New Bel Canto REF600M using NCORE


Wow!!..Looks like John hit another home run at Bel Canto with the just released REF 600M using NCORE amplifiers. 300 watts into 8ohms. $4500.00 a pair. The REF 1000M is out of production. I have a feeling this is Bel Canto's best amp ever below the Bel Canto Black. Look forward to Guido checking it out.
audiozen
rampage60
I would stick with the XA160.5's as the ML's like all of them go down to 1ohm in the HF and this is where Class D has real problems.

Cheers George

Steven Stone reviews the Ref 600m in the January issue of the Absolute Sound. In his conclusion, he states, “To my ears, it is good enough to qualify as the best all-around power amplifier I’ve heard to date, regardless of technology or circuit topology.” Chalk up another win for Bel Canto!


While Mr. Stone does not dwell on it, he does note, “ With the Ref600M powered up I could hear only the faintest hiss if I put my ears within a few inches of the Spatial’s coaxial driver [his review speaker]”. He later compares his recently refurbished Pass Labs X150.3. “After its return from the factory, the Pass was almost as quiet in terms of noise (without a signal) as the Ref600M, with only a slightly higher hiss level and zero hum.”


I find this very interesting. How common is this hiss/hum issue? Is it caused by class D topology? Seems not, given the reviewer experiences this even with his class A/B Pass amp. And is this issue caused by every product of a certain design or does it depend on what other components are in your system? All three of the class A/B amps I’ve previously owned were completely silent when powered on but playing no music. Putting my ear to the speakers revealed zero sound. Then I got my current Audio Research DSi200 integrated amp (class D) and it does produce a faint hiss from the tweeters and low level hum from the woofers of my Revel F208s. Close up, it is easily heard, but it’s faint enough that it can’t be heard from any further than a couple feet away, even in a silent room.


I don’t feel this hiss/hum thing is a deal breaker. My current system plays music very well. But ideally, I would never experience hiss at all.



No hiss or hum with my Bel Canto ref1000m or C5i. In fact noise floor is lowest I have heard.  
I’m using ICEPower units and have no such issue. The noise from the Parasound P7 is far worse, and still only detectable close to the speakers. If Bel Canto is using their own linear supplies however I could see this as an issue. Also, digital amps like ICEPower and nCore tend to have truly differential inputs that aren't very happy with single ended inputs and prefer transformer coupling in those cases. I wonder if this is what was experienced?

<< shrug >>

Erik
All this talk about noise/hum is a bit mute, without proper bench test results.

The way to "pseudo" see what is noisier than what without looking at them on the test bench, is to disconnect the preamps and put shorting input plugs on the power amp inputs, this is a better layman’s way of saying what noisier than what.

BTW some not all Class-D’s modules, don’t even switch their main section on, if there’s no signal present, they may appear to be on. And then there’s different amp gains to consider as well, as this also has a bearing on noise levels.

Cheers George