Tube hardness breakup ratings?

[jaimz]

K so I have been looking around at power tubes and I am seeing the option for hardness ratings from early breakup to late breakup when you order. Does this apply to any amp or is it only for fixed bias amps and hifi stuff?

[cmr415]

If your tali9king about Groove Tubes, I think it applies to all amps. Not sure how "accurate" GT's power hardness rating is, some have said its more hype than anything

[Blue Strat]

It mostly applies to fixed bias amps.

Note that GT power tubes that fall outside the 4-7 ratings are the ones that have most problems.

[jaimz]

Originally Posted by cmr415

If your tali9king about Groove Tubes, I think it applies to all amps. Not sure how "accurate" GT's power hardness rating is, some have said its more hype than anything

Ya I saw it on groove tubes. But I orignally started down this path while looking to buy a quad of EL34 SED winged cs. One of the sites I was looking at had a drop down to choose from for SEDs with the hardness options (early or late breakup). Hadnt heard about this before.

[solitaire]

Somehow GT have managed to screen valves that distort in relation with their current draw. Obviously the early breakup ones will compress more than the later ones.

You will basically achieve the same effect by running your power-section on full throttle and keeping your pre-section low, beit with a slight possible loss of tone.

As for the GT rating, you can get in touch with Myles Rose and he might be able to explain it to you properly.