How is wattage calculated when only using a single section?

phrarod · 11th May 2010, 09:17 PM

I'm only using half of a 5965 which states the maximum wattage is 2W. I'm already over that but if I'm using a single section is the max wattage then 4W?

I can't find any information on this.

SGregory · 11th May 2010, 09:21 PM

GE Tubesheet says 2.2 watt each plate or a total of 4 watts for both. Design Maximum.

phrarod · 09:28 PM

I'm running 2.20 on a single plate. What are the consequences? BTW, this is a 7062 which is supposed to be fairly identical to the 5965 but the data sheet says 2W max anode. http://tubedata.milbert.com/sheets/009/e/E180CC.pdf

hemgjord · 11th May 2010, 09:28 PM

I've never seen any references that states that you can exceed the dissipation limit if you only run one section. Normally it's thee other way around, the max dissipation is listed per section and sometimes there is a more strict limit for both sections combined. One extreme example is the 6BX7 which has a 10W per section limit but only 12W for both sections.

/Olof

phrarod · 11th May 2010, 11:03 PM

I just went up some in resistance on the cathode and now I'm running 2.07W on one side and 1.97W on the other. According to the datasheet I'm still over. What is a target number would you think to reach? 1.8W 1.9W

Arnulf · 11th May 2010, 11:58 PM

Look, it's a tradeoff: dissipation versus lifespan, and with higher dissipation comes the increased linearity.

How long do you want your tube to last ? People have run EL84 in RF duty (!) at 30+W (!!). Yes, it didn't as last long as specified in datasheet, but it worked while it did.

Run your tube close to datasheet's specified maximum dissipation and you're likely to get the datasheet's suggested lifespan of what, 1-5K hours. Run your [preamp] tube (which is what you've got there) at lower than maximum disipation and it will last "forever".

phrarod · 12th May 2010, 12:31 AM

Thanks for the education. Yes, I can live with replacing the tubes every year or couple years if they need it. I wasn't sure if I was causing harm like a meltdown inside the tube.

That clears it up. This circuit sounds best running over 11mA of bias currant. Just going up to 249 and dropping the wattage down to 2.07W from 2.20W dropped the bias current to around 10.2-10.5 whereas it was at 11.2-11.5 which sounded better.

By the way I'm running the 'naked' resistors by Texas Corp. Really transparent.

11th May 2010, 09:17 PM	#1
phrarod diyAudio Member Join Date: Aug 2005	How is wattage calculated when only using a single section? I'm only using half of a 5965 which states the maximum wattage is 2W. I'm already over that but if I'm using a single section is the max wattage then 4W? I can't find any information on this.

11th May 2010, 09:21 PM	#2
SGregory Tubie Noobie diyAudio Member Join Date: Apr 2003 Location: Southern Tier NY	GE Tubesheet says 2.2 watt each plate or a total of 4 watts for both. Design Maximum. __________________ Living Life Doing the Waltz in 4/4 meter.

11th May 2010, 09:22 PM	#3
phrarod diyAudio Member Join Date: Aug 2005	I'm running 2.20 on a single plate. What are the consequences? BTW, this is a 7062 which is supposed to be fairly identical to the 5965 but the data sheet says 2W max anode. http://tubedata.milbert.com/sheets/009/e/E180CC.pdf Last edited by phrarod; 11th May 2010 at 09:28 PM.

11th May 2010, 09:28 PM	#4
hemgjord diyAudio Member Join Date: Apr 2007	I've never seen any references that states that you can exceed the dissipation limit if you only run one section. Normally it's thee other way around, the max dissipation is listed per section and sometimes there is a more strict limit for both sections combined. One extreme example is the 6BX7 which has a 10W per section limit but only 12W for both sections. /Olof __________________ I'm not allowed to do magic, union rules...

11th May 2010, 11:58 PM	#6
Arnulf diyAudio Member Join Date: Feb 2009	Look, it's a tradeoff: dissipation versus lifespan, and with higher dissipation comes the increased linearity. How long do you want your tube to last ? People have run EL84 in RF duty (!) at 30+W (!!). Yes, it didn't as last long as specified in datasheet, but it worked while it did. Run your tube close to datasheet's specified maximum dissipation and you're likely to get the datasheet's suggested lifespan of what, 1-5K hours. Run your [preamp] tube (which is what you've got there) at lower than maximum disipation and it will last "forever". __________________ mod verb, transitive /mod/ to state that one is utterly clueless about the operation of device to be "modded" and into "fixing" things that are not broken; "My new amplifier sounds great so I want to mod it."

11th May 2010, 11:03 PM	#5
phrarod diyAudio Member Join Date: Aug 2005	I just went up some in resistance on the cathode and now I'm running 2.07W on one side and 1.97W on the other. According to the datasheet I'm still over. What is a target number would you think to reach? 1.8W 1.9W

12th May 2010, 12:31 AM	#7
phrarod diyAudio Member Join Date: Aug 2005	Thanks for the education. Yes, I can live with replacing the tubes every year or couple years if they need it. I wasn't sure if I was causing harm like a meltdown inside the tube. That clears it up. This circuit sounds best running over 11mA of bias currant. Just going up to 249 and dropping the wattage down to 2.07W from 2.20W dropped the bias current to around 10.2-10.5 whereas it was at 11.2-11.5 which sounded better. By the way I'm running the 'naked' resistors by Texas Corp. Really transparent.

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