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turretslug · 18th Nov 2015, 9:34 pm

I wonder if this is part of the reasoning behind the wave of ex-BT "mains conditioning units" that appeared on the surplus market a few years back in ratings from 125 to 1,000VA? I got a couple of 250VA ones for a tenner a while back from a BT guy who had a garage-full- "not sure what these are for...."- intending to use them with cabin receiver Eddystones and the like as they are essentially a 1:1 transformer with one side of the output connected to case, i.e. blue and green/yellow commoned on the output socket. There are what appear to serve as a resonator capacitor and an RC snubber on the output winding- presumably, as well as DC component blocking, there's an element of smoothing out the shape of a mains waveform that's been distorted by electronic loading.

I have to say that I was always a tad sceptical of the audiophile mains conditioner market, seeing them as (sometimes very!) expensively dressed up versions of the above devices but if they let buzz-prone transformers run quiet when there's an appreciable DC supply component, then there's at least sound (!) reasoning behind the idea.

18th Nov 2015, 9:34 pm	#23
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,395	Re: How much DC on your mains ? I wonder if this is part of the reasoning behind the wave of ex-BT "mains conditioning units" that appeared on the surplus market a few years back in ratings from 125 to 1,000VA? I got a couple of 250VA ones for a tenner a while back from a BT guy who had a garage-full- "not sure what these are for...."- intending to use them with cabin receiver Eddystones and the like as they are essentially a 1:1 transformer with one side of the output connected to case, i.e. blue and green/yellow commoned on the output socket. There are what appear to serve as a resonator capacitor and an RC snubber on the output winding- presumably, as well as DC component blocking, there's an element of smoothing out the shape of a mains waveform that's been distorted by electronic loading. I have to say that I was always a tad sceptical of the audiophile mains conditioner market, seeing them as (sometimes very!) expensively dressed up versions of the above devices but if they let buzz-prone transformers run quiet when there's an appreciable DC supply component, then there's at least sound (!) reasoning behind the idea.