PRRI Tungsol bias Question

[steve from mo.]

I have a PRRI that I have done the OT upgrade and have put in a set of jj 6v6 tubes. The origional GT or Electro Harmonix 6v6 tubes were biased at 22ma so I biased the JJ 6v6's there as well. I usually play clean and am happy with the tone of the amp except when it is dirty It sounds brittle. I seem to play at a vol. that is on the verge of clean and dirty. I have heard good comments on the tungsol tubes so I thought I would give them a shot hoping that if I did play loud enough that maybe it wouldn't be as brittle.

All this and now my question. When I ordered the tubes I asked if they had a bias recommendation and they said it would be on the tube.

My receipt says bias point 1.0 What does that mean? and my Tubes say bias point 33 What does that mean?
any help is greatly appreciated steve

[Scott S]

The PRRI's stock bias is 23mA per tube, which is not as cold as you might think, considering the plate voltage of 440V(!) JJ's can handle a lot of dissipation, but I'd check the plate voltage in your amp before going too crazy with the bias.

(I'm not sure what the "bias point" numbers mean, either...)

- Scott

[jefrs]

Imo the JJ 6V6GTS is a 5881 with a smaller heater current and they can run very hot indeed. I've used them in place of 6L6GC with no problems, very loud, very clean, not brittle. I expected less headroom, they stayed clean. Probably one of the best 6V6 types. Perhaps it's your JJs that want re-biasing. On the other hand you may need a proper 6V6.

[Stan Martin]

to 28mA, if it does start to red plate back off the bias a wee bit. btw- I don't know how faithful the reissue is, so you may not have a bias pot in there. If you don't have a pot consider adding one.