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Stylo N M · 16th Feb 2018, 2:09 am

If I were you, I would resist the temptation to do too much messing about with the heater voltage. Anything below 1.3 volts will result in the valve dropping off due to insufficient electrons being produced by a poorly heated filament.

Now a word of warning, anything above 1.6 volts and you're more than likely to destroy the heater filament in EVERY VALVE in the set. The fact of the matter is there isn't much tolerance to play with, so don't do it.

You will find it quite supprising how long just two modern alkaline AA batteries in parallel will power the LT circuit for.

Paul.

16th Feb 2018, 2:09 am	#20
Stylo N M Heptode Join Date: Jul 2012 Location: Derby DE1, Derbyshire, UK. Posts: 626	Re: AD35/B126 Batteries If I were you, I would resist the temptation to do too much messing about with the heater voltage. Anything below 1.3 volts will result in the valve dropping off due to insufficient electrons being produced by a poorly heated filament. Now a word of warning, anything above 1.6 volts and you're more than likely to destroy the heater filament in EVERY VALVE in the set. The fact of the matter is there isn't much tolerance to play with, so don't do it. You will find it quite supprising how long just two modern alkaline AA batteries in parallel will power the LT circuit for. Paul.