Tubetec said:
Hmmm wooly , maybe not the best metaphor for what seems to be nice bit of kit .
I wonder what the sheilding material is , looks like brushed aluminium, steel or Mu metal might be a more effective shield for emi.
Does the guy publish any specs aside from impedences
max levels ,bandwidth , gapped/ungapped , be interesting to see how it compares with other transformers of similar spec .
Probably a guy in a log cabin in the middle of nowhere ,just winding away .
We actually use a mil spec winding company here in the states, although Ron Swanson winding transformers in a log cabin would be way cooler.
The company we use utilizes very old school winding technics, and have older machines that allow them to use much thinner wire than most modern CNC winding machines, which break the thin enamel wire. Very important, especially for small signal transformers with high step up ratios, to keep DCR to a minimum, and to keep phase shift and ringing to a minimum. Our transformers are designed to go straight to the tube, no weird networks to compensate for poor design and manufacturing.
We more or less send them a vintage transformer to sacrifice to the winding gods. They unwind it, count and study the windings, and do a metallurgical study to find the core material. They also note the lamination size, shape, and grain orientation. They cut their own core laminations as well, so we're not limited to off the shelf cores like most companies, and they allow us to request weird core materials. Plus they have all kinds of sweet old school tricks for improving bandwidth, tweeking freq response, saturation levels, etc. The brilliant gentleman that winds our prototypes is 70 years old.
The enclosures we use are plain aircraft aluminum, and are just considered a simple octal housing for us. Our output transformers are open frame, but our inputs our in a nested Mu metal can.
All our current transformers are ungapped, and cannot take DC on the primaries. As far as max levels, our CT41 begins to saturate at around 18DB, carefully chosen to work in modern situations, and allow you to get into the saturation point of the transformer, i.e., when the wooliness begins to happen
... Freq response is +/- 1db from 20hz-30k, and down only a db or 2 at 60K.