0dbfs

Using only half of dual triode. Ground unused half?
« on: February 01, 2010, 12:58:32 PM »
Hi,

I am using half of a dual triode in a tube mic circuit.

I was wondering if it is best to ground the tube connections for the half that is not used. ie; A2, G2, K2...

Thanks in advance!

Best,
j
Music is everything!
Audio is everything else!


rodabod

Re: Using only half of dual triode. Ground unused half?
« Reply #1 on: February 01, 2010, 01:07:56 PM »
Yes. You may as well just run one heater too.
Quote from: tv
punchy fat bastard chip

0dbfs

Re: Using only half of dual triode. Ground unused half?
« Reply #2 on: February 01, 2010, 01:31:12 PM »
Roddy,

Thanks!

This tube is a 6BS8:
http://tubedata.itchurch.org/sheets/093/6/6BS8.pdf
Used in the Bulldog 49 circuit.
That tube in particular shows no connection for pin9 as being the heater center tap. I'll measure to confirm that just for fun though.

I was posing the question for general information although I did not ground those connections when I initially assembled mine. I'll have to sort that out soonest.

If the single heater connection heats both cathodes, what affect might leaving the second unused half of the triode ungrounded have?

Best,
jonathan
Music is everything!
Audio is everything else!

PRR

Re: Using only half of dual triode. Ground unused half?
« Reply #3 on: February 01, 2010, 07:36:37 PM »
> what affect might leaving the second unused half of the triode ungrounded have?

Probably very little.

Ya know, 6J6 is the same triode except common-cathode. Which does not matter to you. And there were bazillions of 6J6 made; I never knew there was a 6BS8.

0dbfs

Re: Using only half of dual triode. Ground unused half?
« Reply #4 on: February 02, 2010, 10:37:48 AM »
PRR,

> what affect might leaving the second unused half of the triode ungrounded have?

Probably very little.

Thanks for the input! Seems like grounding the unused pins might make for a "best practice" in any case.

Ya know, 6J6 is the same triode except common-cathode. Which does not matter to you. And there were bazillions of 6J6 made; I never knew there was a 6BS8.

The 6J6 looks interesting in a 7 pin base opposed to the 9 pin 6BS8. Common cathode is interesting as well. Datasheet explains that it is ideal for parallel or push/pull with parallel plates operation.
I might try some different tubes in my situation (other than the 6BS8) as well just to see the differences.

Best,
jonathan
Music is everything!
Audio is everything else!


 

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