Kind of funny that you bring this up, as I was discussing this with a local shop today. Your dealer is talking about an isolation transformer and he is right on the money. There are a couple of different designs for isolation transformers though with some working better than others. Most any of them would work well for what you want it for so long as it could pass enough current. That is one thing to consider with amps for sure. As to using them for sources and preamps, etc... the ideal set-up would be a properly sized transformer for each component. I may try doing something like this sometime shortly.
My experience is that "old school" iron core transformers work better than "high tech" toroidals in isolating noise, so that would be an easy thing to check. Sean
As usual, Sean's comments are correct. You must choose a device that is capable of delivering the current that your components require.
There are some other considerations. A normal transformer is not a voltage regulator. If the input goes up or down, the output follows along. If the device your dealer is selling does indeed maintain a constant output voltage then it is more complex than just a transformer.
As for building your own, that is relatively simple IF you know what you are doing. You are dealing with line voltage here and an improperly designed conditioner could easily be a fire and/or an electrical shock hazard.
One of the big advantage of some of these isolation devices is that they convert your AC from unbalanced to balanced. This can potentially greatly reduce the amount of noise and hum in your system.
A transformer is also not an ideal isolation device. If it were then you would not need an extra one since every amp, preamp, etc. that you have already has a transformer in it. Since a transformer does not completely isolate your components, they usually contain contain surge suppressors and noise filters so getting a box and a transformer would not be the same as buying one of these units. Devices such as the MIT ISO have filters to keep noise from entering or leaving.
As with all things in this hobby, the only way to tell if a particular device will benefit your system is to try it.
I built my own power supply using (as mentioned above) a toroidal transformer and dropping a 230V line down to 115 with 2 balanced poles. It was a great improvement. Equi-Tech makes these types of devices. I will likely use there's in the future as the transformer is likely better than the one I used.
Sean has some very valid points about Isolation transformers. due to the fact that your Digital gear produces the most noise in your system it's crucial that they be isolated from your Analog gear. Ensemble of Switzerland has been building special isolation transformers specifically for this purpose for over 10 years now, and have perfected their use for Digital audio in their latest designs. keep you Amp plugged directly to the wall where it can draw all the current it needs. once your digital gear is cleaned up and unable to contaminate your Analog then you won't have to worry about filtering your amplifier. also we have tried ballanced power devices such as the Equi-tech and found them to do more harm than good. ballanced power devices can also be dangerous and if i'm not mistaken will soon be banned for sale in the US.
Artistic audio: Can you be more specific about the dangers of balance power supplies? I used one for several years and was very happy with the sonic improvements. The transformer was rated at 6.5 kAV, so it was up to the task. Is the problem with the balanced poles going into the equipment--is the equipment not designed to handle power like this. As I said, my sonic results were fantastic, and I didn't have any of the current restrictions that I found (particularly for my amplifiers) with all other power conditioners I tried. I have not tried Ensemble. Perhaps you have more information on their unit--are you a dealer for them by chance?
In responce to Rives Audio about ballanced power devices, you may want to contact Equi-Tech directly to find out why ballanced power conditioners are at risk to the consumer. I have heard that they will be banned soon due to electrical shock hazzards. personally I have compared the Equi-Tech units to the Ensemble & Richard Gray and found much better results with the latter. to answer your question, Yes I import the Ensemble line from Switzerland. you can find out more information at: http://aaudio.com/ensemble.html
I'm glad to see interest in this topic. Have any of you sourced balanced transformers? I like good sound but don't like the high $ to get it. I have heard the Richard Grey unit and that sound is what I am after.
Truthrider: They are expensive. The one I used was an engineering unit for a medical device that was no longer needed, so I got it for free. Finding 6.5 kAV units are not easy and they are expensive--as are the Equitech units. I did also contact (by e-mail) Equitech and let them know that it has been reported here that their devices may be a serious safety hazard and are likley to be banned in the US. I am hoping they will respond, as I have spoken to the engineers there before and they have boasted about their UL listing. It makes these claims of safety hazard and likely banned in the US hard to believe, but we will see what they have to say about it.
We have used a isolation transformer for years. We use a standard line no current limiting conditioner for amps, pre. Isolation transformers for all digital. My HDTV for that matter. The differences with and without isolation transformers is staggering. We actually plug our isolation devices into our line conditioner for even greater improvement. The tonal qualities, soundstage, blacker blacks etc. is all improved using these devices. We do not use the balanced type so I'm not sure as to the safety issues mentioned above.
I find myself commenting here on a rumor that balanced power is on its way out in the US.
This is patent nonsense.
In 1996, Article 530 Part "G" was adopted in the National Electrical Code by the members of Technical Panel #15 which includes representation from literally every segment of the electrical industry including electrical inspectors, chief electrical engineers of large corporations such as Universal Studios, manufacturers, IBEW Union representatives and a host of other electrical authorities.
In the most recent edition of the 2002 National Electrical Code, Article 530 Part "G" was superceded by a new article dedicated soly to the implementation of balanced power. The committee felt that its place deserved an article of its own in the codebook. That would be Article 647. The primary difference between the former text and the current version is that the scope of balanced power has been widened to include ANY sensitive electronic apparatus, not only sound and video equipment.
This doesn't sound to me like anyone is going to ban anything. Rather, it is quickly becoming the electrical industry standard for applying power to sensitive electronics of any type.
I hope this straightens out any confusion.
Thanks for the space.
President, Equi=Tech Corporation
Author Article 530 Part "G" 1996, 1999 NEC
Author Article 647 2002 NEC
Rives: 6.5 KVA ??? Now THAT is a transformer. Only problem is that you'd need one HELLUVA circuit feeding it in order to tax its' capabilities : )
Martin: Thanks for responding. While we've got you here, can you clarify something for me ? If a noise source is generating interference into both sides of the AC line in equal amplitude and phase, will "going balanced" filter that out ? I think i already know the answer but would like to get input from someone that specializes in this field. Sean
Sean: As I said it was for a medical device (an x-ray unit). This is actually a small transformer for an x-ray unit. I did use a 220 v 30 amp line to feed into it and then had 110 v with four separate circuits and filters. 2 were 15 amp and 2 were 20 amp. Obviously, the equipment did not draw all that or it would have caused the 220 v 30 amp circuit breaker to go.
I have a 1KVA low-tech coil isolation transformer, weighted 35 lbs.
My experience is that the IT does expand the soundstage and helps the seperation of instrument. The bass can reach lower and highs are significantly smoother on my system. The overall sound is certainly clean and pleasant.
The only drawback I found on traditional IT is the slow response. When I watch those booming movies such as "Pearl Harbor" , I notice the bomb's full explosion was just a bit staggered than usually. This may be due to the fact that the transformer need a bit more time to 'transform' large power from the input to the output.
My amp consumes about 400W and the 1kVA transformer should be well beyond the amp's quest for power, but it does not seem that way.
Now I unplug the IT when I watch movies and put it back when I listen to strings and vocals.
Isolation transformers should have a 20:1 ratio to work properly which is why we generally recommend them for digital components, televisions or pre's. As an example your IT should be rated at 8kVA to avoid transformer saturation. I may be in overkill mode but, better safe than losing dynamics.
Jc, how did you arrive at the ratio that you posted ? As to being "overkill", i like that : ) Sean
JC is right to a large degree. With most transformers the inductive process (which is how the transformer works) also works against it. It can, if not designed properly, limit the current flow. This is a big deal in x-ray devices as they require HUGE amounts of current flow on demand, and they are always pushed right at their limit. If it's a 6.5 KVA unit, you can bet the demands are at least 6 KVA. Many of the transformers that we find in some products are off the shelf transformers that really don't serve audio very well--particularly amplifiers, which is why so many amplifiers sound better not connected through an isolation transformer (power conditioner).
As to a 20:1 ratio--I don't know about that, but I would definitely agree with an abosulte minimum of 5:1 for amplifiers unless it was really designed to deliver the current on demand.
The 20:1 ratio was the number used by the company that manufactures the ISO isolation device in order to prevent transformer saturation. This of course had a large margin of safety in it.
I find these comments about balanced power systems as being possibly banned in the u.s. and dangerous utterly irresponsible. To have them come from apparantly audio professionals who sell competing products is disgusting. It is one thing for unknowlegeable end users to spout off about something and another, but for someone in the business with access to a wealth of information to throw out this trash is disgusting.
I am not in the business, and recently built a new dedicated theater as well as secondary audio video areas in my home. After reading the highly informative series in Widescreen Review regarding the construction of its audio video testing room I looked into equi-tech for my system. WR used this supposedly dangerous about to be banned Equipment in their system and who would think they know anything? I don't accept as gospel what I read in these various magazines keeping in mind they get advertising money, but anyone on these threads can go to their web site and read for themselves.
The equi-tech stuff is used in recording studios throughout the country and the results in my system has been fantastic. I purchased a wall panel which provides power to my media room,a living room a/v system, and my whole house distributed products. The bang for the buck is enormous. No surge protection required and no other devices such as Richard Gray. I tried the gray product and it was bad for the audio and added nothing to the video. WR like the gray equip for some applications. Sound and video are noticeably better. I had a plasma tv which was like a new piece of equip. when plugged into the equi-tech. Startling detail,color, and depth.
Anyone can like or not like this or other equipment, but to proliferate bull about a product that is UL approved and covered by the National Electrical Code is unacceptable.
I would guess that your isolation transformer is not big enough for that much current draw. Note my previous thread about the ratio. Even if 20:1 is overkill I think your running into transformer saturation. We usually prefer these devices on digital and sometimes pre-amps and small televisions. Digital being the most important