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.
Thanks for your interpretation. I believe I have the "extremely rare" occurrence mentioned in the Jensen paper. :-) I realize this probably won't eliminate all of the hum, but cutting it in half might make it liveable. I'd like to put each of these two amps on their own balanced supply. These are around 60 watt PP amps so I don't need too large of transformers. Maybe a pair of 500va on each. Finding them for an experimenting price might take some looking.
See the second paragraph of page 2 of this Jensen paper. A key factor in how much hum reduction would result is the stray capacitance within each component between each of the two ac input lines and chassis, particularly stray capacitance in the power transformers of the components, and how similar or dissimilar those stray capacitances happen to be. So while I would expect there to be SOME improvement, the amount of improvement figures to not have a great deal of predictability.
11-06-11: Almarg

My thinking as well.


I took some measurements from each amp using the ground tab on a cheater plug with nothing turned on, just plugged in. I'm seeing 16 vac on the ground tab from one tube amp and 14 vac on the ground tab with the other tube amp. The SS amp shows no potential. I didn't bother measuring the ac current.
11-06-11: Dan_ed


If you are checking for the proper AC polarity orientation of the primary winding of each amp's power transformer nothing can be connected to the input of the amp/s. Also equipment ground of the amp/s has to float. (Amp is isolated)

The ground cheater you use needs to be the non polarized plug type or you will need to trim down the wider blade so you can reverse the plug in either direction.

The lower measured voltage reading is the correct polarity orientation.

Post back your results.
Nothing about the Equitech article implies any kind of panacea. In fact, if it's a ground issue, even separately isolating each amp might not help.

Perhaps Jim or Al can comment on the issue of UL/CSA standards and shunting/grounding as compared to IEC. I gotta step back and listen when those guys are talking.
Perhaps Jim or Al can comment on the issue of UL/CSA standards and shunting/grounding as compared to IEC. I gotta step back and listen when those guys are talking.
Thanks for the compliment, NG, but those kinds of standards are not among my areas of expertise. Jim?

Best regards,
-- Al
Thanks for the help, guys. Jea48, even if I did that it can't be maintained with a three prong connector. Yeah, the best solution would be to pack them off and have them rewired to play together. I hate shipping them as one already has chassis damage from mishandling.