Glen,
The M200 series are very nice mixers. I've had
the M216 since 1989 (bought new) and
the M208 for about ten years. The thing about
the M224 is that the power supply is a little on the shy side, so it is a bit noisier than the M216 or M208. They used the same PS as the M216 and the eight extra channels are just a bit too much for it.
I can recommend the M216 if that's enough channels for you.
What I like about them is they are really compact, light and easy to mod, which I do a lot of. They sound pretty decent stock, but I've moded my M208 with newer op-amps and metal film resistors. It's very clean and quiet.
Each channel is on a separate card... it's a very nice design for a low-cost mixer. They're comparable to the Studiomaster and Mackie mixers of the same era (mid 80's).
The EQ is not transparent, but it has a certain character that I like. The pres are pretty decent for a small board. I like them better than some of the later Tascam stuff.
The mic inputs are electronically balanced, but no phantom power. I use external phantom power anyway so that's no big deal for me. I've really grown to like the M200 over the years and I use them as my main consoles for recording. They’ve never given me any trouble in all these years... still work like new.
~Tim
