Isolation Transformers

Boy some experts are missing the boat here!!

The isoloation transformers purpose serves (2) main purposes.

Voltage correction/protection and isolation of common mode noise..

Balanced power does not equally best esp on some regen units. Some line level gear designs do not like balanced power on because of their filter and grounding schemes.

yes an Arc welder DOES>> induce noise back thru the line and can cause some horrid THD problems .. sames as inverter duty drives in manufacturng plants!! I know.. seen it on a scope with TVA engineer... seen it disappear when 300 HP drive motor in a plant 6 miles away was shut down.. No air born RFI there!!

I live on the main power grid half way between (2) industrial parks 5 miles apart. I could not listen to my gear if it were not for iso transformers.

I have 3 types..
5kva 240/240 balanced for some of my amps
2.5 Kva 240/120 balanced for my Crown K2
both with faraday shields EI type

1kva 240/120 medical iso unit for line level gear.
1kva 120/120 medical iso unit for digital gear

http://www.geocities.com/jonrisch/index.htm

There are ONLY 2 reason transformers make any sound difference..

removal of common mode line noise.. quiter background

or compressed dynamics.. current limiting!!

You need to measure them for the lowest resistance per KVA load.. that means bigger wire..less copper more iron..
less current limiting..

Rule of thumb..unless you spec build a transformer for certain peak current demands ( my 2.5 kva unit will do 60 amp peak)size your transformer 2x the needed current load to prevent current limiting and do not use them on amplifier circuits.

Clio09,
Did you end up getting an isolation transformer? I discussed using a medical grade isolation transformer on another thread.

Sabai, I did try a Topaz unit and also tried the Exact Power unit recommended by Nagarch. I actually preferred the Exact Power. The isolation transformer actually was prone to mechanical noise. At the time I was living in a triplex in CA and the power fluctuated quite a bit from 110V to 118V. When my neighbor used her hair drier or turned on her AC unit the effects the transformer made lots of noise. Probably something getting injected back into the power line causing it.

These days I use products from Alan Maher Designs. I have been quite happy with them.

Clio09,
I am surprised to hear the neighbors affect your transformer. I have no such problems. My transformer emits a constant hum but the music drowns it out. The level of hum never changes. I bought it on Ebay. It is a high quality made-in-Germany non-balanced medical grade isolation transformer. I was hesitant to buy it because it is heavy and the shipping costs are expensive -- I live overseas. The moment I connected it I knew it was one of the most significant things I have ever done to improve the sound in my system -- a quantum leap.

Which Alan Maher products are you using?

Sabai, I was pretty surprised as well. The Topaz units come highly regarded and yes mine was heavy as well. I think they are fine units and my business partner and I have discussed building our own since he winds transformers. So I might give it another go.

For about 6 years now I have been using the Alan Maher PE's and CBF's. The PE's are plugged into various wall outlets and the CBF's are installed in my circuit breaker box. I also have one of his power strips with PE technology. The PE's provide power factor correction and line conditioning.