The Doepfer A-125 is a simple All Pass filter, - ie the core of a "phaser" effect, just add an LFO to create a phaser!

The A-125 features level control, wet dry control, resonance (which changes the color and depth of the comb filtering), and shift/cutoff control (the thing that moves in a phaser).  More than just a phaser, try CV sources other than LFOs to create interesting effects or try filter pinging effects by feeding short triggers into the audio input with somewhat high resonance to create interesting analog drum sounds!

Specifications:

8HP

65mm Depth

20mA @+12v

10mA @ -12v