Toroidal transformer versus EI transformer

[faizal]

Is there any "real advantage" in opting toroidal Xfmr insted of EI type.Real advantage means audible difference.In am little bit confused.In almost all vintage equipment's i have seen EI xfmer.Please suggest me

 

[omishra]

Old time only EI was available though leaked more magnetic field in surroundings. But it's core never saturates.
Toroidal has circular core which completes magnetic circuit within and least leaked. Small size and more power packed but core saturation during inrush possible. There are more differences - read here.
But in some cases EI core transformer has advantages too, example capacitive noise coupling of main into secondary of toroidal is more than EI.

 

[trittya]

There are more differences - read here.

Thanks for the link, Mishra Sahib. :thumbsup:

But in some cases EI core transformer has advantages too, example capacitive noise coupling of main into secondary of toroidal is more than EI.

Does that have much to do with the fact that most valve amplifiers use the EI core trafos rather than toroidal?

TIA and warm regards.

 

[marX]

IIRC, the Yamaha A S500 amp uses an EI transformer but many amps in that price ranges uses Toroidal.
I wonder why Yamaha used an EI transformer with the 500.

 

[kanwar]

The best of all is R-core

The main reason behind it is in both EI and Toroidal you have primary is wound on secondary which induces all the Radio frequency noise into your secondary which will eatup your micro and nano details in the sound. At the same time your noise floor will increase.

Faraday Shield[between primary and secondary] is sometimes used to suppress the RF ingress superimposing on secondary.

When it comes to R-core The primary and secondary is isolated and your entire ground plane is isolated from primary and secondary. Which reduces your RF substantially creating inky black backgrounds and good micro dynamic sound in your HF region preferably.

we have done A/B comparison with the three transformers.

Even with Split bobbin EI Transformer you can have separate sections for primary and secondary without overlapping each other.

BTW i have seen R-core transformers which have both halves of primary and secondary windings overlapping on both sides of the core, one such example is Grundig SVX6000 Preamp. In which the both primaries of 110V each were used in series for 220V operation and same way the secondary was also wound over the both sides as halves.

 

[pradeepkumar]

Toroidal transformers have higher capacitance between windings and have excellent freq response - up to 20Khz or more. EI types have a poor high freq response, so in a way, the EI types can reject high freq PS noise better than toriods.