Mr. Jute said:

I dont actually know where the Velleman K4000 trannies came from, Tom. But a good guess would be Antrim Transformers, in Northern Ireland.

I always thought they were made by Amplimo, a Dutch company
specialized in toroidal transformers. The measured performance sure
looks like it.
Amplimo were the first to use vanderVeen calculations for their output
transformers, and they're very good IMHO.
Amplimos can also be found in the relatively scarce, but
underestimated Miracle amplifier with 2 x EL34 PP UL/triode.
To my ears one of the finest sounding EL34-based amps ever made, and I
don't even like the EL34 :-)

--
Sander deWaal
Vacuum Audio Consultancy