Well, I wish I could retract my posting!! (If moderator can do it, please go ahead). It turns out the noise was only happening when the amp was placed within the media rack. I live in a furnished house with a decent sturdy media furniture (I wouldn't have bought such a thing but it was still decent from audiophile standard). After I removed the silly back plate (you know, with a tiny cable hole), the amp compartment becomes a cubic-shape tunnel, with four sides blocked and front and rear surface open. This particular configuration must have generated some kind of resonance. After I took the amp out on the floor, it became dead quiet. Oh well...
If I may add a few more cents, CS600 is a fabulous amp! I am driving Harbeth M30.1 (which is also awesome!). I was a bit worried about the low rated power considering the low sensitivity of M30.1, but it was not a problem at all to fill my 5m x 7m living room (with the space behind the listener wide open). Moreover, the lush/silky midrange was quite expected, but I was most impressed about how it reproduced acoustic bass with such weight and authority! Now I understand why so many people were talking about Leben.
BTW, I had a chance to side-by-side audition CS600 with CS300X. While CS300X had the same and perhaps a bit better midrange, which was understandable at the time as my CS600 was right out of the box, CS600 clearly stood out with bigger soundstage and scale. Overall, I am so glad that I spent the extra money for more power, especially for my Harbeth.
Many Harbeth owners who are hesitant to try this low powered amp, rest assured that you will have more than enough juice, unless you want to crank up the Zarathustra.
If I may add a few more cents, CS600 is a fabulous amp! I am driving Harbeth M30.1 (which is also awesome!). I was a bit worried about the low rated power considering the low sensitivity of M30.1, but it was not a problem at all to fill my 5m x 7m living room (with the space behind the listener wide open). Moreover, the lush/silky midrange was quite expected, but I was most impressed about how it reproduced acoustic bass with such weight and authority! Now I understand why so many people were talking about Leben.
BTW, I had a chance to side-by-side audition CS600 with CS300X. While CS300X had the same and perhaps a bit better midrange, which was understandable at the time as my CS600 was right out of the box, CS600 clearly stood out with bigger soundstage and scale. Overall, I am so glad that I spent the extra money for more power, especially for my Harbeth.
Many Harbeth owners who are hesitant to try this low powered amp, rest assured that you will have more than enough juice, unless you want to crank up the Zarathustra.