Symetrix 606 delay and fx machine / rack unit

Up for sale is a Symetrix 606 delay and effects rack unit. This is a famed delay machine, but it can do much more than that. If you are viewing this, then you are probably aware of its capabilities.

I have used this unit almost none since I bought it a couple of years ago, and so I am not all that familiar with the details of the unit. I tested this by playing a guitar into both inputs and cycling through presets while monitoring the outputs for reasonable results. I didn't notice anything out of the ordinary, but this is the most testing I am able to do. The unit is quite deep in terms of programming, so knowing the unit is working 100% as expected would require one to be very familiar with the settings of a particular preset and the machine in general. I do not have this familiarity.

Included with the working unit is a second, non-working unit. It turns on but the knobs are all wonky and don't do what you want.