Aha.... a great period of experimentation. Briggs' fun books of Wharfdale experiments. I played with that unique B139 for a while (you may recognize the "theoretical piston" value for motional feedback applications).
So given your talents, doubly odd that you are not considering DSP and "electronic clutter" instead of the opposite????? Why fuss with the ragged mechanical edge when you can just use a well-engineered sharp electric cut-off for the mids?
Amps are cheap, esp if you buy them at the Salvation Army store, as I do*.
Ben
*Full disclosure: only my ESL tweeters are currently being driven by a 1975 JVC receiver I found at the Salvation Army store (lovely potted 6V6 tube output transformers by Thordarson are used for the matching with roughly 1300v bias).
So given your talents, doubly odd that you are not considering DSP and "electronic clutter" instead of the opposite????? Why fuss with the ragged mechanical edge when you can just use a well-engineered sharp electric cut-off for the mids?
Amps are cheap, esp if you buy them at the Salvation Army store, as I do*.
Ben
*Full disclosure: only my ESL tweeters are currently being driven by a 1975 JVC receiver I found at the Salvation Army store (lovely potted 6V6 tube output transformers by Thordarson are used for the matching with roughly 1300v bias).
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