MIT Z-1 IMPEDANCE STABILIZER

 In very good physical condition and perfect working condition, we obtained this unit when purchasing a monster system using an AR SP 15 Flagship Preamp and two AR Classic 150's. The previous owner raved about the unit. 

From MIT

The Z-1 contains patent-pending circuitry to control Audio Frequency Distortion (AFD) and works in parallel with your audio system.  Therefore it cannot limit current or add its own distortions, as most series transformer-based "power line conditioners" do.  With the Z-1, your audio system will reproduce more, and more accurate, low-level musical details and a clearer, extended soundstage.  The greater the power-line problems, the greater the improvement you will notice in your system.  

The Z-1 was designed to work with your power amplifiers.  If your amps are on a single circuit breaker/line, you need only a single Z-1.  You may place the Z-1 on a shelf or on the floor.  It is better not to stack it on or under other components.  Do not use an extension cord on the Z-1.  Keep is as close to your audio/video equipment as possible.

The instant you plug in the Z-1, it is on and working.  There is no on/off switch.  There is no break-in period.

The A/B switch controls how much of the Z circuitry you use.  We Recommend that you begin with the A position, because most listening reports indicate that this gives the optimum results.  However, we urge you to try the B position also, which is intended to handle extreme problems on the power line.