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Old 4th November 2004, 01:03 AM   #11
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Quote:
Originally posted by Andrewbee
Its not shaped like an "R". the shape is somewhat / kind of/ somewhat like a rectangle but with rounded ends. The "R" stands for racecourse as in horse racing, that is what they use to describe the shape. If you go the link Planet 10 posted you will see them. I bought a pair of the single end RW-20's soon after they first came out.

AB

Thanx AB. I always just assumed those were double C-cores, since you don't see what is in the middle where the wire is wound. No band clamp though. It never occured to me. I don't own any of these so I didn't have a hands on model to study.
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Old 4th November 2004, 12:58 PM   #12
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Question Power Transformers

Hello Jonathan, I am aware of all that information in your post.
I compared a 30 Watt toroid from Amplimo with a dual chamber 30Watt from Era in my DAC and preamp, three years ago. The split bobbin is always giving better sound.
www.amplimo.nl
www.era.de
My interest in transformers is revived as I noted a substantial improvement in sound when I placed a second 30Watt transformer parallel to the original one. I am really puzzled by this result as my DAC does not draw very much current; I guess something like +/-250mA. I have 1 Ohm resistors in series with the secondaries as in Jim Hagerman's schematic for the bugle power supply.
http://www.hagtech.com/images/powersupply.gif
So before ordering a 330Watt EI-core I was curious how much difference a R-core would make.
I also noted a higher DC resistance in the secondary for a 50 Watt toroid from Sedlbauer compared with a 30 Watt dual chamber from Era.
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Old 4th November 2004, 01:04 PM   #13
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Lightbulb Advantages of R-core trannsformers

Quote:
Originally posted by tubetvr
Hi,

What are the advantages, (from an users perspective) with using a R-core transformer compared to a C-core? For me they look very similar although I can understand that there are advantages from a mass production perspective i.e. no need to cut the core, polishing the ends and clamp the whole thing together.

Regards Hans
Hi Hans,
You can find the advantages here:
www.jeichicago.com/products/r-core.shtml
www.jeichicago.com/products/r-core_compare.shtml
But the question is what is the effect on the sound.
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Old 4th November 2004, 04:46 PM   #14
jcarr is offline jcarr  United States
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>Hello Jonathan, I am aware of all that information in your post.<

In that case, Elso, why didn't you state what type of information that you looking for, instead of asking a horribly vague question that could be interpreted in half a dozen different ways?

As it is, writing a response to your question appears to have been a total waste of time. I will try not to make that mistake again in the future.

jonathan carr
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Old 4th November 2004, 04:54 PM   #15
Cobra2 is online now Cobra2  Norway
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Default R-core !

Quote:
Originally posted by jcarr
>Hello Jonathan, I am aware of all that information in your post.<
As it is, writing a response to your question appears to have been a total waste of time. I will try not to make that mistake again in the future.

jonathan carr

It was however useful for others...

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Old 5th November 2004, 07:08 PM   #16
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Hi!

As for the comparison between a normal toroid and an R-Core, I can only say that I substituted a 300 VA 30 - 0 - 30 toroid for a 360 VA 33 - 0 - 33 and 36 - 0 - 36 R-core on a mono LC The End Millenium.
The 33 V, 330 VA windings driving the amp circuit, stabilized by 4 * 20.000 uF (63V) caps, and the 36 V, 30 VA windings driving the voltage amplifier and the driver stage, sabilized by 8 * 1000 uF (63V) caps.

In comparison, what is most evident is that there is no hum or vibration whatsoever (the cheap toroid was slightly humming and vibrating, only when you tourched it or put your ear near it).
Also there is no power-on thump (and I have no protection circuitry or resistors before the R-core).

If the sound is better, I can not really tell. But then I am also not able to tell the difference between a GC built with LM 3875, LM 3876, OPA 544, OPA 541 and OPA 549...

All I can say that the amp has enough power for my diy 15", 120l subwoofer which weights 67 kg...

I would say that an R-core should at least be considered for high end applications which do not need loads of power, like pre-amps or DACs... Which is exactly what for example Sony uses them for...


Bye,


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Old 6th November 2004, 06:14 PM   #17
Steven is offline Steven  Netherlands
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R-core in Europe (also O-core):
http://www.feickert.de/Transformator...re/r-core.html
http://www.feickert.de/Transformator...re/o-core.html

Steven
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Old 6th November 2004, 06:38 PM   #18
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Quote:
Originally posted by Steven
R-core in Europe (also O-core):
http://www.feickert.de/Transformator...re/r-core.html
http://www.feickert.de/Transformator...re/o-core.html

Steven
Hi Steven,
yes I know but Dr. Feickert declines to respond to my email.
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Old 6th November 2004, 10:26 PM   #19
Steven is offline Steven  Netherlands
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Quote:
Originally posted by Elso Kwak


Hi Steven,
yes I know but Dr. Feickert declines to respond to my email.

It's a shame.
I just picked up this link in some thread; can't remember which one (maybe UCD180). I never bought something from him.

Steven
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Old 28th March 2005, 07:33 AM   #20
dcf is offline dcf  Germany
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Hi folks,

as I am about to terminate the old cooperation with my former partner I have to clear the stock. As for Elso's transformers it is a nightmare. Sorry Elso for not having come back in time....

If anyone has a special interest in those transformers please let me know

Cheers,

Chris
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