Max grid resistance for GM70?

kavermei · 16th September 2010, 05:11 PM

Hi

anybody know what the maximum grid resistance is for the GM70 in fixed bias?

TIA
Kenneth

Rod Coleman · 16th September 2010, 08:35 PM

Don't have a specification, but it would be a low value. It's designed to work with positive grid voltages.

The similarly-scaled pentode, the GK71, is rated to have a Maximum grid leakage current of 30uA, when running 83 .. 100mA in the anode - I would imagine one should work with at least that much leakage, and gas will add to it, because of the years of storage.

kavermei · 17th September 2010, 04:57 AM

Thanks Rod,

I'm using 47k in my build right now, so I hope it will work out okay. It's the lowest I can get without overburdening the driver.

Kenneth

16th September 2010, 05:11 PM	#1
kavermei diyAudio Member Join Date: Jan 2005 Location: Lokeren, Belgium	Max grid resistance for GM70? Hi anybody know what the maximum grid resistance is for the GM70 in fixed bias? TIA Kenneth __________________ Never send a human to do a machine's job. --Agent Smith

17th September 2010, 04:57 AM	#3
kavermei diyAudio Member Join Date: Jan 2005 Location: Lokeren, Belgium	Thanks Rod, I'm using 47k in my build right now, so I hope it will work out okay. It's the lowest I can get without overburdening the driver. Kenneth __________________ Never send a human to do a machine's job. --Agent Smith

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16th September 2010, 08:35 PM	#2
Rod Coleman работник diyAudio Member Join Date: Jul 2004 Location: Warwickshire UK	Don't have a specification, but it would be a low value. It's designed to work with positive grid voltages. The similarly-scaled pentode, the GK71, is rated to have a Maximum grid leakage current of 30uA, when running 83 .. 100mA in the anode - I would imagine one should work with at least that much leakage, and gas will add to it, because of the years of storage.

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