[SET Man]

Hey!

   I'm in process of choosing a transformer and I can't make up my mind of which to buy.... 0-9V - 0-9V about 2A R-Core or Toroidal?

   So, just drop by here to get some opinion on this. Is there a big advantage in R-Core?

    I could get the toroidal of which will be about $20-25 cheaper with higher VA than the R-Core but if the R-Core is better than I'm willing to go for it.

   Anyone here have experience with both type?

Take care,
Buddy

PS

 If anyone know a good source for transformers of both type please let me know.

[JoshK]

R-cores have some theoretical advantages.  I am not experienced enough to know if it translates to practical differences.  I have bought some r-cores and my limited experience says they do not hum or get hot (could be I am not pushing them).

R-cores theoretically offer less capactive coupling between primary and secondary (less noise getting through) than toroids.  Offer better efficiency than EI cores.  Sort of most of the advantages of both without the penalties of both.

[Niteshade]

The person to ask is Boris of Vista Audio. He's the transformer guru. 

[Audiovista]

Haha, not sure about the guru thing (but thanks Blair!) - I do agree with Josh. However, I would not pay more than 10-15% premium for R cores. The power level Buddy needs seems too low for theory to translate into significant sonic advantage.

[rollo]

Check out the AudioNote site under articles about transformers.You have "E" core "H" core "R" core double "C" core.  They have a VG explanation of cores and materials for such. If it were me a double "C" core would do nicely.. Have fun.


charles

[rollo]

Giuseppe Bartolucci transformers as well. Double "C" core I believe Wytech uses them now instead of Audio note. Hope this helps

charles

[Occam]

The advantages of of R-cores over toroidal transformers (unless the toroidal has a shield between primary and secondary) regarding bandwidth and the passing of noise are quite real and measurable, and IMO, subjectively perceptable. But if you can provide power conditioning either externally, or internally within the component, there isn't a large difference.
My favorite transformers for source components are flatpacks, occasionally referred to as semi-toroids. Their cores shape is rectangular (better than a standard EI, but not as ideal as a toroid or r-core regarding EMI emissions), both r-core and flatpack transformers have physically separate bobbins which limit the bandwidth and transmission of noise.
I have a bunch of 24va, dual 10v secondary, Signal Transformer flatpacks LP-20-1200. and some dual 8v secondary versions LP-16-1500. If they'd meet your needs, you're welcome to 1 (or 2) gratis. PM me if interested.



http://www.signaltransformer.com/Data/Datasheets/LP.pdf
If you need more current, the 48va LP-20-2400 should meet your needs. Digikey has them in stock for $23 in singles. Signal Transformer is a very reputable, long established, Long Island based manufacturer.
http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=lp-20-2400

Regards,
Paul

[jtwrace]

http://www.magnequest.com/

[Turnandcough]

From my experience...For high current (amps) - torroid. For preamps, DACs etc - Rcore but a good EI will also do.

http://bryston.com/pdfs/news/84.pdf


 

[SET Man]

Haha, not sure about the guru thing (but thanks Blair!) - I do agree with Josh. However, I would not pay more than 10-15% premium for R cores. The power level Buddy needs seems too low for theory to translate into significant sonic advantage.

Hey!

   I see... thanks for the enlightenment on this transformer guru.

The advantages of of R-cores over toroidal transformers (unless the toroidal has a shield between primary and secondary) regarding bandwidth and the passing of noise are quite real and measurable, and IMO, subjectively perceptable. But if you can provide power conditioning either externally, or internally within the component, there isn't a large difference.
My favorite transformers for source components are flatpacks, occasionally referred to as semi-toroids. Their cores shape is rectangular (better than a standard EI, but not as ideal as a toroid or r-core regarding EMI emissions), both r-core and flatpack transformers have physically separate bobbins which limit the bandwidth and transmission of noise.
I have a bunch of 24va, dual 10v secondary, Signal Transformer flatpacks LP-20-1200. and some dual 8v secondary versions LP-16-1500. If they'd meet your needs, you're welcome to 1 (or 2) gratis. PM me if interested.



http://www.signaltransformer.com/Data/Datasheets/LP.pdf
If you need more current, the 48va LP-20-2400 should meet your needs. Digikey has them in stock for $23 in singles. Signal Transformer is a very reputable, long established, Long Island based manufacturer.
http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=lp-20-2400

Regards,
Paul

    Paul, you've got PM.... You just gave me the offer I can't refuse.

Take care,
Buddy

[art]

I assume that we are talking about a preamp, or similar application.

Go with the flat packs. Run the primaries in series. Cuts the VA in half, but probably not an issue.

Pat