What Do You Guys Think About Balanced Power?

[mlucitt]

I was reviewing articles for power conditioners that use RF filters and isolation transformers the other day when this tidbit jumped out at me.

It seems that by using a 1:1 isolation transformer with a center tap on the secondary, you end up with 60V-0-60V. If you ground the CT, the 120V is split evenly across the hot and neutral legs instead of 120V on the hot leg and 0V on the neutral leg. The National Electrical Code (NEC) defines this as "Technical Power" and it is approved for use in recording studios and laboratories.

The idea is that because the two legs are out of phase they cancel the noise through common mode rejection. There are folks making boxes with 1KVA-2KVA (~10 Amp-20 Amp) CT transformers to run their audio gear power from and claim it makes a difference. As long as the equipment does not have the neutral leg of the power jack connected to ground, it should be OK.

One of the transformer is the Plitron 8575-X0-02 here:
http://shop.plitron.com/search_new.asp? ... ion=Search

What do you guys think of this?

Mark

 

[orange]

I was going to be a smarta%% and say if Italy is the question there is no answer

I really don't know.

 

[laatsch55]

Both Skratch and Gepetto run those units Mark.

 

[Gepetto]

I run a Topaz 2.5KVA Ultra Isolator transformer in balanced mode Mark. It makes a difference IMO.

It is a big time safety violation to have the neutral leg of the line tied to safety ground or to a chassis, be it internal or external. I hope no one has equipment such as that. UL listed Y caps are allowed for EMI filtering and surge suppression with a limit imposed on leakage current but not a direct connection. Long story short, most audio equipment is just fine on balanced power.

I highly recommend the Topaz, really built like a tank, is silent and the idle current is extremely low.

 

[Rex Everything]

I see it's not an inexpensive piece to add to your system.

 

[Gepetto]

The used marketplace has plenty of options...at reasonable prices. Check CL too.

 

[mlucitt]

I had a Topaz that absorbed a lightning strike. The board was fried beyond repair and I salvaged the 12V-0-12V transformer and some other parts. My understanding is the newer toroid transformers can be made almost totally hum free and that is what I am exploring. Idle current can be a factor with these isolation/balancing transformers because they usually stay on all the time.

What do you guys think about using a NTC 8 Amp, 2.5 Ohm, current limiting resistor/thermistor to reduce in-rush current for a 1KVA balancer? The circuit I am considering uses a CL-30 on the primary hot leg between the 8A fuse and the power switch, such as:

http://www.mouser.com/ProductDetail/GE- ... 0%252bFwrW" onclick="window.open(this.href);return false;

I don't see any downside using one of these devices.

Mark

 

[Gepetto]

Is this the Topaz you are looking at Mark? Mine is like this. Has no board or electronics involved. Just a huge, well constructed transformer with a very effective faraday shield between primary and secondary.[attachment=0:248c9bsb]Topaz.jpg[/attachment:248c9bsb]

 

[Gepetto]

It weighs about 80 pounds

 

[laatsch55]

Gotta love a man who loves heavy iron!!

 

[Gepetto]

It's nothing if it isn't heavy iron Lee.

 

[laatsch55]

Yep.

 

[orange]

I know that Balance Of Power was a really good yet underated Kansas album and their career was never the same afterward and then I don't know Jack about a hernia from that beastly boy.

Mein Gott!