I have owned several Nikko preamps and amps in the '80s and '90s including their last flagship model, the 330 w.p.c. Alpha 2000, and consider myself quite knowledgeable about the brand. AFAIK there is no such model number as Alpha 1200.
Not familiar with that particular model but understand that the older Alpha and Beta series gear is highly thought of by many.
Nikko is a sleeper brand IMO that many in the mainstream pass by because the brand does not have the same cache as Marantz, HK or some other the recognizable names from that era. I have a Nikko NR-819 and have been very happy with it. Very good tuner section and is well built.
At the risk of incurring the wrath of other members here is a link to another site where Nikko gear is regularly discussed. You might be able to find something there on your model.
There has never been a review of the Alpha 2000. As I stated above, it was rated at 330W x 2, bridgeable to 600 watts mono @ 8 ohms. The Alpha 2000 was very similar in circuitry and internal construction to the Alpha 650. I compared the Alpha 2000 to a Hafler XL-600 (305W x 2) and Legacy High Current Amp (220W x 2) in my home system, and the Nikko bested the two amps in terms of smoothness and effortlessness. The Hafler's upper and mid treble were notably grainy compared to the Nikko.
Other components in the system at the time were California Audio Labs Icon CD player, B&K MC-101 preamp, and Mission 765i floor standing speakers. Speaker cables were Audioquest Indigo and interconnects were Audioquest Lapis.
I owned the Nikko Beta 30 and Beta 600 preamps and found the amps to be better. At Audiokarma you will find a concensus on this.
i bought nikko alpha 2000 year ago did connecting to speaker Audes 037 the owner warning me not turn volume on too high , but when i listen to music so good i forget it seem now it my bass coil blown out and twiter it gone too > now i don know with speaker can handle this amp. some friend tell me buy bose 901 and i did but some how sound come out not good or I did not install and setup right
You should not have had a problem with the Audes 037s. The issue is not as much the speakers being able to handle the amp as you being able to recognize when you are overdriving your speakers by paying attention to how they sound.
When music starts getting "hard" sounding and the woofers sound like they are starting to bottom out (voice coil hitting the bottom of the gap in the magnet), you know you are driving them too hard.and need to reduce the volume level. The Mission speakers I listed above were rated to handle around 150 watts if I remember correctly. I never had a problem with them and the Alpha 2000.
Why did you waste your money on Bose speakers ? What is your budget for new speakers and size of your listening space ? Maybe we here at AR can recommend some good speakers to you.