[kyrill]

Electronic parts from different brands do sound different,. We have learned to accept this.
I remember in my student years in the previous century that in building kits no brand of the parts were mentioned, only their values. Because they should measure the same, they should sound the same..
We have even accepted that different copper wires sound different. OFC or non OFC ...

SO why can't I find ONE article on the net about the differences of sound produced by power transformators* of different brands, keeping everything else the same? (same amp, same transformator specs)

*There are some reviews of the sound of chokes and power (SE) output trafo's, but not trafo's of power.

I mean if wires are aleady sounding different, than trafo's certainly must sound different too; and not only in the measurable domain (inductance and capcitance)

[Carlman]

Could it be that no one has obsessed about it yet?  You'd be the first!

I have never seen a comparison either.  I picked Plitron due to proximity, cost, and other recommendations.  Are there better?  I don't know.  

If you send me a pair of 300VA transformers that produce 33-0-33 when used with a center tap, I'll compare them and post the review here.

-Carl

PS, I'd get to keep them if the ones you send sound better  

[TG]

SO why can't I find ONE article on the net about the differences of sound produced by power transformers ...

As Carlman said, probably no one has bothered to look closely at this yet.  Transformer "rolling" would be a pretty full-on obsession, even for a dedicated DIYer.  Valve rolling is no effort, and cap or resistor swapping reasonably cheap & easy.  Transformer comparison is just a bit too involved and expensive.

That said, I have swapped transformers in some projects, usually when going from a prototype to a final version, and I have noticed changes in sound between types.  Toroidal transformers do create a different sound to EI types when powering the same device, with no other changes made.

I have compared toroids, C-cores and EIs with the same ratings and heard different results (EIs are my favourite, by the way), but even I'm not so far gone as to order different versions of the same transformer from different manufacturers just to hear if their wire sounds different - mind you, a transformer is a mechanical device as much as an electrical device, and different quality construction can certainly be of importance.