Alan,
If you're interested in a vintage mixer look at the older Biamp 80's vintage equipment. I personally prefere the Biamp over the Sunn mixers of the day.
After Conrad, the founder of Sunn, sold Sunn to the Hartzel Corp, he and another gentleman started Biamp Systems - making mixers, power amps, electronic crossover, graphic equalizers, compressors, etc. - that were really excellent. My suggestion would be to find a good condition Biamp 83 series mixer console - 883 ( 8 channel), 1283 ( 12 channel), 1683 ( 16 channel ).
The 83 series has for each channel a pad/trim control, one effects send ( post fade and EQ),one monitor send ( pre fade and EQ ), 3 EQ ( Low, Mid, & High ) pan for the subs, and a slide fader. It can be used mono, or as I use it, in stereo using the sub 1 and 2 as L&R outs. If you get the 21 series, there are more options in the master section, and an added aux out ( post fade and EQ ), and 4 band of EQ per channel, but its a lot heavier. The Biamp 42 series is even bigger and weighs a ton. I think it was meant more for studio use.
I've used Biamp mixers and power amps exclusively since 1981 and have had no problems with them what so ever. I used them professionally 5-6 nights per week on the road and never had a problem with any of the equipment. I presently own two Biamp mixers of early 80's vintage - a 1683, and an 883R 8 channel rackmount, and both work great and are clean and quiet to this day. The only negative thing that I have to say about the Biamp mixers is that the built in reverb is rather tinny and cheap sounding. It's almost as if putting a reverb in the mixers was an afterthought. I always used outboard effects such as a couple of Roland RE-301 chorus Echos, so I never used the onboard reverb. Other than the reverb, I think that mixers sound great.
I also have two Biamp stereo power amps - a TC-120 ( 120 watts into 8 ohms and 200 watts into 4 ohms ), a TC-60 ( which is 1/2 the power of the 120 at both loads) and a Biamp SM-23 stereo two way electronic crossover. All are original and work fine. The power amps sound good and are very dependable, but are rather old school and weigh more than amps today. You can buy lighter amps today that put out more power. That's just my input on the subject. If you have any more questions, email me at Kurzpiano88@aol.com
Rob