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Transformer for NCC220

Noting the desire to support both 240 and 250 V, I offer the assembled audiophile's possibly the most versatile transformer configuration I've seen, from the Rotel 850 Power Amplifier. This has full dual-mono construction. Each transformer has 2 separate 120V primaries, with a 10V centre tap. This allows each primary to be 110V or 120V (and usefully run in parallel), and (when joined in series), 220V, 230V, or 240V.

No 250V, sorry!

850_tran by plybench, on Flickr

BugBear
 
seems strange older stuff went to lengths to ensure correct primary voltage yet newer stuff is the opposite?

I got pissed off with a certain other manufacturer stating the hum was a characteristic of their product an nothing wrong with it.
 
Mr W called round the other day and heaved a humongous EI core transformer (9Kg) into the house, along with a smaller one for the front end.
I think he intended them for my NCC300, but they won't fit in my compact build, so the big beast found its way into my Leach amp. It replaced a 1KVA toroid (8.5Kg), which had beaten a few other transformers on a subjective basis.

The improvement in sound is quite shocking. It's akin to a video suddenly snapping into focus and also increasing the frame rate.

Thank you Les (if you're reading this). Bloody hell!!! :):)
 
Mr W called round the other day and heaved a humongous EI core transformer (9Kg) into the house, along with a smaller one for the front end.
I think he intended them for my NCC300, but they won't fit in my compact build, so the big beast found its way into my Leach amp. It replaced a 1KVA toroid (8.5Kg), which had beaten a few other transformers on a subjective basis.

The improvement in sound is quite shocking. It's akin to a video suddenly snapping into focus and also increasing the frame rate.

Thank you Les (if you're reading this). Bloody hell!!! :):)

Good old Mr W :)

My six power amps all use EI transformers. I too am convinced that for me they produce better sounds then toroids.

We are of course both deluded :rolleyes:
 
Well then I am also similarly deluded. I have had 2 X 1200VA Canterbury Windings Toroids comprehensively outperformed in the sonics department by a single 500VA Selectronic RCore. I've done the switch many times on different amps the result is consistent. Sadly the EI's are hard to source unless you are happy with standard RS frame transformers which aren't bad but of low VA rating. Toroids do provide much better coupling between mains interference and the secondary winding, but that's not wanted for audio. The separation of primary and secondary in some EI and R Core Transformers using different bobbins or bobbin sections is quite fundamental to this coupling. Toroids are only so ubiquitous because of their efficiency and low hum field.

John
 
I don't think it's as simple as EI is better than toroid though.
e.g. I have a Rotel RB850 (as pictured earlier in this thread) and have used two or three amps in the chassis using the Rotel transformers. They all sound much the same and somewhat inferior to with other transfomers, including toroids. Seems to me that the Rotel transformers impart their sonic imprint on whatever circuit they are used with to some extent.

(Before Bolloxmeister comes along...) this defies logic!

It does make me wonder if some valve amps and some Japanese amps sound good because of the type and size of transformers used.
Les' transformer is not dissimilar looking to those seen in big Luxman amps.
 
I was only looking to reduce the hum, buzzing, or general unwanted noise.

not looking to open a can of worms lol

after speaking with Tiger I am happy that a custom made unit should do the job and the price was pretty good.

will know when I get them I guess apologies if I have opened an unwanted debate


i am doing a similar build to you, essentially 2 M130 amps using 2x ncc200 plus 2xCap6 boards, and im using 2xtoroids from tiger toroids (yet to be delivered in a week).
i have cases but think they not be tall enough for the troroids, so may give Les a call to see if he has any old boxes i can buy
 
I was pleasantly surprised just how good the modushop cases were and not that expensive and handy discount code on here.if you spec the aluminium base and lid is a very good case and options on size
 
Mr W called round the other day and heaved a humongous EI core transformer (9Kg) into the house, along with a smaller one for the front end.
I think he intended them for my NCC300, but they won't fit in my compact build, so the big beast found its way into my Leach amp. It replaced a 1KVA toroid (8.5Kg), which had beaten a few other transformers on a subjective basis.

The improvement in sound is quite shocking. It's akin to a video suddenly snapping into focus and also increasing the frame rate.

Thank you Les (if you're reading this). Bloody hell!!! :):)

I too have been lucky enough to obtain one of these monster EI transformers from Les. I built an amp using it and to confirm S-Man's comments, what a shock and 'bloody hell' why are we messing about with donuts. This 500va EI transformer completely outperforms anything I've used (mostly toroidal) before over 25 years by a big big margin.

51404474344_216dcc0a3b_k_d.jpg
 
I too have been lucky enough to obtain one of these monster EI transformers from Les. I built an amp using it and to confirm S-Man's comments, what a shock and 'bloody hell' why are we messing about with donuts. This 500va EI transformer completely outperforms anything I've used (mostly toroidal) before over 25 years by a big big margin.

51404474344_216dcc0a3b_k_d.jpg
Which amps are they Graham ?

Alan
 
Feckineck, that's a monster!
Completely dwarves everything else in the case!
Where does one get something like this from? Seem as rare as hens teeth wrapped up in Scotch mist...
This:
Transformers - Open Frame Chassis (esr.co.uk)
is about as close as I've come so far. Bottom of the page is a 230V to 24+24V 250VA. Price looks decent enough.

Just to clarify, this transformer is a EI type 500va with 0-115 0-115 primaries and two secondaries of 35-0-35vac and would be have to made (to order) by a specialist manufacturer.
 
Why don't more DIYers use EI's ..Size and cost. Small ones for pre amps and such not really an issue but these 350-500va jobbies do take up a lot of space. They do run warm just plugged in standing still.

Have done a bit of home work ....about £300 inc vat. Steep against a toroidal.
 


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