Summary: The only downsides here is that Harman/Kardon has discontinued this outstanding product, and that the owner's manual is next to useless. The manual wasn't a huge pitfall for me because if one can set up an AV receiver (and I can) then one pretty much knows what to do. Otherwise, this amp will blow your drawers clean off. Period! I am using it configured at 4 ohms resistance where the advertised output is 300 watts RMS per channel.
Summary: Nice amp but the instruction manual is by far the worse I have ever seen in my life.Harmon Kardon has a good reputation but on this alone it was a big Flub.They may as well have left it out of the box.
Epic Sound!!!!!! HK990 Amplifier is simply perfect sound!!!!
Eric Worman, Amazon
24 May 2014
Summary: The look and the sound lives up to the hype, it's exactly as Harman/Kardon describe it. This powerhouse HK990 Amplifier has all the options you could want. My love of old vinyl records has been taken to a new level... I didn't think it possible! This bad-boy sounds epic no matter how loud I turn it up, and it definitely gets even better after the break-in.
Summary: Bought this amp for about a year now. This amp is used to play CD (and SACD) by a Sony SACD player (scd-xa5400es), driving a pair of Gallo Ref 3.5. Typical of a dual-mono amp, which has two transformers (one for channel), the sound is very smooth. The power is more than adequate, and the details are also great.
Summary: This unit is really SOLID at reproducing sound. Beware if your speakers only cover up to 20k Hz., however. This HK unit puts out well above 20k (that's the first harmonic of only 10k) so speakers that can only handle up to 20k have a tendency to clip resulting in distortion at higher frequencies. That's exactly the reason why owners of this unit think it too harsh at higher frequencies. Many speaker manufacturers make newer models that can handle this.
Summary: I have a 2.1 stereo system so when I read the reviews for this amp I thought it would add several features missing from my system. I was looking forward to the built-in dac and room correction most but the added power also interested me. I ordered directly from Amazon and the amp arrived in perfect condition. The amp is big and heavy and imho a beautiful piece of work when off.
Summary: If you're not picky about your audio - don't read any further. If you are seriously considering this amp you probably are a pretty serious hifi enthusiast anyway. I just received the amp yesterday and have spent several hours of listening with it. The way you hear every piece of new gear is relative to what you already have. So first let me explain my set-up so you get a sense of where I'm coming from...
Summary: I dont write many reviews, but im compelled to do this one since im so impressed with the HK990. I recently got into Hifi about 6 months ago. Like anything i do, i get a little obsessed. I went and bought an NAD 375bee amp for about 1300 dollars. It was ok but I It wasn't really satisfied. Sound was colored with warmth and crisp extended highs were missing.
Summary: I purchased this item in October 2011 and connected it to my Pioneer multi-CD player and Phillips 4 ohm speakers via a digital cable. The sound is excellent. Also, I had to contact the manufacturer for help setting it up and found that HK customer service was superior.