6bx7gt envelope temperature

coyotesgator · 11th December 2007, 06:34 AM

Hello everyone!
I'm sure I just missed it somehow, but I can't find the maximum allowable envelope temperature for a 6bx7gt. Is 355F OK?
Thanks in advance,
Rob

Colt45 · 11th December 2007, 06:56 AM

Sure why not.

As long as dissipation isn't much over ratings, and ambient is a human survivable environment, it shouldn't matter... Which is probably why it isn't mentioned in the datasheet.

SY · 11th December 2007, 11:38 AM

That seems pretty high. Most tubes are rated for 200 degrees C max envelope temp. You're somewhat above that- is the tube well-ventilated? Power ratings assume that the tube isn't stuck in the middle of a lot of other warm stuff and has free flow of air. If that's not the case, even run within power ratings, the tube can destruct.

Get some air on that puppy before it bakes to death.

tubelab.com · 11th December 2007, 01:00 PM

355 degrees F is 180 degrees C hot, but not out of line.

SY · 11th December 2007, 01:48 PM

My bad on the calculation, sorry.

plovati · 11th December 2007, 04:04 PM

I done a SE simple 6BX7 amplifier.
I tested lot of brands like GE, Sylvania, Amperex, Rayteon etc and all the tube get really hot in operation, also within the dissipation limits that is 13W for the sum of two section (not 10W each section if both section are used).

The hottest part is the plastic socket, and can lead to early degradation of the socket itself, a good ventilation will not be a bad idea.

Electraprint use this tube in overdissipation, ( http://www.electra-print.com/docs/6bx7se0001.pdf ) but I was told that this tube is really a robust one.

coyotesgator · 11th December 2007, 11:48 PM

I appreciate all of the replies. Thank you to all. As the other octals around it aren't really very hot, and the base is considerably cooler, I'm probably alright. Besides, I kind of enjoy the little room heater.
Rob

11th December 2007, 06:34 AM	#1
coyotesgator diyAudio Member Join Date: Sep 2007	6bx7gt envelope temperature Hello everyone! I'm sure I just missed it somehow, but I can't find the maximum allowable envelope temperature for a 6bx7gt. Is 355F OK? Thanks in advance, Rob

11th December 2007, 11:38 AM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	That seems pretty high. Most tubes are rated for 200 degrees C max envelope temp. You're somewhat above that- is the tube well-ventilated? Power ratings assume that the tube isn't stuck in the middle of a lot of other warm stuff and has free flow of air. If that's not the case, even run within power ratings, the tube can destruct. Get some air on that puppy before it bakes to death. __________________ If there's a sucker born every minute, where do the rest of them come from?

11th December 2007, 01:00 PM	#4
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	355 degrees F is 180 degrees C hot, but not out of line. __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

11th December 2007, 01:48 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	My bad on the calculation, sorry. __________________ If there's a sucker born every minute, where do the rest of them come from?

11th December 2007, 04:04 PM	#6
plovati diyAudio Member Join Date: Mar 2005 Location: near Milan	6BX7 is hot! I done a SE simple 6BX7 amplifier. I tested lot of brands like GE, Sylvania, Amperex, Rayteon etc and all the tube get really hot in operation, also within the dissipation limits that is 13W for the sum of two section (not 10W each section if both section are used). The hottest part is the plastic socket, and can lead to early degradation of the socket itself, a good ventilation will not be a bad idea. Electraprint use this tube in overdissipation, ( http://www.electra-print.com/docs/6bx7se0001.pdf ) but I was told that this tube is really a robust one. __________________ Piergiorgio


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11th December 2007, 06:56 AM	#2
Colt45 diyAudio Member Join Date: Feb 2002 Location: Canada	Sure why not. As long as dissipation isn't much over ratings, and ambient is a human survivable environment, it shouldn't matter... Which is probably why it isn't mentioned in the datasheet.

11th December 2007, 11:48 PM	#7
coyotesgator diyAudio Member Join Date: Sep 2007	I appreciate all of the replies. Thank you to all. As the other octals around it aren't really very hot, and the base is considerably cooler, I'm probably alright. Besides, I kind of enjoy the little room heater. Rob

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