At all levels above low wattage the fans in commercial amps like Crown can be quite obtrusive. I don't recommend them unless you can put them outside your listening room.
BPs NCores probably the best measuring of any amp but you have to put them together yourself or look out for a second hand 'made ' pair.
Keith
At all levels above low wattage the fans in commercial amps like Crown can be quite obtrusive. I don't recommend them unless you can put them outside your listening room.
Not just chips. They all use nCore boards, some with SMPS, some with linear PS.Not any more. Bel Canto Ref 600M uses nCore chips, as does the NAD M22 amp, and does the new line from ATI, etc.
At all levels above low wattage the fans in commercial amps like Crown can be quite obtrusive. I don't recommend them unless you can put them outside your listening room.
That depends. Yamaha P2500S and Crown DriveCore XLS are silent. I can drop the hammer with the XLS and you can't hear the fan. At All.
I have not repeated that test with modern amps though I believe some of the better class D gear, like the Hypex or others might manage the trick or get close.
.
Members of LTS, the Swedish AES, have claimed on Swedish forums that they have done before/after blind tests on various well regarded class d amps, and that they still haven't found any d amps they deemed transparent enough to write about. They refuse to provide any other details though. I think that they want to do it thorouhly if they put a product down.
This surprised me, as objectivists in most other places seem to praise ncore etc. But I have no reason to doubt them. They ususally avoid audiophoolery. Would be interesting if others with the technical skills to conduct before/after tests could put the Ncore under the bench: is it transparent or not?
How did you know they weren’t transparent, how did you know that your reference was ‘transparent’.
I haven’t much if any difference between good measuring solid state amps if they are capable of driving the loudspeaker.
Keith
This method isn't an ordinary A/B test. The point is to insert an amp into the chain while keeping the original power amp - an amp before an amp kind of - to see whether the sound changes audibly. If it does change, it means that the amp isn't fully transparent. Doesn't matter if the rest of the chain is non-transparent. If an amp inserted into the chain changes the sound in any way whatsoever, it means it isn't fully transparent.
But one may debate how audible this will be with ordinary listening, of course.
What? What's not to say the 2nd amp is transparent and it's the first amp that's changing.
That makes zero logical sense.
You're thinking of the Straight-wire Bypass Test.Hmm a power amp driving a power amp, I would stick to measurements, this is Serge’s territory,
Keith
You're thinking of the Straight-wire Bypass Test.
It's a relatively easy thing to do with line-level devices, a bit more complicated for amplifiers, but yes, still doable.
It requires the dummy load to be a good simulation of a loudspeaker, including RCL parameters, but also any back emf which is rather more difficult to do. Alternatively, a sound proof room to put the dummy load in, as this 'dummy' load needs to be another real loudspeaker if it's to be a real test of an amplifier driving a loudspeaker.
As I said, doable, but a bit of a faff.
S
Like making your own jerky ... faff..Faff:
to spend your time doing a lot of things that are not important instead of the thing that you should be doing: I wish you'd stop faffing about and do something useful!
faff about/around Definition in the Cambridge English Dictionary
iridium.
Hmm. I may be a total rube here. But, from what little I know, the test amp would only be able to operate at the extreme low power end of its output so as not to overdrive the following reference amp. Yet, most all solid state amps exhibit increasing noise and distortion as a % of signal as output level is reduced.They have been doing this for 30 years. I think @Blumlein 88 can explain better than me how it functions, since he has done it himself. The point is simple: Somehow they are able to insert an amplifier into a chain before the last amp that is driving the loudspeakers. If there is any audible difference between the two - the chain with and without the amp under test - it means that the amp under test is adding something to the signal. Nothing illogical about this.