The 1955 Heathkit 500V PS-3 power supply

New York engineer Reginald Neale recently sent pictures of his antique and unusual electronic collection. So I figured it would be a great idea to feature one of his interesting gizmos for our #ThrowbackThursday blog.

Here is Reginald’s Heathkit PS-3 500-Volt power supply. Neale notes, “Heathkit. The Big Name in build-it-yourself electronics. I built this one in the late 1950’s.” After getting this image from Reg, I found a scan of the spec page on the internet, and used the fantastic ABBYY FineReader OCR (optical character recognition) to change it into text:

                  SPECIFICATIONS
Output............................Continuously variable from 0-500 volts, 
                                   no load
Regulation, Line Voltage 117 volts AC: Linear 0-10 MA at 450 volts output < 0.5%
                                              0-20 MA at 400
                                              0-40 MA at 350
                                              0-70 MA at 300
                                             0-100 MA at 250
                                             0-130 MA at 200
Line Variation 105-120 volts..........Output variation less than ±2.0%
Meter.................................4 1/2" streamlined case
      Sensitivity.....................1 MA full scale
      Range...........................0-500 volts DC, 0-200 MA DC
Tubes.................................1 - 5V4G Rectifier
                                      1 - 6X5GT Rectifier
                                      2 - OA2 Regulator tubes
                                      2 - 1619 Control tubes
                                      1 - 6SJ7 Control Amplifier
Power Requirements....................105-125 volts 50/60 cycles AC 90 watts
Dimensions............................8 1/2" high x 13" wide x 7" deep
Shipping Weight.......................17 lbs.

Neale points out: “Heathkit was famous for their easy-to-follow manuals and large, detailed pictorial instructions.”

There was a nice schematic on the Sal’s Antique Radios site. Note how the unit makes 6.3V to power the filaments of any tubes you have in your circuit, as well as the high-voltage output.

The Old Tube Radio Archives had this nice interior shot.

The same site had this shot of under the chassis.

The RadioMuseum site has a page on the PS-3 as well. It a heck of supply, putting out 500 Volts, enough to bias up tube circuits. Be sure to read up on how my mentor Bob Pease made a low-noise 300V supply. Both Reginald and Bob go back to the day when your lab supply could kill you.

Here is an ad from 1955 that Reginald scanned for your enjoyment (1.2MB pdf). Heathkit-ad_1955