Yes I know, old thread but I have found a site: R core transformer_James transformer-custom toroidal transformer|R core transformer|O core transformer|C core transformer|EI transformer
That's not in Europe unfortunately. It also has the more rare O-core transformers
The thing is that their r-core transformers seem like chinese-with-new-sticker to me. Anybody with some experience with them ?
Anybody with experience with the companys o-core transformers?
or any recommendations for other suppliers of o-cores? - as well as general impressions of the o-core performance compared to other transformers.
or any recommendations for other suppliers of o-cores? - as well as general impressions of the o-core performance compared to other transformers.
R-core is available direct from Kitamura kiden, the inventor of R-core trafo. They do sell direct, just email from their website. Shipping via DHL/Fedex only, no EMS.
It cost an arm and a leg, which turned me away when choosing trafo for my project. Another is Shimizu denki but only up to 320VA, never contacted them.
Supposedly they use top quality material.
It cost an arm and a leg, which turned me away when choosing trafo for my project. Another is Shimizu denki but only up to 320VA, never contacted them.
Supposedly they use top quality material.
Expensive in electronic is a strange yard stick, a chip to 50 cent can be called expensive while an other 200$ chip can be called a bargain.
Do you have an example on a price, nothing you have to guarantee but just so I know how much of my arm I have to cut off🙂
In a way, it may not be so strange that the transformer is expensive, it is the inventor, the one who know and put his name on how it is done. So it have to be the best.
Kitamura 400VA is around $500 incl shipping + 27.5% import tax. I find it hard to justify the cost. In the end I just get a toroid about 40% of that price. Even that is way more than what people are paying for Antek toroid.
I understand the Japanese mentality of "shokunin" its a little bit of artisanal spirit in a sense. They just want to build something of the best quality stuff according to them.
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WOW that was steep, is it made of pure gold? 🙂
Okay, if you are building a reference "don't care about the price" amplifier that would cost 50,000$ in sale, the transformer is a no brainier.
But how much is the R-core better?
@FriedMule, correct question is which are advantages of R-Core versus other transformers and these are:
- high efficiency,
- low noise,
- low loss
- low flux leakage,
- no-load current
R-Core transformers make sense in ultra low noise applications, low jitter clock, mc phono etc.
Regards,
Tibi
- high efficiency,
- low noise,
- low loss
- low flux leakage,
- no-load current
R-Core transformers make sense in ultra low noise applications, low jitter clock, mc phono etc.
Regards,
Tibi
An R-core transformer is an uncut C-core, so what's the big deal?
No air gap due to C-core cutting, so higher permeability of the core. But lower resistance to DC currents.
No air gap due to C-core cutting, so higher permeability of the core. But lower resistance to DC currents.
they are like toroids for DC currents super sensitive,
They can be CUT with a gap too, so don't be too fast to judge.
Advantage over Toroids: they can be winded in perfect symmetry with computer controlled winding machines.
I use computer controlled winded up R-cores
They can be CUT with a gap too, so don't be too fast to judge.
Advantage over Toroids: they can be winded in perfect symmetry with computer controlled winding machines.
I use computer controlled winded up R-cores
That's not special: all transformers using straight bobbins can be wound with computer controlled winding machines to maintain symmetry. That's normal practice nowadays.
A not unimportant property of R-cores is that the bobbins are round.
Winding round bobbins can be done faster (economics....).
Just check an R-core transformer closely and you will see that the bobbins are wound with special winding equipment because the bobbins are already mounted on the core when wound.
When R-cores use cut cores, I don't see any advantage of them over c-core transformers.
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As I understand it, you are right. No matter how perfect you wind the cobber, it will always be tighter on the small diameter hole, then the outer diameter, resulting in difference between how the flux and heat are on the torrid.
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