PSU transformer search

ChocoHolic · 7th August 2005, 09:37 PM

Hi Ho... !
I am looking for a rather specific transformer.
The power rating should be 250VA ...350VA.
The primary should be splitted in two windings in order
to allow 120V and 230V as well.
The secondary should be in the range of 9V..10V nominal.
2x9V or 2x10V would be also fine as long as the windings
are NOT connected/centertapped and allow paralleling.
And there is a big MUST: It has to be suited for safety class II
applications.

...I could accept an E-core or torroid as well...

I would be glad about any specific hint or indication of
shops in Europe that generally sell such transformers.
Special HiFi component shops would be also fine.

Thanks in advance
Markus

AudioWizard · 7th August 2005, 10:26 PM

May I suggest an R-type transformer instead of toroidal?

You can find 300VA/2x9V ones.

moamps · 7th August 2005, 10:28 PM

Did you check here?
http://www.tauscher-transformatoren.de

Regards,
Milan

ChocoHolic · 8th August 2005, 07:07 PM

Thanks !
Tauscher is looking promising. They do not mention "Schutzklasse II"
on a single site... But most of their transformers have the symbol for reinforced isolation. Fine.

R-type transformers... quite exotic...
....like double aperture designs...
They probably have a low leakage inductance and by this
they will probably offer a low output impedance.
But I feel the fundamental construction will make good
isolation more difficult for the manufacturer.
Do you know a good vendor?

AudioWizard · 8th August 2005, 10:58 PM

Quote:

Originally posted by ChocoHolic

R-type transformers... quite exotic...
....like double aperture designs...
They probably have a low leakage inductance and by this
they will probably offer a low output impedance.
But I feel the fundamental construction will make good
isolation more difficult for the manufacturer.
Do you know a good vendor?

Well, in France you can find those here: Selectronic

not sure if they sell outside of France, but it's likely.

Those transformers are still kinda hard to find, but they look very promising from what I've heard.

jmateus · 8th August 2005, 11:31 PM

Do you guys know any vendor in the USA?

ChocoHolic · 9th August 2005, 11:31 PM

uhps...!
When looking to this R-Types, at first glance it looked like an double aperture... BUT it is the other way round !
The iron is shaped like a double U and the windings seem to be positioned on the opposite legs...
That's good for isolation, good for low capacitive feedthrough...
but would theoretically also give a higher leakage inductance and with this higher impedance.... which is in contradiction to their statement..

Hm... or do they wind splitted prim and sec on each leg?

AudioWizard · 9th August 2005, 11:37 PM

ChocoHolic,

a little more info here.

By the way, looking up "r-core transformers" instead of "r-type" may help you locate more vendors/resellers.

ChocoHolic · 10th August 2005, 09:30 PM

...thanks!
hm... definitely not matching to what I would
have expected. But quite interesting!

7th August 2005, 09:37 PM	#1
ChocoHolic diyAudio Member Join Date: Dec 2003 Location: Munich	PSU transformer search Hi Ho... ! I am looking for a rather specific transformer. The power rating should be 250VA ...350VA. The primary should be splitted in two windings in order to allow 120V and 230V as well. The secondary should be in the range of 9V..10V nominal. 2x9V or 2x10V would be also fine as long as the windings are NOT connected/centertapped and allow paralleling. And there is a big MUST: It has to be suited for safety class II applications. ...I could accept an E-core or torroid as well... I would be glad about any specific hint or indication of shops in Europe that generally sell such transformers. Special HiFi component shops would be also fine. Thanks in advance Markus

8th August 2005, 11:31 PM	#6
jmateus diyAudio Member Join Date: Mar 2003 Location: US, New Jersey	R trafos Do you guys know any vendor in the USA? __________________ JLH 2005, Cyrus and so on...

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7th August 2005, 10:26 PM	#2
AudioWizard diyAudio Member Join Date: Feb 2005 Location: Southern France	May I suggest an R-type transformer instead of toroidal? You can find 300VA/2x9V ones.

7th August 2005, 10:28 PM	#3
moamps diyAudio Member Join Date: Oct 2002 Location: Croatia	Did you check here? http://www.tauscher-transformatoren.de Regards, Milan

8th August 2005, 07:07 PM	#4
ChocoHolic diyAudio Member Join Date: Dec 2003 Location: Munich	Thanks ! Tauscher is looking promising. They do not mention "Schutzklasse II" on a single site... But most of their transformers have the symbol for reinforced isolation. Fine. R-type transformers... quite exotic... ....like double aperture designs... They probably have a low leakage inductance and by this they will probably offer a low output impedance. But I feel the fundamental construction will make good isolation more difficult for the manufacturer. Do you know a good vendor?

9th August 2005, 11:31 PM	#7
ChocoHolic diyAudio Member Join Date: Dec 2003 Location: Munich	uhps...! When looking to this R-Types, at first glance it looked like an double aperture... BUT it is the other way round ! The iron is shaped like a double U and the windings seem to be positioned on the opposite legs... That's good for isolation, good for low capacitive feedthrough... but would theoretically also give a higher leakage inductance and with this higher impedance.... which is in contradiction to their statement.. Hm... or do they wind splitted prim and sec on each leg?

9th August 2005, 11:37 PM	#8
AudioWizard diyAudio Member Join Date: Feb 2005 Location: Southern France	ChocoHolic, a little more info here. By the way, looking up "r-core transformers" instead of "r-type" may help you locate more vendors/resellers.

10th August 2005, 09:30 PM	#9
ChocoHolic diyAudio Member Join Date: Dec 2003 Location: Munich	...thanks! hm... definitely not matching to what I would have expected. But quite interesting!

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