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peter foster wrote:

The UPS units are being used in their normal way, as line interactive.  The voltage waveform supplied by the Powerware 5115 is a sine wave.  This is described briefly in the manual and was important information for me pre-purchase.  At the time of my investigations, I consulted a number of people with expertise in the field of mains power supply regulation and amplifier and transformer design and came to the conclusion that the minimum requirement was for a perfect sine wave output, no fan and for a unit that was proven with large scale commercial server systems.  After receiving one unit and testing it the results were acceptable and the cost reasonable so I then purchased more.  There is also a manufacturers warranty supplied for equipment connected to the UPS units.

Peter, I am sorry to inform you but it is not exactly what it is, and I am surprised how people in the fields did not explained it to you. The line-interactive unit buy definition have no own waveform what power is present.  You might Google the definition of line-interactive UPS unit of you might look at my file: (figure #2)

http://www.goodsoundclub.com/PDF/UPS.pdf

As you might see the line-interactive what the power is there work in complete bypass mode and the own DC to AC inverter is not activated. If you put a scope before and after the line-interactive UPS unit then you will see absolutely identical waveform before and after. The UPS unit will filter some HF noise but it is about it. Without the input power the line-interactive begin to regenerate a new own waveform. The quality of that waveform and that electivity for audio is a separate subject. I did test 3 commercial line-interactive UPS units, including two large and expansive – none of them I found were useful, at least as is.

peter foster wrote:

But that is only part of the story.  The other parts include use of a dedicated branch line for each unit and perhaps even more importantly the design of the amplifier power supply itself which can do much to supply consistent performance with inconsistent mains power supply.  The schematic for the amplifier power supply is described at http://www.turneraudio.com.au/8585-amp-october-2006.html if you are interested.

Yes, I did detect with my own experience that the more chokes in supplies, partially the input chokes the less sensitive amp for electricity problems. Voltage anomalies are just a part of the story. In class A amp the current consumption is constant but current flow atop of voltage waveform, that most of the time is truncated. So, we can stabilize currant without caring about voltage. How? The input chokes that store current and that demonstrate current inertia even if voltage sinks, also chokes are effective low-pass filter against the line noise (thought they do not work at UHF, you would need different chokes for that). As far as I concern, more chokes and higher current make amps less care about power problem. I have written that Super Milq is way less sensitive to power problems then my front end.

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