Someone gave me these speakers and I will assume didn't know what they were. I didn't either until about 9 months later I pulled them out of the back room and started checking them out. They have N-1600A crossovers (well actually one does the other has some electronic crossover-looking mess strapped to a piece of wood?!?) that have a pic of the speakers right on it. I have not opened the cabinets (which the guy who gave them to me said that some guy's grandfather built them years ago and only listened to classical music at low volume. They honestly don't look like they were not factory built but when I looked underneath them there were words scribbled in majic marker regarding the wiring diagrams and such. The grilles are lattice work also! This old man must have been a professional carpenter or something to fabricate these grilles/speakers. They have a huge slot port below the speaker so I decided it would be easier to try to I.D. them from there. I took a small Streamlight LED flashlight and stuck it up inside the slot port then put my phone on camcorder mode and hit record while I slowly panned it back and forth and moved the flashlight around. This was much easier than removing the 30-40 screws holding the rear panel of the cabinet on! Low and behold metallic green-colored Altec 604C's in absolutely mint condition! Now my real dilemma here is number one... where do I get another N-1600A crossover from for a decently low price and two... what amp should I use to push these babies? I've heard that they were designed with tubes amp in mind and I was told NOT to use solid state amps EVER on them or I could easily damage them because they are not "push-pull" type amplifiers like certain tube amps which were designed for these speakers. I just came across a console called The Fisher Philharmonic and it is in mint shape also... plus it has a tube amp and tuner section! It's only 30-40 watts but that thing sound great with the speakers that are in it and they have no enclosure behind the 10" woofer... 4x6 midrange... or 2" tweeter. (These are all rough estimates of the size of it's speakers.) It has an external hookup to allow a separate set of speakers to be used but I don't know if I should hook them up or not because will the factory speakers still be playing also?? Plus the 604C's are 16 Ohm speakers right? This amp only has hookups for 8 Ohm speakers I think so how will that affect the output in wattage? Will it cut it in half? I believe these 604C speakers are rated around 75 watts (not sure if it's RMS or peak but I don't think it's peak... not for a 15" woofer) so I want to know what amp Altec designed them to be used with from the factory... I mean did Altec make an Altec amp to power these with and how did it sound? What other larger high-quality tube amps should I consider using and why? McIntosh(tube) I've been told are good but I've never heard one on them or anything else to really know what it sounds like. These things are supposed to be super-duper efficient... something like 108-110 db I think so I don't think I will need 75 watts but I just might want to have that power on tap when necessary. Well this is my first post and man was it a long one... sorry guys. I'm just soooo excited to come across these speakers that I don't know what to do. I feel like a little kid at Christmas that just opened a present that I had always dreamed of but never really knew what it looked like. Help me out guys... I know you older speaker-savvy ones out there just might even have an extra N-1600A crossover just lying around in your garage or something. Also what speaker wire(s) should I use on them? A few months ago I ran across an ex-employee of Monster Power and she sold me a 12 or 15ft. set of M2.2s and another 12 or 15ft. set of Z Series cables plus an extra Z Series cable for the center channel speaker. Would these cables make that much of a difference? I would hope so. Please send me some knowledge and help me get these 604C's sounding the best they can. P.S. A buddy of mine just came across a set of Karlsson cabinets and said they would work perfect and are extremely efficient at only 1 watt. Any ideas? Thanks for your patience with such a long post... like I said... I'm totally freakin' out over here! LOL!! WOOHOO!!!