Power Lab 711 (711K, 711W)

The Precise Power Lab 711 combines a variable high current low voltage power supply with an isolation transfomer that can be used independently or can be switch-connected as series-aiding or bucking for a variable isolated supply up to 3 amps AC for 90-140 volts, which can in turn be selected as rectified and filtered from 110-180 VDC at 75 mA continuous. 

Variable low voltage at high current is available as AC from 0-24 volts up to 20 amperes or DC from 0-15 or 0-30 Volts at 10 amps continuous. 

The high current low voltage variable AC can also be switched to boost or buck line voltage directly from 90-140 VAC up to 10 amps continous but without isolation.  The 711 was available as either 711K (kit version) at $49.95 or 711W (wired version) at $64.95.  The 711 isolation transformer was rated at 100 watts.  A model 713 was also available at higher cost but increased isolation transformer output to 300 watts.  

Here you find 46 models, 45 with images and 14 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Precise Development Corp.; Oceanside, Mineola, NY