R-cores are superior to toroidals in power supplies for low signal components, for power amps they're also limited by the available size.
Example of a preamp from 1998 with R-cores in the PS : SPHINX laboratories test project eight
(one transformer for each channel, a third for the peripherics)
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They seem to be better in stopping noise in the mains, as well as the classic 50 (or 60)Hz noise.
The one info I found on diyaudio is this one:
[...] R-core transformers usually have split-bobbin primary and secondary windings, which cuts down on interwinding capacitance and makes it considerably more difficult for non-50/60Hz noise components to pass in and out of the power supply. Additionally, R-cores have low levels of radiated magnetic flux and mechanical vibration, which allows them to be positioned closer to sensitive aplification circuitry without causing problems. [...]
from user "jcarr" on this thread: http://www.diyaudio.com/forums/parts/3019-where-can-found-r-core-transformer.html
I found other sources speaking positively about r-core transformers, but go find them again!
The one info I found on diyaudio is this one:
[...] R-core transformers usually have split-bobbin primary and secondary windings, which cuts down on interwinding capacitance and makes it considerably more difficult for non-50/60Hz noise components to pass in and out of the power supply. Additionally, R-cores have low levels of radiated magnetic flux and mechanical vibration, which allows them to be positioned closer to sensitive aplification circuitry without causing problems. [...]
from user "jcarr" on this thread: http://www.diyaudio.com/forums/parts/3019-where-can-found-r-core-transformer.html
I found other sources speaking positively about r-core transformers, but go find them again!
I think i could pickup a R-core transformer and compare it to my favourite potted toroid from Nuvotem/Talema.
This curiosity must be satisfied. For low power amplifiers (headphones or 2W max) they seem a valid option.
I can use ears and some basic measurements equipment - a 5,5 digits true rms DMM and a 50Mhz scope. If nothing else, this would be a good learning experience.
Edit: comparing with a screened and potted toroid would be interesting indeed.
These are the two transformers that I will be able to compare in the next few weeks, attached to AMB's sigma22 PSU:
1) http://it.rs-online.com/web/p/trasf...67573743D50312D322D3031384B2677633D424F544826
2) http://www.selectronic.fr/catalog/p...r-r-core-50va-avec-etrier/category/172666500/
Sorry for the long link from RS
This curiosity must be satisfied. For low power amplifiers (headphones or 2W max) they seem a valid option.
I can use ears and some basic measurements equipment - a 5,5 digits true rms DMM and a 50Mhz scope. If nothing else, this would be a good learning experience.
Edit: comparing with a screened and potted toroid would be interesting indeed.
These are the two transformers that I will be able to compare in the next few weeks, attached to AMB's sigma22 PSU:
1) http://it.rs-online.com/web/p/trasf...67573743D50312D322D3031384B2677633D424F544826
2) http://www.selectronic.fr/catalog/p...r-r-core-50va-avec-etrier/category/172666500/
Sorry for the long link from RS
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