Mike, these are HN transformers. Does the lamination material make a difference in a 1:1 transformer? If so, what would the difference be between the HN and say cobalt or M3/M4 sound wise?
Does the lamination material make a difference? From a technical POV, yes. The higher perm materials will produce a greater
amount of L at any given drive level. Hi perm materials also tend to have less core losses.
But.... if you recall a long time ago I had put up in the specs (inductance in this case) for various grid chokes--- accdg to the
core materials employed in each one--- but rather than list a quantity I stated the L "qualitatively"--- using language akin to
"good", "better", "best". I forget the exact terms I used for the chokes but the point was that even the least amount of L of
any of the grid chokes was more than sufficient from a technical POV for the absolute greatest majority of applications.
In one sense--- depending on the specific application--- what is often required and of the greatest import is having or maintaining
a minimum ( a healthy min--- not a starved min) of L---- once you get to the good quality level of acheiving sufficient L---- the cases
where L is then multiplied manifold by a higher perm material may be of limited technical and practical benefit.
Remember that--- in many cases where your using a choke (or a transformer's pri L) you will have a policeman on the job--- meaning
that there will be a R component in parallel with the L. What you want is for the R to be dominant. This is acheived by making the L
very, very large compared to the R.
From this one technical POV even our M3\M4 10K:10K input trans has more than sufficient L to do it's job well. The rest of the core
materials are mostly "icing on the cake" from this consideration.
Now--- onto the subjective--- the issues of "how do they sound"---- this is the "art" part of amp building. Each will sound (in an
appropriately high resolution circuit) different--- but ranking these different "qualities" of sound is subjective to some greater or lesser
extent. We have customers and OEM's who vary from preference for say all M4, to others who like pinstriped cores, to yet others who
prefer an all nickel core. Unfortunately--- very few listeners will ever have the chance to "audition" in the same circuit multiples of the
same trans with differing core materials to form their own opinions.
And remember that "core materials"--- as sexy as they are--- are only a part of the overall "goodness" in a transformer---
other materials (insulating mats, magnet wire used, lead wires, terminal arrangements, etc) also have an influence on "goodness"---
as doesn't build quaity (how well is the coil wound, how well is the core stacked, etc) of the trans. It's a trinity of virtues
that must be present--- virtues in all aspects of the design, materials, and workmanship.
And when you throw in the "buzz word" mentality--- that core mats are "sexy"--- you can get steered in the wrong direction by
just focusing on one of the three virtues that makes for a "good" transformer. An all nickel core in other words is NOT a guarantee
of a good quality transformer overall. I'd rather a great Peerless output trans design built on pure M6 core than an inferior design built on
an all nickel core.
I'd love to see some comments on different core mats--- especially from users who have listened to the same trans otherwise.
MSL
