A search on Google about GOSS brought a shirtload of mainly
indecipherable info
re GOSS transformer materials, and magnetic materials in general.


The people at Tortech ( aust ),
http://www.tortech.com.au/toranalysis.html
say this



"The magnetic core material for most power transformers Is made of
grain-oriented, cold-rolled, 3% silicon steel that is coated and
Insulated. That material has
lower exciting current and core losses than regular steel. It also has
relatively high saturation flux density with a high degree of
squareness. Squareness is the
ratio of residual flux density (remanence) to the maximum flux density
(saturation), or Br/Bs. The oriented grain allows the steel to be
operated at a higher
saturation-flux density than non-oriented steel.
The core material is annealed at high temperature in a dry hydrogen
furnace to remove impurities and relieve the material stresses.
Annealing also develops the
desired magnetic properties, such as high squareness and low core loss.
The steel strip Is coated with a chemical finish to ensure high
resistance between
laminations. Finally the annealed cores are varnish impregnated, cured.
and painted or epoxy coated."



There is reference to " most power transformers " being made from GOSS.
But GOSS isn't universally used, its twice the price of the non oriented
steels.

There is no mention of the U figure.

It is sales pitch.

Most transformer companies like this don't make it easy for the layman
to understand what is really available, and rely on the general
impression
that after several pages of boring transformer talk, a possible customer
will
conclude that they know a lot and place an order.

Probably Tortech do use GOSS with a high U
but we are left to assume they do.

And at the end of the day we have to try some material and measure the
VI input, and if its a low value, and losses are low and that is what is
wanted,
as well as low thd in audio trannies, we accept the material.
We don't have to know all there is to be known about the core material
production,
but there is no reason to assume anything, and i base my position on
the variability of core materials i have been sent from
various companies in Oz over the last 8 years.

Patrick Turner.