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-   -   Are toroidal transformers best? (http://www.diyaudio.com/forums/solid-state/1130-toroidal-transformers-best.html)

walker 13th November 2001 08:19 AM

I have allways thought that toroidal transformers were better than any other common core type for amplifier power supplies. Lower impedance and less stray flux.
On the Onkyo website they suggest that this is not the case.
Your thoughts kind gentlefolk?
Regards WALKER

AudioFreak 13th November 2001 08:54 AM

This is what Onkyo says.........
<QUOTE>
Quote:

Toroidal Power Transformer

For the most state-of-the-art power delivery available-the custom-built toroidal transformer employed in the TX-DS989 is formed from a single strip of silicon steel, tightly wound in the form of a clock spring and wrapped in copper wire to form a silent, highly stable power supply virtually free of mechanical hum. The use of primary and secondary wiring around the entire core prevents air gaps, reducing magnetic flux, and making this very powerful, high-end unit 40% more efficient than conventional transformers.

High-Grade Isolated EI Transformers

Designed for efficient operation, even under high temperatures, these large transformers provide plenty of power reserves for today's multichannel digital sources.
</QUOTE>

It seems to me that they are saying what everyone else is saying ...... Toroidal Transformers are the best most efficient, lowest noise transformers .........

[Edited by AudioFreak on 11-13-2001 at 04:04 AM]

cp642 13th November 2001 11:12 AM

An article that i've come across states that a properly designed and wound EI core transformer beats an off the shelf toroid anytime, but at a cost.

My personal experience with EI core transformer has been somehow dissapointing so if you should ask me I'll opt for a toroid instead......

AudioFreak 13th November 2001 01:27 PM

this maybe true, but if you are going to get a custom EI core transformer of course the stats will be better ..... if u compare a custom EI core transformer with a custom toroidal transformer then things start to even up again but with the greater efficiency of toroids and less stray flux .......

personally i use custom built toroidal transformers .....

hifiZen 16th November 2001 08:59 AM

Yeah, nothin beats a toroidal. It sounds to me like Onkyo just doesn't want people to think the EI trannies they're using are no good... ;)

cp642 16th November 2001 12:32 PM

just a thought............
 
" I keep saying "theoretically" as whether and to what
extent this will be true greatly depends on both
transformer materials and equally to its winding. If wound properly, so that a secondary ends on the spot where
it begins, if good quality rings are used and if good quality wire is used, then it will display all of its benefits to a considerable degree. In practice, unfortunately, I have seen far too many toroidal transformers which were poorly made, despite bold manufacturer claims.

Actually, you can check up on this rather easily. Using all necessary safety precautions, connect the transformer
to the mains, then connect your multi meter across the secondary and measure its quiescent current
consumption (the current it uses up with no load). Remember that by default, larger capacity transformer will use
more current than a smaller one, and in all cases, you are in the milliampere range, below 30."
------------------------------------------------------------

I was wondering how true this is......testing the quiescent current of a transformer??? For the full story check out http://www.tnt-audio.com/clinica/ssps2_e.html

GRollins 16th November 2001 03:40 PM

I've seen arguments pro and con for both EI and toroids. I wouldn't get too hung up on the point, myself. About the only reason I can see for really getting worked up is that toroids are somewhat less prone to interference. Even then, it's not that difficult to shield a transformer or, better still, arrange a remote power supply. Fringe benefits include getting any RF spray from the rectifier out of the way and more freedom to configure the circuit mechanically in a manner that suits you.

Grey

rlg_200 8th September 2006 03:25 AM

EI or laminated transformer is mostly use in power distribution, The advantage of this transformer is easy to mount and easy to wind. but if you consider the power efficiency EI is not efficient. toroid is more efficient than EI it is especially used in audio and computer electronics. beacause of high efficiency and free for magnetic interference.

poobah 8th September 2006 04:43 AM

Quote:

high-end unit 40% more efficient than conventional transformers.
That statement is a little hard to grasp...

:xeye:

anatech 8th September 2006 12:31 PM

Hi cp642,
Quote:

Actually, you can check up on this rather easily. Using all necessary safety precautions, connect the transformer
to the mains, then connect your multi meter across the secondary and measure its quiescent current
consumption (the current it uses up with no load). Remember that by default, larger capacity transformer will use
more current than a smaller one, and in all cases, you are in the milliampere range, below 30."
And it's new meter time! I read this as you hanging a meter set to mA across the secondary. Poof!

What you meant was, measure the primary current with all secondaries unconnected. This, of course, should only ever be done by a qualified technician as you are directly on the mains now.

-Chris


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