UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Ed_Dinning · 20th Oct 2020, 8:35 pm

Hi, try checking the heater voltage applied to the valve is correct with a good meter. This can vary a lot if your mains is also varying. The transformer I designed for the Sussex has multiple primary taps to get over this problem, but will not compensate if the voltage is varying rapidly, or if the mains waveform is poor (not sinusoidal) as can happen with heavily loaded power systems.
For accurate results a true RMS meter is needed.

Ed

20th Oct 2020, 8:35 pm	#1595
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: The "Sussex" Homebrew Valve Tester. Hi, try checking the heater voltage applied to the valve is correct with a good meter. This can vary a lot if your mains is also varying. The transformer I designed for the Sussex has multiple primary taps to get over this problem, but will not compensate if the voltage is varying rapidly, or if the mains waveform is poor (not sinusoidal) as can happen with heavily loaded power systems. For accurate results a true RMS meter is needed. Ed