Elrog 300B vs Takatsuki 300B tubes

Today, over a six hour period, I measured voltages ranging from a low of 122.1 to a high of 123.3 on the dedicated lines in my listening room. My most current measurement was 123.2. I have a total of 5 dedicated duplex outlets feeding my listening room and the voltage measurements have been identical at each outlet. I also measured for stray voltage on ground and that tested at zero for each outlet. My utility company will not do anything to help me because my voltage is within 5% of 120 volts.

I own the Frankensteins and Takatsuki, Elrog, Sophia Royal Princess and Black Treasure 300B tubes.

I don't pretend to have the technical knowledge to participate in this conversation, but am I correct that I should not be using my Takatsuki tubes in the Frankensteins given my high voltage readings?

Hello,

Thanks to snopro for his efforts on this topic...I received the results a day earlier ;-)

By my oppinion a variac is not needed. As can be seen all the measured tubes are having a little bit different operating conditions. All they are 300B fitting the WE300B datasheet (more or less) wthin the tolerances...The Takasuki's running a little "hotter" and the Psvanes a little "cooler". This is the effect of the deviations of real tube data...(against the design center values/plate curves in datasheet)
So the task is very simple. We have to select the "right" pairs of ER300B fitting to the operating conditions of the Franks (or any other amp whose conditions are known) in all cases(+10% or -10% main voltage) with a small safty margin.
A smart dealer like Gorge should be able to affairs which.
No variac is needed nor any changes in the amp...We only need to know the type of amplifier, so we can deliver the fitting tubes. (This way will improve the sound quality too.)

Regards, Matthias

Matthias,
Thank you for that encouraging and reassuring post. I patiently and eagerly await receiving my replacement Elrog tubes from George. I believe this thread and your contributions have been helpful to quite a few here.
Charles,

Mathaias, my Elrog 300B tubes are still functioning properly, but have only about one month of warranty left. Will Elrog accept a return on my tubes and send me a pair suitable for my Coincident Frankenstein amps?

You gotta love people who are dedicated to providing quality service. Tube matching to your particular amplifier! Awesome! Gotta love it. Well done, Matthias. Now I have to figure out how to get the operating parameters for my LadyDay+ amps.