MR-80's are known for their preset buttons being intermittent. I had mine repaired at Audio Classics almost 5 years ago and still is performing better than I can ever remember, certainly better than my 78. I have a C-34 which has a few upgrades over the 33. Both are tremendous pieces. Though I find the preamps today to be just a bit more defined in the HF's. I will say they are good enough to easily critque the differences between my 5 Mac, Marantz, Pioneer, combo and CD, DVD players. The Mac wins hands down. The 2255 is a classic. I had over 75 of them in discos and over 50 of the simpler 2250 without meters in commercial installations. They have a sweet well defined high end and with critically damped speakers can really move some air. They drove double 15 inch loaded horn woofers all day without complaint, midrange horns, and HF frequency tweeters in tri-amped systems superbly. I like them particularly with Altec systems . But they worked well keeping JBL ring radiators in check. Their smaller cousins the 2150's worked very well with Klipsch speakers and their big brothers the MC2500 drove 18" Altec EV, JBL and Cerwin Vega woofers fabulously. Mac Xr7 and XRT 20 and 22 sounded great. They were so much smoother than 2300's which could be edgy when nearing the edge of the envelope. The 2255 always was graceful and very enjoyable at all levels when driving very efficent speakers or in efficent panel speakers.