Old Acoustic Research Amp Model AU

Im looking for information on an old AR Stereo Amplifier I picked up. It has a plain Brushed Gold front panel, with 5 brushed gold knobs, all the same size, the center three are dual post knobs. the only other thing on the front is a switch for Speaker/Monitor and a red lens in the upper right hand corner for when the power is on. It says AR inc. in the lower left hand corner of the front panel. On the back are the inputs on the right and the speaker outputs (slotted screws) on the left. Also on the left are three fuse holders. Ther is no Model number on the bottom it just says "Model AU". It does have a serial number of A002806 on a small piece if tin riveted to the back. It is enclosed in a black mesh case. is roughly 12 1/2 inches wide, 8 inches deep and 3 3/4 inches high. It weighs about 20 lbs. It is in excellent condition and sounds beautiful. There are no tubes inside but i can see 4 round output transistors and a large aluminum heatsink looking in from the top. Any info you can get me on this item would be appreciated. I believe it to be made around the 1970-71 year.
Hi Popper, I bought one of those AR amps new, way back when. It sounded okay, as I recall, though my system at that time wasn't as high resolution as it is today. It did, however, blow up on me for no apparent reason. AR rebuilt it at no charge and I sold it to a friend because I liked my Dynaco 120 a bit better. A couple of months later the amp blew up on my friend and AR had to repair it once more. So my sample appeared to be unstable, but I don't know if it was representative of typical production. This is one of the only amps I've owned that failed in service.
Plato Any Idea as far as production year and/or if it would be a sought after relic now?
I believe the AR amp first appeared in the late 60's ('68 or '69 maybe). It is quite possible that some people collect them. The amp actually got very good press in Stereo Review, High Fidelity, and Audio magazine if I recall correctly. That's why I bought mine -- also, I was using AR speakers at the time. At the time of its introduction it was considered a very high-powered, low-distortion model. Obviously this was before the 200 Wpc models appeared. I'm pretty sure the AR was rated at 60 Wpc @ 8 ohms and in tests it put out over 90 Wpc into 4 ohms before it clipped. It is a rather cool-looking unit. Happy Holidays to you!
Popper, I forgot to mention that AR offered a matching tuner, which I also owned, and I believe they marketed a receiver, which was basically the same integrated amp and tuner combined on a single chassis.
Thanks Plato......having a hard time finding anything out about this....youre the first.