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Old 20th March 2005, 04:05 PM   #1
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Default EF86 Triode Mode

Hi All,

When running an EF86 in triode mode, is there any advantage to be gained by inserting, say, a 100e resistor between the Cathode & G3, or should one just strap the two pins together? Would a resistor affect the gain or any other characteristic of the valve?

The EF86 is the first stage of a Mullard 5-20. The HT & Cathode resistors have been changed accordingly to give about 1v DC on Cathode & correct Plate voltage.

-Eric
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Old 20th March 2005, 08:45 PM   #2
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Default Re: EF86 Triode Mode

Quote:
Originally posted by Family_Dog
Hi All,

When running an EF86 in triode mode, is there any advantage to be gained by inserting, say, a 100e resistor between the Cathode & G3, or should one just strap the two pins together? Would a resistor affect the gain or any other characteristic of the valve?


Hi there.....inserting a resistor on the g3 brings no performance advantge and will pick up noise.....so connect g3-->cath. It isn't in tube data sheet.
Make sure that pins 2 or 7 (or both) are connected to chassis.
see www.frank.pocnet.net/index.html

richj
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Old 21st March 2005, 03:45 AM   #3
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Hi Rich,

Thanks for your reply. I have built four amplifiers with the Cathode & g3 shorted out, and one with a resistor betwee the two terminals. Although I couldn't hear any difference between the amplifiers, I was wondering which would be the correct way to go, and the reasons behind the fact.

I will remove the resistor from the one amplifier and short the pins out. With the input shorted and 'scope set at 10mV/div, I could detect absolutely no noise on any of the amplifiers on any of the amplifier's speaker outs.

The link you gave seems not to exist?

-Eric
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Old 21st March 2005, 04:16 AM   #4
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Try this link:
http://www.mif.pg.gda.pl/homepages/frank/index.html
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Old 21st March 2005, 04:41 PM   #5
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Hi Jason,

Got it, thanks!

-Eric
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