IBANEZ PT-999 PhaseTone

You can hear this all over my recordings.  Mine was more of a grey colour than the example in this photo - and in considerably better condition!  Can't recall where or when I bought it, but it was a very early purchase - probably in the mid-1970s.

A simple analogue unit, it worked on the "Bucket Brigade" principal.  None of the sophistication of later designs: no 'sweep' or 'depth' controls - just on/off and speed.

It had a rich, deep sound in use, working well on both bass and keyboards.  Unfortunately, though, it was terribly noisy: as soon as you stopped playing, you could hear a distinct swooshing hiss.

Ibanez PT-999 PhaseTone