testing the quality of metals used in transformers

My friend Supermagoo from Argentina is winding his own transformers
and he wants to know if there is a method to test the quality of the metals he is using.

He was reading that there are ways to test the quality of the ferrites used in inductors. Because in our country there are shops selling materials for making your own transformer but no one knows the specificacions (like gauss values), he is making trial and error experiments to find out the best response of the transformers, for example he test a semi built transformer and test it with and spectrum analyzer if he finds it lacks lows frecuencies he increases the core, and things like that.

So Basicly he wants to know how to achieve a precise procedure to make better transformer and dont waste too much time in the trial and error process. Maybe all the formulas and tools used in process too.

CJ i think you are the transformer guru here and maybe you can give my friend a good lesson, because is time for us to get quailty transformers made in our country

cheers.

There are really only three major types of metal used in audio stuff,

M6
50/50
Permalloy (80Ni)

Lam thickness is usally always 0.014 in., unless it is a cut C core like Langevin output, which uses 0.004 mil steel.

Some folks add Cobalt for low end, others think this slows down the high end.
Mag Metals has a Cobalt lam called Super Q.
It has less distortion, according to the lady at Mag Met.

Supermendur is used mainly in power transformers.
It contains Cobalt also. Takes more flux per pound.
Good for airplanes.
Flux densities are usually listed in the lamination catalogs.
FIgure out where the core is going to be running and adjust up or down.
Adding a bunch of iron does not guarantee a better transformer.
As soon as you change one thing, some other parameter will change.
Like core loss.

0.014 is easy to cut.
0.011 bends a little too easily.
Usually the 0.011 was used because the steel was not as good, so the thinner lams make up for core loss caused by low silicon content.
It is a lam thickness from the old days.

I use to cut 0.011 and it was a pain in the rear. Folded up like a house O cards when going thru the machine.