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In the Forum: Melquiades Amplifier
In the Thread: Single-stage Melquiades vs. DHT amps

Post Subject: Less is more... usually.Posted by floobydust on: 2/23/2009

A slightly lower filament voltage is okay for a coated filament (not for a Thoriated-Tungsten filament however). There was some testing done some time ago on this and findings indicated an increase in tube life and lowered distortion. I just don't recall where the link was to the test data. A pair of 1-ohm would resistors would drop the filament voltage close to 2.1 volts. This is a 16% drop and may skew the operating parameters slightly. If your plan is to use the same 6.3VAC transformer, I would skip the split balance technique as you no longer have a very low DC (resistance) path to each filament end (being the filament winding).

Regards, KM

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