Transformers: Auto- vs. Isolating

Sean, you mentioned vast difference in quality... Do you now anything good or bad about those offered on sites such as http://www.220-electronics.com/, etc?
On the mentioned above web site 1.5Kw transformer costs about $120, made in China. On the other side Hammond from Canada sells 1.5Kw for about $350. I guess there is something in that, how can it affect sound?

Dmitry: Those are not isolation transformers. They are voltage converters and there is a BIG difference. For one thing a "decent" 1.5KVA isolation transformer will weigh at least ( at the bare minimum ) 30 lbs by itself. I'm talking about just a transformer with no case or chassis weight added. The more "plates" in a transformer, the more it will weigh and the less likely it is to saturate under heavy loads. As a case in point, the 3.0 KVA transformers that i'm using weigh over 100 lbs apiece. This is bigger / heavier than some 5.0 KVA units that i've seen.

While there is more to finding a good isolation transformer than just sheer weight, it is a good starting point. The other major factor would be the internal capacitance rating ( a lower number is better like .00X ) and that of the rate of attenuation ( lower is better here too with -126 being better than -80 etc... ).

What are you trying to do and what country are you located in ? If outside of the USA, what voltage and frequency does your AC system run on ? Sean
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Sean, thank for the reply. I'm in Canada, but I may have to go to 220V/50Hz area for some time. After my recent upgrade of almost whole system, I can't afford 'perfection' anymore :), and thus I'm looking for the economical way to feed my system with European voltage, meaning to compromise sound quality the least possible. Your advise?

Any more details, please!

This discussion is an example of a philosophy of sizing AC power components (transformers, power cords, house wiring, etc.) so as to provide the peak power requirement, which, as we all know, far exceeds the average. This is necessary because there is no device (other than the spinning momentum of an alternator) that can store AC power.

However, almost all the AC is used to generate DC power, and there are devices, capacitors, that store DC. At one time a popular Mod to audio power amplifiers was a bank of outboard capacitors. It seems to me that this is a better, and less costly, way to provide greater reserve power.