Variac vs. Isolation vs. Balanced Transformer? ALL
Undertow, 128V is pretty high. You must go through a lot of burned out light bulbs. Are you sure the volt meter you are using is giving you a correct reading of the voltage? Is the meter displaying true RMS or peak? I am looking to keep the system self contained and moveable vs. hardwired built in. I will have to take advantage of existing circuits for the time being. it You still could get by using one main isolation transformer and a small panel. Especially if your main electrical panel is in a basement and is exposed and easy to connect to. Of course you will need to hire an electrician to do the job. Install the transformer and new panel close to the existing panel. The electrician can easily move the existing audio branch circuits to the new panel. I would suggest buying a transformer with a 240V primary and 120V secondary. You may have to get one with a 120/240V secondary and just parallel the two secondary windings, 120V out. Here is the kicker though... You will need one more smaller transformer. This transformer will be a buck transformer connected between your main electrical panel and the primary winding of the main iso transformer. The buck transformer, (configured as an autotransformer), will lower your now 256V mains down to 240V. Balanced / isolation transformer It will have about a 5% loss bringing my wild voltage down to about 122, and in theory in turn give me 61 volts per phase on the output plenty low enough now being split into a balanced load for any gear to run much more optimally for the most part. Nothing fancy, nothing current limiting or adjustable just one continous clean output more or less regardless what the wall is doing, each leg will not vary much more than between 58 to 64 volts.........5% loss? Please explain the 5% loss. NEC 2005 Code Article 647. Same for 2008. http://www.equitech.com/support/647.html Note, the neutral is connected to ground. The 120V out for power use is two ungrounded hot conductors. . |
Jea48, I purchased a Balanced transformer that will be 60 - 60 v out
The 5% loss is supposedly just from going thru the transformer, it is a 1000 va size, and I am told by the manufacture there will be about a 5% loss in voltage essentially giving you a slight step down in the process. AS for light bulbs I have been using the ergo style flourescent newer curly Q looking type with no issue, but they have their own balast circuit built into the base which is why I think they cost more so this is probably why they don't burn the element as they are stepped way down from that internal ballast anyway unlike a cheapy 50 cent incandescent bulb. |
Undertow, you raise an interesting point about the relationship between line voltage and bias. I have high line at my house and its something I've taken into account when adjusting the bias of my amps. I don't understand though why gear should sound best between 115-118V when its designed to operate on 120V. In stock form, final bias readings would be set at the factory with line voltage held firmly at 120V, and obviously the amp should perform best at that voltage, not something lower. Regarding the balanced isolation transformer, I don't understand why you would get a 5% loss just from going through it unless it has been designed that way. I have worked with quite a few different isolation transformers of various brands over the past few years. All of them in stock form start out with some percentage of no-load boost, not loss. I have ordered transformers and specifically asked that they be wound without the boost, to compensate for the high line at my house. A decent, appropriately sized transformer with good regulation should not lose 5 percent under load. |
Gbart, well hopefully there is no loss! But for some reason there is a claim of up to like 5% maybe saturation or something with most transformers? Still it should be better due to obviously cutting the voltage in half on and spreading on 2 phases
As for sound in the lower voltage range they are not really designed to be on 120 from my understanding, but most is tested on the lower range of 110 - 115 v. However as for sound the higher voltage I believe adds certain noise at certain frequencys in the line. The U.S. standard for the most part is 120 volts, and the fact is they have to be able to spike to 130 I guess. No real scientific reason on my end this is just what I have normally experienced so some type of regulation beyond just saying okay whatever I am being fed from my garage on the circuit box is good enough seems a little off now having high grade power supplys in each audio component. |
