which are the BEST toroids?

[Mecanp]

Hello guys.🙂 I m new here and have a question:
Me and a friend are to build a state-for-the-art PSU for his Krell preamp. currently we are trying to decide which toroid transformer to use,the specifications are:
Primary 220V frequency 50 hertz
Dual secondary voltage 30+30 V
Secondary current 5,5 A-330VA
Since its a Krell preamp in a high-end system, thus the highest quality is indispensable. We are between Hammond, Avel-Lindberg and Plintron
But which one is the best?😕
Thanks
PS.I m really interested in knowing what transformers the top companies (Mark Levinson,Classe,etc)use..

 

[Taco]

I think those companies let their trannies custom made with the specs they want. So I don't think that you can find completely the same transformers.

 

[Audiofanatic]

Hi and welcome,

As far as I know, some Krell preamp I'v repair are using Avel transformers.
I recomend Plitron, Not Plintron, I think that thats a combination of PLINIUS and PLITRON 🙄 😉

The sec. voltage will probably become a problem, cause they don't have (I think) the same sec. voltage as the Krell power supply you have.

Let us know the results in the end.

All the best AF.

 

[SDF]

Nuvotem talema toroids encapsulated transformers are good too, and they are not expensive parts

 

[Peter Daniel]

From what I know Plitron is building transformers for Classe, ML, Wadia, Bryston. They also have a stock 2 x 30V, 400VA toroid for about $70 CAD. Lead time is approx 4 weeks. Size: 4.7" x 2.7"

 

[Elso Kwak]

Hello guys.🙂 I m new here and have a question:
Me and a friend are to build a state-for-the-art PSU for his Krell preamp. currently we are trying to decide which toroid transformer to use,the specifications are:
But which one is the best?😕
Thanks
PS.I m really interested in knowing what transformers the top companies (Mark Levinson,Classe,etc)use..

Hi Mecanp,
You can do better than Krell et. al. by using a split bobbin or dual chamber transformer. The latter have much lower bandwith and let through less garbage from the mains. I am not impressed by the Krell powersupply. Not only do they use toroids but also do have no mainsfilter at all.
This whole issue is documented in the Audio Amateur (now Xpress) Magazine 1995 page 34 e.f. Regulators for High-performance Audio by Gary A. Galo.
I did a comparing listening test wih my preamp using a toroid and a split bobbin of the same voltage and wattage rating. It is not a day and night difference but the split bobbin is the clear winner!
😎 😎

 

[Peter Daniel]

Or maybe consider something like that: http://www.custommag.com/CMIHOME.HTG/rcore1.htm

 

[peranders]

I don't dare to say that Toriod International is the best (km!) but they make quite alright products. S.A.T (Swedish Audio Technology) and Advantage (Michael Bladelius) uses them and myself also.
http://www.toroid.se/
http://www.toroid.com/ american part
Special audio transformer http://www.elfa.se/elfa/produkter/se/20/2020471.htm

Notice the even winding!

 

[UrSv]

Or maybe consider something like that: http://www.custommag.com/CMIHOME.HTG/rcore1.htm

Or the same core from http://www.selectronic.fr/ which is in Europe/EU.

 

[Mecanp]

Thanks for the replies and info😎 .
..."Plintron, I think thats a combination of PLINIUS and PLITRON"....Nice one ! Yeah Plitron, since this Canadian factory is building transformers for Classe/Madrigal-ML then is the one for me,because IMO ML are the best SS amps in the world🙂 .

 

[jcarr]

I've used toroidals made by Plitron, and personally I liked the ones by Ulveco better.

As others have noted, the R-cores are quite good, too, the space efficiency factor will be better with a toroidal.

regards, jonathan carr

 

[Mats J]

Elso, or anyone else who may know...

Who makes split bobbin or dual chamber transformers? And of those manufacturers, who do you prefer?


TIA- Mats

 

[Peter Daniel]

Hammond is making split bobbin transformers, but they don't come in really big sizes. I got them mostly surplus or from Chinese store in my area. The biggest I've seen was 200VA.

 

[jcarr]

The R-cores _are_ dual bobbin designs. Faraday shields are also available upon request. See:

http://www.kitamura-kiden.co.jp/english/products_e.html

I've used hundreds of the R-cores in production with zero failures up to now.

Note that the above web page only mentions sizes up to 1100VA, but I believe that about a year and a half ago, Kitamura Kiden supplied us with either 1400 or 1500VA prototypes.

regards, jonathan carr

 

[Elso Kwak]

Split Bobbin Transformers

Hi MatsJ,
The Audio Amateur article (issue 4, 1995) recommended Signal Transformer. www.signaltransformer.com. The largest is 175 VA
I am using a Era from Germany
http://www.era.de/ie4_fs_produkte_e.htm These go till 30VA.
😎

 

[peranders]

I've used toroidals made by Plitron, and personally I liked the ones by Ulveco better.

Does Ulveco exist nowadays? Many many years ago Ulveco was bought (in Sweden) by Toroid Transformator AB if I'm not misstaken?

Ulveco bought Transduktor AB (logo hedgehog) and then when Toroid Transformator bought Ulveco they changed logó from a transformer to the hedgehog.

So if you like Toroid Transformator we have the same taste. They have also very high quality (electrical, mechanical). We by them at work and do our customers also.

 

[Eccu]

Just for info:
http://www.trafox.fi/eng_rengassydan/rs_english.htm

TF-model....
I use one Trafox transformer in my Crescendo...

 

[hifiZen]

I have to put in my vote for these trannies from Victoria Magnetics for Aleph-X. They came with a magnetic shield, which is normally an expensive option! The core is sized very conservatively, and the lead wire is very nice... I find the overall build quality much superior to the Plitrons I've used in the past.

 

[capslock]

Split bobbin, dual bobbin, dual chamber are all the same thing. It means that that primary and secondary don't sit on top of each other, reducing capacitive coupling.

You can have the same effect in a toroidal which has the windings on opposite ends but you don't see these too often (efficiency?). Or you can have an electric shield between the windings. www.schuro.de has epoxy sealed toroidals with an electric shield between primary and secondary and a magnetic shield on the outside.

 

[grataku]

My vote also goes to Victoria Magnetics. Well above plitron for options, quality AND speed. Five days from the time I oredered to the time I got two transformers.