I'm in Beijing--which transformers should I buy for full-range ESL's?

[rkellyfitz]

I'm an Amercian living in Beijing, and have access to a goldmine of cheap components at the electronics markets here. I'm trying to get parts to build a full-range ESL with wire stators--I would like to extend the low range as much a possible.

I see in Calvin's posts that he recommend toroids, and I can get many toroids very cheaply here in Beijing. What would be the ideal specs for toroids to drive full-range ESL's with my 50W 8 ohm Harman Kardon receiver?

What is the ideal step-up ratio I need? I'm guessing my receiver's 50W signal puts out about 20v, so I would need at least a 1:150 ratio through the trannies to get the 3000v needed to drive the stators with enough power to get good low end performance?

Should I try for a ratio higher than 1:50?

How can I make sure the ESL's stay closer to 8 ohms (rather than 4 which most ESL's seem to be) so I don't fry my receiver?

Thanks for your help!