Transporter SMPS

[DaveBk]

Hi All,

There have been a number of threads on improving the Squeezebox power supplies, but I've never seen anything similiar about the Transporter. I realise that the Transporter's DSP, DAC and Analogue audio sections are powered by very high quality linear regulators, but the CPU and display is powered by an off the shelf SMPS from Unifive. It's a UOP310 5v 12w unit, but I can't find much about it in terms of noise, EMI etc.

Could any audible improvements be made by replacing this with a linear equivalent or al least physically sheilding the unit within a separate enclosure within the Transporter case.

Any thoughts appreciated.

[Phil Leigh]

Hi All,

There have been a number of threads on improving the Squeezebox power supplies, but I've never seen anything similiar about the Transporter. I realise that the Transporter's DSP, DAC and Analogue audio sections are powered by very high quality linear regulators, but the CPU and display is powered by an off the shelf SMPS from Unifive. It's a UOP310 5v 12w unit, but I can't find much about it in terms of noise, EMI etc.

Could any audible improvements be made by replacing this with a linear equivalent or al least physically sheilding the unit within a separate enclosure within the Transporter case.

Any thoughts appreciated.

It's certainly possible - but I bet Sean has seen to it that actually this area is pretty well covered. One cheapish trick you could try is a fully shielded mains lead replacement (£30 from Maplin). This might help prevent RF crud (if there is any) from the SMPS getting out into the rest of your gear. Others may disagree,
Cheers
Phil

[DaveBk]

I'm massively impressed with the thought, care and engineering excellence Sean and the team have put into the Transporter so hopefully he will reply and put my mind to rest. My question was to an extent prompted by the problems Naim experienced with the early HDX units where the SMPS 'pollution' impared the listening experience even when it was not the active source. They've worked hard to improve this by adding ferrites in key places.

Thanks

[seanadams]

It's not only a very quiet supply, but it is also thoroughly isolated from all the audio circuitry. You can put a linear supply in there if you want, but if I had any reason to believe that would improve sound quality I would have done it for you.

If you're concerned about EMI inside the case, there are a hundred other components in there to consider, and you should really be using a spectrum analyzer and near field probe to figure out if your changes are making things better or worse. Just because a power supply is easy to replace does not mean it's good idea!

[Phil Leigh]

...as I was saying, if Sean...

Seriously though, I get the feeling that the TP was designed up to a spec and rather less down to a price.

In some ways (which will make Sean chuckle) it suffers from its lack of audiofool trappings - over the top copper case weighing half a ton, anti-vibration feet made of exotic hardwoods - that sort of thing! )

[DaveBk]

Thanks for the reply Sean - as I hoped and expected, just felt compelled to ask... Did you look at or test other SMPS modules before selecting the Unifive unit? The specs on their web site are rather limited.

Wish I had a spectrum analyser... best I can do is an aging 20Mhz 'scope with a paperclip on the end of the probe...!

And regarding the audiofool stuff, my Naim kit does have VERY heavy cases, but discrete black ones - no inch thick copper, or exotic woods in sight!