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Balanced vs standard power

Searching for an Isolation Transformer 10 or 15kva. I have the budget for Equitech but I'm sold only on the benefits of isolation and not "yet" on the benefits of balanced power unless one is recording live musicians. My rationale is that most if not all audio components are not designed with balanced power so they may be optimal performers with standard power and lesser performers with balanced power. Until someone does a side by side comparing isolated balanced to isolated standard power we may never know.

I have read the various threads regarding isolation transformers from Equitech 10wq, MGE Topaz etc, and the Euqitech stereophile review. For larger non-balanced options there is Ultra K 600 with K factor correction and triple shielding from the Controlled Power Company. They range from 5 to 25 kva.

I think supersizing Isolation transformers for audio is not well recognized yet because no one has done the necessary review/ comparisons to determine the performance curve of Isolation Transformer size to Audio Performance. Although Isoclean advocates the use of two of their Isolation Transformers for each piece of equipment. Maybe they're trying to tell us something or just sell more transformers. 10 KVA is "plenty" for my system according to Martin at Equitech, but "plenty" is not quantified enough to convince me, so I 'm leaning toward the 15kva on the Ultra K 600 from Controlled Power about $4000 vs Equitech 15 kVA at upwards of $14000.
natan6355
zmanastronomy's avatar
zmanastronomy
738 posts
 
Good info Ngjockey. I just picked up a Signal DU-5 on ebay. I'm going to use it wired in balanced mode for my amp (Almarro 318B). I've got a Signal DU-2 for my source.

The Signal DU series is a great isolation transformer. Wired in balance, it droped the noise floor substantially.
If anyone buys one off of ebay, PM me and I'll send you the wiring diagram for Isolation or balanced.

The DU-2 (2KVA) is plenty for sourse components in balanced mode. The DU-5 (5KVA) is plenty for high current amps in balanced mode.

If you check out my virtual system, you can get an idea on the box I've made to hide it. I used a Porter port for the outlet and a Furutech IEC for the inlet.
You don't have to use an IEC for the inlet, but it leave the option for rolling PC's.
jeff_jones
418 posts
 
Ngjockey - Am assuming you are referring to mechanical noise / 60 hz hum, which is a good point regardless of vendor choice. I.E. something to look out for.
I'm not sure why you think an oversized sola ('oversized' per other posts) would not provide excellent stability under dynamic load conditions?
ngjockey
1,042 posts
 
Wish it were that simple but there's more to those than just a transformer. As part of the ferroresonant design, they are partially saturated at all times. Along the same lines, in regulating voltage, amperage can suffer. So... with a dynamic load, they have to be oversized to a larger factor . While the CVT series has better amperage stability and tighter regulation, they're more like autoformers so noise reduction is one third of the MCR and a true isolation transformer.

Don't get me wrong, for decades they have been the 'king of the hill' as far as fast, reliable regulation and only recent, advanced electronic tap switchers can compete for the throne. They're also heavier and expensive, except for that used, $20, 1000W MCR portable I bought once.
jeff_jones
418 posts
 
Ngjockey - Thanks for the response.
I understand that the sola is not just a transformer:).
I'm curious about how incoming line harmonics would compare between a system with electronic tap switchers vs a sola system, maybe not an issue unless the o.p. went with multiple smaller units that could potentially be 'talking' to each other or had other sensitive non-stereo electronics on the same ac line. Perhaps not an issue at all but since the topic is about getting very nit picky with incoming ac it may be a nit worth picking.

Oh, for what it is worth I've never seen $20.00 per unit but I think you can find them reconditioned for about 50% price fairly regularly.
No response necessary unless the mood strikes you. Just pondering.
jea48
4,313 posts
 
I'm curious about how incoming line harmonics would compare between a system with electronic tap switchers vs a sola system, maybe not an issue unless the o.p. went with multiple smaller units that could potentially be 'talking' to each other or had other sensitive non-stereo electronics on the same ac line.
11-04-11: Jeff_jones

Jeff_jones,

Most of the odd harmonics found on the AC mains of our homes is from nonlinear loads connected to the mains within our homes. The home computer being one of the worst.

>http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/harmonics.pdf


>http://www.emersonnetworkpower.co.in/KnowledgeCenter/Whitepapers/K-FactorTransformer.pdf


Natan6355 is looking at a K rated 15 KVA transformer.

K rated transformers
>http://www.powertransformer.us/transformerarticles/transformerkfactorrating.htm


JMHO a 15 KVA transformer is overkill. He will have to feed that beast with #3 copper wire connected to a 2 pole 80 amp breaker, minimum, (125% of primary FLA). (240V single phase.)

Because there will be next to nothing of a connected load more than likely it will be mechanically noisy and very inefficient.....

A power utility pole transformer in older residential neighborhoods that feed 4 or more homes is only a 25 KVA transformer on avg. Pad mounts a 50 KVA on avg.
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