tubes. Hard soft medium?

[unclejam]

Wth? whats the difference between hard, medium, and soft tubes?

i ask because the Power tubes went out in a ampeg v-2 im buying/borrowing/fixing up

thanks

 

[JimmyM]

The differences are something some audiophile numbnuts invented in order to get other audiophile numbnuts to buy three sets of tubes instead of one. I ignore such nonsense when I buy tubes.

 

[Nick Kay]

I would guess that it refers to the idle current they exhibit, assuming a constant bias voltage. In that case, the "hard" tubes would have a lower idle current and they'd run cooler and cleaner. More hi-fi. The "soft" tubes would run hotter and dirtier, a little more vintage and spongy perhaps.

It's really all just marketing, though. In any case, an instrument amp worth its salt has adjustable bias or can be easily modified for it, so you can make those "hard" tubes respond like the "soft" tubes and vice-versa.

 

[johnk_10]

i always thought of it as the soft, medium, hard ratings referring to a grading system of idle current so that all the tubes under tests can be "matched" and grouped into sets. groove tubes had them from 1-10.

soft= lower plate current/lower output that breaks up earlier-good for guitar amps

medium= probably the best all around and 'normal' for the spec of the tube.

hard= higher current- higher output stays cleaner before breaking up, good for bass amps.