Carnhill vs Sowter vs Jensen vs lundahl transformers vs ?

soz's, thats really an impossible question to answer, especially without  context of use? It's really just a matter of taste? I guess someone could write a 3 pager to cover the basics(i'm not qualified), but i believe it totally depends on what you're going for.

an example of this is, my custom built ribbon mics with 1:32 toroidal tranny's from samar, sound better than the lundahl counterpart to my ears, the imaging is more vivid as compared to the Lndl's more compressed sound in the same mics, assessed with use over time. Which is better? for me i wanted a little more life out of my ribbons, for someone else, they may feel the compressed sound will work better for their application.
I'm also thinking seriously about putting Sowter 1:1 input tranny's on 8 channels of my J williams modded SC delta console, to give me some gooo and slew on this super fast rig.  

Dont forget EA(ed anderson)tranny's, he's all over Capi and Hairball stuff
I think all of these trannys are really great BTW

T

Welcome, Steve!

The laws of physics are not easily avoided, so the compromises necessary to make any transformer are subject the actual application requirements. Low resistance windings (1:1 used at 600 Ohms) must use larger cores to accommodate the larger diameter wire.  1:1 used at 10K can have much higher resistance windings and therefore have a smaller core.  Designing an audio signal transformer for a given bandwidth, level-handling and size requires balancing all the tradeoffs.

Power transformers for audio equipment face similar tradeoffs.  If you want really low magnetically-induced hum in your power supply, a custom power transformer may be required.  Off-the shelf commercial power transformers must compete with manufacturers making similar products for a very low competitive price.  For that reason, the core material used is cheap -- not the more expensive M6 grain-oriented steel. Low flux density designs have lower radiated flux, but they are larger (more core) than cheap off-the-shelf power transformers.

My current project is the rework of several Altec 525A power supplies for the Lipstik vacuum tube mics.  I have designed 2 PC boards that will occupy the space previously taken up by the huge twist-lock electrolytics.  The LV board replaces the unregulated filament supply fed by FWCT selenium rectifiers. These rectifiers gradually die over the years and the filament supply was putting out 3.2V instead of 6.3V.  The new LV circuitry uses SiC rectifiers, 10,000 hr 105C Low Z electrolytic filter cap, sophisiticated Common mode filtering to eliminate rectifier pulses capacitively coupled from the high-voltage winding of the power transformer, and an adjustable low-noise regulator to set the filament voltage correctly at the tube.  The HV board replaces the half-wave rectifier with a SiC bridge and uses 25uF/600V PP film caps to replace the 4-section aluminum electrolytic can.

The original Altec Power transformer may be useable, but its faraday shield is not connected very securely -- it's a wire jammed under the lams.  The laminations are stacked 3 x 3 instead of 1x1 interleave -- a cost cutting measure, and the flux density is average for a commercial transformer.
The transformer is riveted to the cold-rolled steel chassis, so the magnetic lines of force can flow around the circuitry, bringing the hum to where it is not wanted.  I will at least use a non-magnetic spacer and SS hardware to lower the unwanted magnetic contamination of the chassis.

I may end up replacing the Peerless power transformer with a lower flux density version of my own design using a fatter stack of higher quality (M6) laminations, since it still must fit into the available space.  If I can get a lead wire onto the Peerless transformer's faraday shield wires, I can ground it more securely.   Don't know yet which approach will work out best.

All that to say that high quality will often mean larger size than normal, and therefore more cost.