UPS Supplies Sonics Question.

[mrfeedback]

I got given a bunky 1200VA UPS supply today - another thing for me to fix.
Does anybody have experience of running such supplies as the 240VAC source, with the UPS unplugged from the mains input supply, and any sonic advantages ?.
Any experience of isolating such a system from any grounds, or earthing to a dedicated earth stake ?.


Eric.

[Peter Daniel]

I'm using UPS for my front end (DAC and active crossover) and transport cannected directly to the mains.

Some people sau UPS don't sound good, but in my setup I hear an improvement. It may be because it somehow separates AC supply from 2 digital components (DAC and transport) so they don't contaminate each other. Also, when I unplug UPS and run from battery, there is a further improvement in depth and imaging. Here's the pic of mu UPS http://www.diyaudio.com/forums/showt...5209#post35209

[Sparhawk]

I imagine it would depend highly on the particular UPS used. Some small, cheap models have a modified square wave output, full of harmonics. On the other hand, the better models have very low THD on the output, potentially lower than utility power.

Note that isolating the ground and using a separate ground rod both violates code, and is potentially dangerous. What you could do, though, is run an isolated ground back to the main ground point in the house.

[mrfeedback]

Hi Peter,
I spent an hour after work this arvo at an electrician friends place diagnosing a 12kVA UPS and these things are a whole different thing - AUS$12,000 or so, and a truckload of expensive electronics and high power components.
He gave me the 'baby' 1200VA one that would have gone to the recycling center - now it is in my recycling center.
Your results sound encouraging - the transformer in mine is rather bigger than in yours - maybe that is a benefit ?.
Have you tried powering your new Gainclone and front end from your UPS ? - more portable to downstairs than your Alephs !.
Have you followed the 'Sound of Chassis' thread involving Frank and I ?.

Regards, Eric.

[Peter Daniel]

Actually, I have another UPS downstairs and I can check it on gainclone. Mine is only 600W that's why transformer is smaller. My front end can operate for about 2 hours on battery.

I keep an eye on the chassiss thread.

[mrfeedback]

"Note that isolating the ground and using a separate ground rod both violates code, and is potentially dangerous. What you could do, though, is run an isolated ground back to the main ground point in the house."
If running a complete system from a UPS that is disconnected from the mains, then presumably effectively you have a portable CD/Radio Cassette running from a balanced isolated 240V supply - floating so no electrical code earthing issues are involved.
The dedicated earth stake question was to find if any sonic differences arise between keeping the system floating or grounded, and away from noisey building earths.

Eric.

[mrfeedback]

Not tried the Feedback Frugalphile Isolators (Tm) yet ? - do it and you'll like it I reckon.

"Actually, I have another UPS downstairs and I can check it on gainclone."
You should try that too I reckon - I'm interested to hear of your results.

Eric.

[Sparhawk]

Originally posted by mrfeedback
If running a complete system from a UPS that is disconnected from the mains, then presumably effectively you have a portable CD/Radio Cassette running from a balanced isolated 240V supply - floating so no electrical code earthing issues are involved.

I suppose there are no issues as long as the UPS is disconnected from the grid. But as soon as you plug it back in to charge it...

Hmm, maybe I should bring my system to work, plug it into our 40KVA ups sytem, and see how it sounds...

[fdegrove]

Hi,

I suppose there are no issues as long as the UPS is disconnected from the grid. But as soon as you plug it back in to charge it...

As long as it is connected to the mains a UPS only works as a buffer btween the mains and whatever is hooked up.

Only when the mains fails does it come into play...that is when you may hear a sonic difference.

Cheers,

[mrfeedback]

Depends what sort - online or offline.
Online types consist of input-rectifier-batteries-invetor-output, so is always generating from the battery DC supply.
Offline types switchover to invertor operation when input AC fails, and then the invertor stage starts.
Cheaper PC types are usually offline types.

Eric.