Cool new valve tester from Orange

[jpfamps]

This has just come to my attention:

http://www.orangeamps.com/products/accessories/amplifier-management/vt1000/

Looks a very useful and easy to use tool.

[FELINEGUITARS]

I really want one for all the valves I have in preamp modules ...and I thought it would be cool to offer to test valves for customers too.

I kind of wish that it had a computer interface and would produce a detailed report of the results of each test, but I also like it's simplicity

Frank - based on the results it might show for 3 different preamp tubes how would you decide to put in which location in an amp - say a Marshall 50w plexi ??

Highest score first (assuming highest gain factor) - Most balanced/matched pair of triodes as Phase inverter  and the other as 2nd stage?

[Dmoney]

I agree about the computer interface.

In my experience preamp valves tend to work or they don't. meaning they just don't work at all or they are microphonic or that they are sensitive to 50Hz hum induced by the filament supply. That tester won't tell you about the hum or microphony which are probably the main factors in rejecting preamp tubes most people have lying around. Easier to test for those by putting them in an amp. If you swap a valve and you get no sound or something then there is going to be a more substantial fault, like a triode (or both) is dead. So for me, in some ways its easier to test preamp valves by sticking them in an amp and listening to what they do.

The balanced triode thing is a tool used to sell 'matched triode' preamp tubes. It's not needed at all. In fact, in about 95% of amps using a long tail pair inverter the circuit is usually set up like that of the marshall PI. It already takes into account a lack of balance by biasing each triode differently. Usually by using a 100K plate resistor on one side and 82K on the other. You can use other values to get a better balance or even wire in a balance pot to get it exact... but then you have the argument that having a slightly unbalanced PI might give you something pleasing in the way of tone.

Amplifiers using other types of PI can be inherently balanced. Such as when using a Cathodyne which uses one triode to get both phases to feed the output valves and the other triode usually as a gain stage to drive it. In that situation balanced triodes gives no advantage at all.

[jpfamps]

It would be nice to have the computer interface, and from what I understand this could be done, but it will depend on whether the manufacturer wants to release the software.

re pre-amp valve testing, I'm with Dmoney on this; I'm not sure how any results would inform you of where to employ pre-amp valves for optimum performance, although it's possible that once you have accumulated enough data of your own you may come up with some useful patterns.

Don't know if the unit tests for noise.

Microphonics is a major issue with pre-amp valves.

I usually test pre-amp valves in an amp.

[ridner]

when is this supposed to come out?