$6k ish amp/preamp budget

you need to choose an amp that can drive your speakers

are they

1. cone type (what is the impedance?),

2.  magneplanars (simple 4 ohm load at all freq.s - need good current delivery; low efficiency so need more power than many others),

3. horns (most efficient),

4. or electrostatics (most difficult)

you then choose a pre-amp that can interface with the amp (usually not difficult); that has the control functionality you want and sounds good

I usually use a SS amp and a tube pre.

Thanks randy-11

I was thinking Tube pre and SS amp so good to have that validated. 

"JSEs used Richard Mondafieri (sp?) of Macintosh fame's infinite slope crossovers, which give something close to 100db/octave roll offs." - NAT

5 poly drivers.
Two 12" woofers, the midrange is 6", (says 8 OMH on the magnet) One tweeter is a 2" MB quart soft dome, the other tweeter is 1" soft dome.  

I have sent an email to Source Loudspeakers. Their chief designer, John Sollecito created the JSE Infinite Slopes back in the 80s. Hopefully he'll have some info to offer.