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floobydust wrote:

Paul, I suppose that new vs old between the 45 and RE604 could account for some differences, but it's more of an "apples to oranges" comparison. Pushing the 45 beyond it's ratings is not a great idea... especially the cathode current as it will certainly shorten it's life... I always run the 45 around 34-36ma and never any more. You can run the plate a bit beyond 10-watts (the final revised rating) provided you have adequate airflow and keep the cathode current down.

I have a question. I have a situation in here that needed a minor correction. It might be left as is but still I would like to fix it. Sine I have my hard is set not at 45 tube I would like them to run very much equal. My amps not have rig and left channel run ~5mA different. With the same tube the left amp has (K-G-A) 191V-155V-407V and the right amp has 198V-161V-407V. That makes left amp to have 5mA less currant then right and I would like to make them the same (with the same tube). I can match the DC that comes from driver tube (155V vs. 161V) but the voltage drop on my cathode is different, probably due to the not exact value of the power resistor.

So, I probably will not remount it but will put a large resistor in parallel to the higher one and will make the cathode resistors the same. My question is: how much you advise to drive my 45. Usually people think how to get more power but I do not need power. So, I do not have the “best” operation point that would assure the most power but I rather can driver it wherever I wish. So, how much shell I wish?

The 45 is 10W tube. I have 407V-191V or 208V on the tube and I run it at 35mA and 40mA or at 7.5W and 8.3W. Where do you fee; it the good point to me settle: 35mA and 40mA? Sonically I hear no deference…

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