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Avo CT-160 - last updated 26/08/06 21:34:52



ct160.gif (62712 bytes)Shown on the right is one of my Avo CT-160 portable valve testers.  The one in the pic is c.1962, which gives some idea of the durability and quality of these testers.

In addition to the go/no-go facilities offered by testers, this one allows measurement of anode current to be made with surprising accuracy.  It allows allows mutual conductance (gm) to be measured - this is invaluable for applications requiring matched valves.

Different heater voltages are catered for, as are different anode and screen voltage, all selected by clearly marked rotary switches.

Gas testing is available, which will give an idea of the amount of residual gas in a tube, and will allow leaky seals to be detected before a "flash" occurs.

Also checks rectifiers and signal diodes to see what kind of shape they are in.

For instructions on how to use it, click here.  David Crittle has the calibration instructions on his site - you can read them by clicking here.


Tests Filament, Insulation, cathode/heater leakage resistance to 25M ohms, gas, current draw, mutual conductance.
Bases British 4/5/7/9 pin (B4/B5/B7/B7A/B9), P type base (8SC), International Octal, Mazda Octal,  UX4, UX5, UX6, UX7, American SM7, American loctal (B8B or B8G), B9D, B8D, Hivac 4 pin (SM4), Hivac 5 pin (SM5), B7G (miniature), B9A (noval), B3G, 5AA and 7AA for Acorn valves, F8, B8A, B5A.

Two uncommitted clips which can be connected to top cap or side cap connections.

Mains Selectable 105-120 in 5V steps, 175-250 in 5V steps @ 50-500Hz. AC.
Heater 0.625, 1.25, 1.4, 2.0, 2.5, 3.0, 4.0, 4.5, 5.0, 5.7, 6.3, 7.5, 10, 11, 12.6, 13, 15, 16, 18, 20, 23, 25, 28, 30, 35, 40, 45, 48, 55, 70, 80, 117
Anode 20, 40, 60, 75, 90, 100, 150, 200, 250, 300, 400
Screen 20, 40, 60, 75, 90, 100, 125, 150, 200, 250, 300
Grid Continuously variable from 0 to -40V.
Other Measures anode current up to 100mA, gm from 0-20mA/Vm, diode/rectifier efficiency, short circuit protected.
Weight 25 lbs


ct160box.gif (21730 bytes) Oh yes, and it's portable!

If you are into other types of valve (tube) tester, check out Matts Tube Extravaganza as he has a whole page on Tube Testers.

Whilst on this subject, there is plenty of info on Hickock tube testers available too, and Hickock fans needing repair or service can always mail Hickockdoc for more details.

Need manuals?  Try Crowthorne Tubes -  They have manual copies available, scanned manuals on CD ROM, and accept PayPal.  This is a part time outfit run for enthusiasts rather than a big business - what a great find!

Also can do photocopy manuals from $15 for the CT-160 and a whole rack of other tube testers too.

avo160s.gif (11025 bytes) Show on the left is an early advertisement for these testers, kindly donated by Martin Ackroyd.

You can click on the picture to see the full size version.