What !!!    Another power supply???   Yes, I am going to review another power supply that came my way for testing this past week.   You all remember MRC, and the excellent power supplies that they make for HO gauge trains?  Well, they have a new power supply that will accommodate our large scale locomotives.   It is called the Controlmaster 20, which has a small scale/ large scale capability just like the Aristo Crest supply that I previously reviewed.
     The power pack puts out 20 volts with a max of 5 amps.   It has a hand held controller on a 15 foot cord.  This controller has momentum, speed control, brake, and direction switches.
     The unit is in a metal case painted black, with all switches and terminals at one end.  There is the on/off switch, a nudge switch which I would only use with HO locomotives doing slow speed switching, a mode switch that changes the power level from small scale to large scale.  There is also an LED which shows power going to the track, and which flashes when there is a derailment or short.  There are terminals for track power leads, 16 Volt AC terminals, and extra terminals to hook up a volt meter or ammeter.  There is also a standard modular telephone socket into which the hand held controller plugs in.
     The controls on the hand held controller give you total control of your train in one hand.  The throttle control knob regulates the speed fairly precisely, and with immediate results to any adjustment.  When the momentum feature is activated, opening the throttle meets with a gradual increase in speed until the desired speed is reached.  The brake control works for either left hand or right hand operation.  It will work with either the momentum switch turned on or off.  When activated with the momentum switch turned off, you get an immediate stop.  With the momentum switch turned on you get a gradual stop.   When the button is released, the locomotive will accelerate to the original speed.   When the momentum switch is on, the controller has an LED which illuminates to indicate what mode you are in.
     The main console in conjunction with the walkaround controller incorporates a memory circuit.  When running a train on your layout, you can disconnect the control cord, and the locomotive will continue to run.  This gives you the opportunity to plug the controller into another modular socket in a different portion of the layout and resume control of your train. 
      While not as powerful as the Aristo Crest, this is one well made power supply that will work well on smaller layouts, or to control a switcher in a yard area isolated from the main line.  As stated previously, it does put out 5 amps which should power most locomotives, and its maximum output voltage is 20 volts.  Power control is precise, and the features on the hand-held controller work as advertised.  I am seriously thinking of using one for my indoor loop around the plant shelf, and also on my work bench for testing locomotives and setting up sound systems.  I had no problem running the USA PA & PB on rollers with this unit.