Retro 1956 Cyclometer VTVM – Hycon Model 615

A pretty cool, very rare piece of test equipment turned up on eBay recently: a 1956 Hycon model 615 AC/DC VTVM. This was a precursor of today’s digital, using analog servo circuitry to drive the numeric digit display.




These were a big-ticket item back in the day:$374.50 in 1956 would have been around $3,200 in today’s dollars, adjusted for inflation!

Hycon 615 ad

Cyclometer drive displays started turning up in the 1930s, and disappeared by the 1960s as direct digital read-outs (numitrons and decatrons, nixie tubes, and later VFDs and LED/LCDs) became available. They were initially used in clocks, with cyclometer meters appearing in the 1950s and lasting for about 10 years. Most turned up in even higher-end lab equipment, with cyclometer displays being quite rare on benchtop equipment.

This would be a great collector’s item, especially if you could get it running again! If the servo motor is good, it should be possible; there’s a schematic over at Hycon Model 615: Radiomuseum.

[Vintage 1956 Hycon Model 615 VTVM Vacuum Tube Voltmeter *Non Working*]


This entry was posted in Electronics, Gadgets, Test Equipment, Vintage and tagged , , , , , . Bookmark the permalink.

2 Responses to Retro 1956 Cyclometer VTVM – Hycon Model 615

  1. David DeRosier says:

    Interesting Meter. When I went to RTI now Gateway Tech. back in 1969 they had one of the first Nixy Tube VTVM that we could only use under the Teachers Supervision.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s