Could a 'Computer-Grade' UPS be the poor man's eqivalent to Audiophile Power Regenerators?

[Regg]

It may be a long shot, but I was wondering if anyone here has ever used a commercially available UPS as a means of protecting and supplying their audio equipment with clean power, if such a thing is possible.

 

I've seen a few recommendations on various other audio forums for computer grade UPS devices from Liebert, Tripp Lite, CyberPower, APC, etc. It's usually suggested that the important thing to look for in a UPS for audio-related applications is that the device should be a True Online, Double-Conversion system, which supposedly ensures pure sinewave form output and the cleanest, most compatible AC output for computers and any other critical load, which hopefully includes audio equipment.

 

But is that just marketing fluff? It's not like most of us have an oscilloscope handy to confirm the 'Pure Sinewave' claims. And are these devices comparable to the AC regeneration systems from the likes of APS PurePower and PS Audio?

 

Any thoughts or comments are greatly appreciated.

 

[fmak]

If you look at the waveform of even 'pure sine' ups supplies, not only is the waveform not sine, but it can contain loads of harmonics.

 

 

 

 

[Thomas J]

Hi, if you're interested in good power conditioning for cheap, and you can accommodate poor aesthetics, and you are handy with a soldering iron (to remove the fan), purchase an Elgar 6006B from eBay. If you wait, you can get one for $100. They give equivalent performance, IME, to the Accuphase models, which I think actually copied the Elgar circuit (buck-boost). Their original purchase price was something like $6,000. They're very good machines.

 

[fmak]

As far as I know, this is a dc-dc type of switch mode unit.

 

The Accuphase is a feed forward distortion cancellation design. There are no fans and no switching element.

 

Can you clarify what you mean?

 

[One and a half]

manufactures a sine wave by making changes to it's output by comparing a reference. Changes are made by adding/subtracting and SHAPING the waveform. The power supply does a lot more than just create a sine wave, it can cope and compensate for some very ugly artifacts generated by the load (harmonics) and corrects for them so that the output sinewave distortion is kept at 0.22% or under. Hence the price. It is one piece of very smart engineering.

The Elgar units are industrial line conditioners, whereas the Accuphase is designed specifically for audio uses.

 

 

[fmak]

Actually, the thd of Accuphase units is 0.1%.

 

I can find no clear details of the Elgar 6006B which may well be a bargain if it is a decent regenerator.

 

I have 2 Accuphases, 500W and 1200W as well as a Powerplant 300W. I am happy with all of them. They are essential in making hirez digital replay that rivals analog.

 

[One and a half]

can generate a perfect waveform, when you don't have any loads connected to them. As soon as you introduce a load like an amplifier or worse, a PC/Mac, you end up with a mess on the UPS output. Nothing much you can do about this, unless the UPS compensates to eliminate the distortions. Consumer level UPS do not do this.

Technically, an offload UPS is just fine for audio or PC applications, the switching time from battery when the mains power is loopy is enough to keep going.

Double conversions UPS is dearer, can be isolated and have a true no break to the output. These are necessary for operating theatres for example where any interruption is inconceivable.

As for sonic benefit? I rather a transformer/line conditioner as it's passive, very reliable and a very good start to getting rid of common mode noise in itself. Put a UPS in front of the transformer, if you have issues with black or brown outs.

 

[Thomas J]

The Elgar is a buck-boost topology that works on the exact same basis as the Accuphase. I've used both for years, and have upgraded Elgars extensively. You can find a schematic here:

 

http://www.programmablepower.com/products/Products_Discontinued.htm

 

The 6006B is listed under "Ultra Precision Line Conditioner." Schematics are included in the manual, as well as parts lists and layouts.

 

As for upgrading, Elgars respond well to upgraded capacitors and resistors throughout, to a shortening of wiring where appropriate, and to replacement of the sensitive op-amp supplies with good shunt or series units.

 

The Elgars are built like a tank. I've yet to see a high-end audio component built as well.

 

[johniboy]

This is an interesting thread! I just moved and encountered a real problem and hope that you guys can help me out. If I turn on/off certain lights in my listening room, I experience music dropouts. I have a dcs elgar plus dac and it loses the signal for a short period of time. For a second it goes into "testing..." and then re-locks the signal. The computer source or the amp does not seem to be affected. This did not happen in my former apartment!!

 

Any ideas whether an UPS would help? Any suggestions for a decent European version (220V) that does not cost 1000s of dollars? If I have these issues with my DAC, do I need to also take care of my computer and amp?? I can remember that others had similar issues with their power circuits but I can´t find the thread anymore to look up the solutions...

 

Thank you for your help in advance!

 

[johniboy]

http://www.apc.com/resource/include/techspec_index.cfm?base_sku=LE1200I&ISOCountryCode=us

 

???

 

[jonmarsh]

When your power circuits are switching, they develop transients relative to the line neutral, which is at "ground" potential (sort of, mostly), and can generate high common mode dv/dt which is triggering noise injected into the digital path. With ideally balanced circuits (difficult to achieve in practice) this common mode noise wouldn't affect things, but in practice, a small imbalance in the circuit, when presented with a high common mode dv/dt, can generate an interfering noise signal. This is one reason why pro folks are often happy to spend a hundred bucks or more on a well made Jensen transformer, instead of relying on cheaper active balanced circuits that don't hold up under these kinds of conditions.

 

The easiest/best solution I've setup for a friend with this problem was to put all of his digital hear and preamp on a balanced power isolation unit. These are available commercially, though I've just usually done it them DIY with Plitron transformers.

 

Another type of unit that works will is a ferroresonant line transformer- these are heavy and large, too, though they do help with both regulation and filtering transients.

 

[johniboy]

Thank you jonmarsh,

 

I just looked up the elgar manual. This is what is says:

"If the AC supply is momentarily interrupted or is more than 20% below it´s rated voltage, the unit display PowerDn and mutes the audio outputs to protect your loudspeakers from damage. This may be caused be loose AC power wiring, local power-line overloads or heavy-duty appliances line air conditioners."

 

Now that is scary. More than 20% below its rated voltage... I thought I live in a civilized country (Germany)!

 

jonmarsh, do you know of a company in Europe that sells balanced power isolation units or ferroresonant line transformers??

 

[jonmarsh]

But there is inductance in the power lines and the wiring in your home, and when a piece of equipment switches on that causes a brief current spike, this spike will pull down the line voltage momentarily, very briefly, generating a high dv/dt noise spike. It is the noise spike that is the problem- your audio and digital equipment has plenty of storage capacitance to ride out this spike- remember that typical linear supplies with rectifier input to capacitors only conduct current into the storage capacitors at the peak of the waveform.

 

You might even be able to get some relief just by combining all of the equipment onto a filtered outlet system, such as some of the audiophile and home theater equipment sold in the US, which may incorporate enough line filtering to control the effect of this transient.

 

Though I work for a German company, it is in the US, and I don't really have any knowledge about who would sell in Europe- though the larger players over here may. Furman Power makes a lot of these types of products, including some balanced power conditioners- you might check into them for a start. I suspect that simple surge protection will not be enough.

 

[jtwrace]

I'm really thinking of trying an Elgar 6006B.

 

Anymore feedback on them?

 

[jtwrace]

Nobody?