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Ed_Dinning · 10th Nov 2020, 3:03 pm

Hi Richard, thanks for all the work on the PSU and the details from the AP's.

The DC heaters are a must, I'm told, when using the transmitter to reduce the 50Hz mod.

I've used a FET for the 1155 filter and made it adjustable as it is easily done. This is more of an active filter for hum reduction than a true compensated regulator. I'm told the limited range adjustment (200 to 240V) makes it easier to find a low drift point for the 1155 oscillator.

The EHT supply seems to benefit from an LCL filter where the first choke is a swinging type. It is also possible with some of the transformers available to have hi/lo EHT switching

There is a significant noise reduction if the HT and EHT negative rails are bypassed to ground with a 0.1uF paralleled with a 1Meg.

Ed

10th Nov 2020, 3:03 pm	#39
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,196	Re: R1155 Modern Power Supply Hi Richard, thanks for all the work on the PSU and the details from the AP's. The DC heaters are a must, I'm told, when using the transmitter to reduce the 50Hz mod. I've used a FET for the 1155 filter and made it adjustable as it is easily done. This is more of an active filter for hum reduction than a true compensated regulator. I'm told the limited range adjustment (200 to 240V) makes it easier to find a low drift point for the 1155 oscillator. The EHT supply seems to benefit from an LCL filter where the first choke is a swinging type. It is also possible with some of the transformers available to have hi/lo EHT switching There is a significant noise reduction if the HT and EHT negative rails are bypassed to ground with a 0.1uF paralleled with a 1Meg. Ed