Hi Bernhard,
I have used Lundahl transformers before from their Pro range, mic and some line drivers, and have no doubts about recommending them. Very fine product at an excellent price, better than all the alternatives I've looked at such as Hammond, Bartolucci ($$$), Plitron ($$$), Handwound and the Japanese (big $$$) iron. They are even cheaper then the local winders can do. My mistake re the choke, the S&B being half the money but not equivalent, was merely a suggestion for Tonu perhaps to save some money. I find most diy-ers want the best, but try to do it as cheaply as possible.
What got me back into tubes after a long hiatus, was Lynn Olson's Amity: such an elegant cicuit, but it's high performance is very dependent on the transformers. I have all the tubes and parts for them, but not the Lundahls, as I can't see the point in having 20W with 105dB+ speakers. I'm now building something smaller based on triode 6BQ5s, but unfiortunately I will have to slum it

D

) and use Magnequests as Lundahl do nothing suitable. Pity, they were my preference. The other amp I looked at was Allen Wright's PP1, as I am part way throught an RTP, using LL1663's. Again, no need for 12W, and I like 6BQ5s better than 6CA7s. Allen is a great designer who's recognition nowhere near matches his ability.
Cheers