Check with Mike Kelly at Aerial - Those speakers date from his reign there @ ADS. www.aerialacoustic.com Good luck. L1590s - probably the best floor stander they made, at least in my experience. (had L1290s for a long while)
the PA1 Biamp modules are a nice addition. They come up from time to time on Ebay or here on Agon... I think they fit L1290s and L1590s, but not sure. In some ways the L1290 and L1590 are basically poor-man's-Aerials. The philosophy is similar (no surprise there). By the time they got to the M-series stuff, Mike was out of the picture I think. (had left to start Aerial)
For anybody alive, ADS gave specific instructions to me about 26 years ago for the L1590 and C-2000. Remove c38 and c39 (size about 6/16 x 7/16 x 2/16 inch, color redish brown, marked ".1k 50/100"). The cross over selector is set to prog. and the crossover program switches in the back are set so each switch (the little circular hole in each switch) is at the bottom position. Before the removal described, this configuration provides the 300 Hz crossover and 0.68 filter Q. There are 15 other combinations of switch settings possible. If this is relevant to you, I would appreciate your response
Yes, the thread is old. So what. good informations lasts an ETERNITY.
Here is what Michael Kelly says about the ads c-2000 crossover mod TODAY, just this morning (to my displeasure) >:
I am sorry, but I don't have any documentation on these old ADS products. I certainly don't remember any of the details you are asking about. I am afraid I can't help you.