|
OTL Asylum OTL, Output Transformerless Amplifier User Group. |
For Sale Ads |
Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.
Original Message
Fahrenheit or Centigrade?
Posted by Lew on February 4, 2017 at 14:55:09:
I assume you are talking in Fahrenheit. I used the temperature probe on my Fluke meter to measure the glass temperature on the type 7241 output tubes in my MA240s, which originally sported 6C33Cs. At or near the top of the one tube I measured, I got 100 degrees C. I now cannot recall whether the tubes were allowed time to reach a steady state temperature, either. The 7241 draws 7.5A filament current and idles at 400mA in my amplifiers, with plate voltage = ~130VDC; they can easily take 500ma idle current at that plate voltage.