/sweep are nice even at very low rates.  This was a keyboard player favorite due to its ability to handle high output instruments, and the AC power means you aren't current limited or suffering signal quality when you really drive it.

Plugged this in with both guitar and bass and ran it through the range of settings and frequencies; it sounds as good as the 45 year old original unit. I've been on a serious vintage Yes kick and am tempted to keep this unless it finds a good studio home.

I bought this as a non-functioning unit -- the AC power transformer had literally melted (it happens; they are mechanical windings and years of hard use, vibration and lots of current can cause physical deformation of the coils).   Cleaned up the board, installed new transformer with identical voltage and current/amperage specs (thanks to the MuTron vintage community), rewired the output and input jacks and cleaned up the footswitch wiring.  Had to replace two of the pot nuts as they were corroded badly, but everything else is original.  You can see the original and replacement power sections in the pictures.

NOTE: the new transformer is about 1/16" of an inch taller than the original, so the case does not close perfectly.  I didn't want to force it and bend the main circuit board, but you can try adjusting the lower pot nut depth and use the standoff/screw combination to "pull" the board.