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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
jeff_jones
418 posts
 
Dan-ed - All connections back to and inside the incoming ac panel have been verified for tightness? Wire routing is according to hoyle, etc.? I suspect that you have checked all the basics but, just in case.

The weirdest hum issue I've had (2 arcam alpha 10's, 1 would hum whenever plugged in the other 1 never hummed, nothing else plugged in to the same circuit showed any sign of a problem) went away for good when I tightened all neutral connections at my incoming breaker panel. At least I assume it was due to a neutral connection because no other connections seemed suspect. Arcam's tech said on the phone that it was an ongoing frustration for him at the time, some units would hum at customers site but not hum in shop, some units would not hum.

jea48
2,944 posts
 
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.
11-07-11: Dan_ed
Dan the polarity orientation check is only a test to make sure the manufacture of the amp checked for proper polarity orientation of the primary winding of the transformer before it was wired to the circuit.

If the test shows one of the amps power transformers has reversed polarity the next step is to check the power cord, if detachable IEC connection, and make sure the polarity of the cord is correct. Especially in the case of an aftermarket non UL or CSA listed power cord.

Next step if the power cord/s checks ok and the problem is the amp I would then try a real word test of the system and check for the ground loop hum.

Remove the ground cheater on the good amp. For the test the amp that needs the polarity reversed install the ground cheater into the wall outlet that gives the lowest voltage reading of the two.

Next connect the ground of the cheater to earth ground. (equipment ground at the wall outlet).

Turn system on and check for hum. IF hum is gone then the next step is to correct the problem.
The correct procedure is to reverse the primary leads connection inside the amp. Who better to do the job than the manufacture. Good chance he will only charge you for shipping.

You could also take the amp to a reputable repair tech.

There is no guarantee the hum problem is caused by a polarity reversed orientation. The test will require a little of your time and hopefully find the problem.

Or you could just buy a Jensen isolator for one or both ics.
Contact Jensen, bet they would be glad to help.
Jim
jea48
2,944 posts
 
Perhaps Jim or Al can comment on the issue of UL/CSA standards and shunting/grounding as compared to IEC.
Ngjockey

Ngjockey,

Could you please expand on your question.

I am no expert on UL, just know the basics.

UL like NEC code is bare minimum safety standards.
And in the case of Dan's hum problem as long as the amps are safe to use UL or NEC could care less how they sound.

In fact, if memory serves me right, any current leakage below 5ma is acceptable.
.
dan_ed
2,451 posts
 
The cost of the jensens and the fact that they will impact the sound doesn't make that an attractive long-term solution. I guess I'll just byte the bullet and send these off to get fixed the right the way. Can't blame a guy for trying to find an easier solution, but in the long run, there is only one way to fix this correctly.

I know my guy can fix this since he's been marketing his own monoblocks for a year now. He'll be shocked I'm finally sending these amps to him since he's been after me for a while now. :-)
almarg's avatar
almarg
8,673 posts
 
For the record, I just noticed what appears to be a boo boo in the paper by Mr. Whitlock of Jensen Transformers.

In figure 2, which I referred to earlier, the formulas for Vx and Vy should have CPS1 and CPS3 in their numerators, respectively, rather than CPS2 and CPS4. That follows from the fact that the voltage divider effect between the two capacitances in each component will be dependent on the reactance of the capacitors (1/(2piFC)), not on the capacitance values themselves.

Therefore I retract my previous theory about CPS4 of the unused amplifier causing Vy, and hence the hum level, to worsen.

Best regards,
-- Al
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