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Old 26th August 2003, 02:37 PM   #1
pooge is offline pooge  United States
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Default Balanced isolation transformer offer

If you are considering going the symmetrical power route, check here for a deal on a wholesale buy for a 2000VA Plitron balanced isolation transformer for $250. Looks like a really good deal. Haven't yet found out if the secondaries are capacitively balanced, though, which is key to having this concept work effectively.

http://www.hometheaterhifi.com/volum...er-8-2003.html

Apparently, a power buy can reduce the price even further. Anyone interested in trying to do this?
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Old 26th August 2003, 03:37 PM   #2
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You can buy a 1500 VA toroid from Plitron for about $100 less.

I'm sure that the secondaries are a bifilar winding.

Jocko
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Old 26th August 2003, 04:06 PM   #3
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Hi,

Beware of toriodal transformers of that size. The large inrush current will for sure blow you fuses. You need an inrush current limiter for those beasts.

Btw. Bought last year a military 240V/240V/120V - 2KVA toriodal isolation x-former for 25 EU from a dump store. Complete with casing, cables and sockets. But no way to switch it on without inrush current limiting.

Cheers
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Old 27th August 2003, 12:50 AM   #4
pooge is offline pooge  United States
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Well, if bought in ten, the price drops to $205. Still haven't found out if the secondaries are capacitively balanced. Further, they specify 115V inputs. I have 125V at my house. This would put the output up to 130V.

It is curious, though, why their Medical Isolation Type 1 transformer of the same rating costs less, when they have an outside case for a magnetic shield and thermal fuses. They just don't come in 60/60 secondaries. I am told that they are bifilar wound, though. Not sure that this alone will give you capacitively balanced secondaries. Further, if the standard line is bifilar wound, but lacks only an electrostatic shield, the price difference is questionable. I'm told that I can order an electrostatic shield with a standard, but their web site makes it sound like that would have to be a custom order, which requires a minimum of ten units.

I wrote Plitron and asked about the Secrets transformer. I ask if the secondaries were capacitively balanced. Par for the course, I got an answer to a different question. Communication isn't their strong suit.

I haven't got a straight answer yet about their balanced transformers.
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Old 27th August 2003, 01:55 AM   #5
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Basicaly, everything you order from Plitron is regarded as special order as they make transformers after you order and you wait approx. 4 weeks.

You can order a single transformer with whatever features you wish. The price is usually as quoted on the list, plus additional fees for extras, which are not really that high. I don't see any special deal in the initial offer. If you need any specific information from Plitron, I can call them tomorrow.

BTW, I tried the LONO transformer (1.5K VA) with balanced power setup and didn't like it on my source equipment.
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Old 16th April 2012, 12:29 PM   #6
Legis is offline Legis  Finland
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Interesting old thread.

I have used normally wounded 3000VA balanced isolation transformer for two years and have really liked it's sound. Better micro resolution, less grain and edge and bass seems to be more in control because the supply voltage is much better regulated than straight from my mains. Mains are usually 227V but the trafo still outputs 230V and the voltage stays more constant under constantly variying load of the loudly played music. The trafo acts as a regulating local power bank for the equipment. The trafo adds little to the output impedance of the mains of course but I'm countering this by upgrading to the 5000VA trafo soon, which I think will give even better regulation and power reservoir.


Regarding the winding style and the capacitance the trafo:

I have tried to minimize the capacitance of my mains by using teflon insulation, loose braiding, and decided to drop the shielding after many years of using only shielded cables. The result were biggest improvement that I had never heard between shielded, high capacitance cables, wether they vere several kilo euros commercial cables or DIY.

I also tried so called "parallel AC-filter" with 5 stage CRC filter and also with bare 17,5F 500Vac polypropylene capacitor between the windings (X-capacitor). The big capacitor killed the sound totally, the effect was very pronounced for some reason. I decided to drop both filters and also removed couple of regular 0,1F X-capacitors that were in the equipment by default.

Based on these experiences, I would be quite hesitant to get bifilarly wounded instead of normally wounded transformer, because of the added capacitance. It's just a hunch, I have never tried them both unfourtunately.


Peter Daniel, if you are reading this do you rememeber why you did not like the sound with the trafo, and do you know how the secondaries were wounded? Have you taken another punch into the isolation transformers during this passed time?


Regards,

Legis

Last edited by Legis; 16th April 2012 at 12:37 PM.
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