Isolated/Independent Power Supply/Circuits?

[ensoll]

I was at a dealer yesterday that was very much a true believer audiophile (he had some of his electronics up on wooden blocks because it 'improves the sound'). He carried all kinds of high end electronics but was a huge fan of Ayre products. Most of what he was talking about is not worth serious consideration but one question I have is about discrete circuits/power within electronics. Many of the high end electronics (whether it's a receiver, cd player, or whatever) advertise isolated power supplies and other isolated components to reduce noise. Where does this fit on the spectrum of real issues?

I don't question that power supplies can generate noise/interference but how big of an issue is this in modern, well designed electronics? To put this in perspective I am planning on purchasing some Paradigm Studio 100's and the two dealers I've spoken with says these can be driven fairly well with just a nice receiver (a separate amp would help but probably not enough to justify the cost of the amp). I'm just trying to figure out how much value the "isolated circuit boards" and "isolated amplifier" features actually have in electronics.

 

[highfigh]

If you know anyone who has mono-block amps, this is taking it a couple of places farther. If all stages are isolated, they can't have any crosstalk or other influence over each other. If one channel is sucking a lot of juice, it won't affect the other the way it would if they shared the power supply. If they do this in the preamp section too, it sounds like they really want to make something special. The only thing they can't get away from easily is sharing the power service ground.

It's not new, it's just their version. I have an old Conrad Johnson MV-45 and I had them e-mail the schematic- it's one channel and only the B+ and chassis are shared. The ground planes are separate.

That said, some of the receivers, pre-amps and DVD/CD players I have been seeing show S/N of >100dB. In most cases, no noise will be heard. I don't know how much more quiet they can make it- the best S/N I have seen lately is 130dB and for all practical purposes, that's more than quiet enough.

 

[highfigh]

If you know anyone who has mono-block amps, this is taking it a couple of places farther. If all stages are isolated, they can't have any crosstalk or other influence over each other as long as everything is shielded properly. If one channel is sucking a lot of juice, it won't affect the other the way it would if they shared the power supply. If they do this in the preamp section too, it sounds like they really want to make something special. The only thing they can't get away from easily is sharing the power service ground.

It's not new, it's just their version. I have an old Conrad Johnson MV-45 and I had them e-mail the schematic- it's one channel and only the B+ and chassis are shared. The ground planes are separate.

That said, some of the receivers, pre-amps and DVD/CD players I have been seeing show S/N of >100dB. In most cases, no noise will be heard. I don't know how much more quiet they can make it- the best S/N I have seen lately is 130dB and for all practical purposes, that's more than quiet enough.