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EICO 625 Vacuum Tube (Valve) Tester

EICO 625 Vacuum Tube (Valve) Tester

The EICO 625 is a very early and quite common tube tester which has long since been discontinued. In 1958 the EICO Model 625 listed for $34.95US which is roughly equivalent to about $288 in 2014. You sould be able to find working conditioned EICO 625 tube testers for under $100US. The EICO mODEL 625 is an emission tube tester which gives you a basic idea of what condition the vacuum tube is in. One thing to note is that the EICO 625 test will not measure transconductance, so this style of tube tester cannot be used to "match" vacuum tubes. For tube matching you will need a tube tester that can measure dynamic conductance, like the EICO Model 667 tube tester. The EICO 625 tube tester has many different tube sockets including ones for 4 and 5-pin tubes.

EICO 625 Vacuum Tube (Valve) Tester

Photograph 1: EICO 625 Vacuum Tube (Valve) Tester

Inside the EICO 625 tube testers there is a vacuum tube under the panel. The lone 6H6 diode is used to rectify one of the AC filament voltage for the neon indicator bulb used for identify "Tube Short". The EICO Model 625 tester was later updated to accommodate the newer tubes being developed during the 1950s - the updated model was called the EICO Model 628 Tube Tester.

EICO 625 Vacuum Tube Tester - Inside View

Photograph 2: Inside View - EICO 625 Vacuum Tube (Valve) Tester

Instructions Manual and Tube Data Chart - EICO 625 Tube Tester

The instructions manual is from the BAMA web site. Check out their archives for more hard to find tube manuals.