hi,
what about R-core transformers?
Googling around, not so many people uses them for PSUs although they seem to me what you'd go for in a high-end system.
Or am I totally wrong?
what about R-core transformers?
Googling around, not so many people uses them for PSUs although they seem to me what you'd go for in a high-end system.
Or am I totally wrong?
In reality it doesn't make that much difference if your power supply is well designed.
However, Toroids are good at passing HF noise from Primary to Secondary, an effect which is lessened in EI transformers.
Why R core - I don't know. I always use Toroids with a well designed PSU.
However, Toroids are good at passing HF noise from Primary to Secondary, an effect which is lessened in EI transformers.
Why R core - I don't know. I always use Toroids with a well designed PSU.
The way to find out would be to measure the frequency response and see which is better at cutting out high frequency noise.
I'm going to the P3A, a 60W on 8ohm amp from ESP, starting with a 500VA transformer (of some kind: toroid or r-core I still have to decide) 25-0-25. Have you got any suggestion for a PSU for such an amp?
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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I expect R-cores to filter out high frequency noise better than toroidals, but have never measured it myself.
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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