thehoj wrote:
For me, because the tube is not drawing full current until the heaters are warmed up, the voltage drop's through my B+ line are low at the start, and then as current draw through the power supply increases, my voltage drops increase over the chokes and resistor and then my B+ settles in at what I want after about a minute. I wouldn't be concerned about that either except for that maximum voltage rating on the plates of the 6AS7 of 250V.
Stop! It's ok.
Your amp is perfectly fine as is. First, the maximum plate voltage listed in data sheets is the "
maximum operating plate to cathode voltage at specified maximum current". Vacuum tubes are generally designed to handle around twice this voltage at zero current. This is why the maximum plate to cathode voltage on the 12AX7 is rated at 300v (Va) but the maximum B+ supply voltage is 550v (Vao). The 6AS7/6080, coincidentally, is rated at Va=250V and Vao=550v. Here is the cut out of the 1960 Phillips data sheet.
Attachment:
Screen shot 2014-02-24 at 5.04.07 PM.png
Second, the 6AS7 is, first and foremost, a voltage regulator and boost scanning tube. As such is it built "hell for stout" as they say. The peak inverse plate voltage is 1700v. The ability of the tube to stand up to much more than 550V at startup is virtually assured.
The behavior you describe is typical of most amplifiers. It is normal and will do NO damage to your tubes. They are designed for this. I strongly recommend you turn on your amp in the background and start planning your next project.