audioBliss
Active Member
We are just hungry leechers over here so don't take it personally. You're doing great work for the whole audiophile community!
We are just hungry leechers over here so don't take it personally. You're doing great work for the whole audiophile community!
Are these CMRR figures achieved with real world sources where components are rearely better than 0.1% tolerance in the output?CMRR at 1 kHz is only > 60 dB. I would like above, > 90 dB.
It's time to pick a number as a line in the sand as measure 'clipping' as being that figure. Everyone else has done it. Hypex do it. Stereophile does it. Audioholics do it. Magazines from the past did it. The power cube does it. Amir should do it.
@maty CMRR is not outstanding for Purify module, but you are comparing an amplifier module with a complete amplifier (with one exception). an input buffer can improve this parameter if needed.
Real world? Maybe a very good PA from Germany or Austria. Only € 579 at home, Spain.
PAS 2002PCA, with input CMRR > 90 dB
https://www.thomann.de/intl/pas_2002pca.htm
View attachment 28917
View attachment 28918
View attachment 28919
PS: I have been researching for years to buy or build an amplifier for my second audio equipment, so I have saved a lot of information. Meanwhile I have been experimenting with the one I have until I get an excellent sound. Problem: I think I have reached the maximum possible improvement. The sound is still 2D (less than the original) but I would like it to be 3D and to perceive sound planes with certain very good recordings.
By 'real world' I don't mean what's on the spec sheet. I was reading a paper that criticised standard CMRR measurement procedure for audio devices for giving high numbers that were often unattainable when connected to actual upstream sources because the impedance mismatch in the upstream sources degraded the CMRR. Unfortunately I can no longer find the paper to reference. It may be that it's referring to a testing method that's no longer in use, that the author was wrong, or that I failed to understand it. The claim was that the first step of the standard involved adjustment so that the drive to the device under test had perfectly matched source impedances, providing ideal conditions for CMR. Real world sources are rarely perfectly matched, and this may significantly degrade the common mode rejection when these are connected to the device depending on the design of the input buffer. IIRC the classic opamp differential buffer was an example that may be significantly degraded, while a design licensed to THAT Corp. was significantly better. I'm looking to learn, so links to standards, schematics etc. would be much appreciated.Real world? Maybe a very good PA from Germany or Austria. Only € 579 at home, Spain.
PAS 2002PCA, with input CMRR > 90 dB
...IIRC the classic opamp differential buffer was an example that may be significantly degraded, while a design licensed to THAT Corp. was significantly better. I'm looking to learn, so links to standards, schematics etc. would be much appreciated.
There will probably be a dozen vendors when these modules become available. From more traditional companies like NAD, Bel Canto and Marantz etc to smaller companies like Nord, Apollon, March etc.It's a nice trend, low distortion class D. Perhaps they can find an OEM to build these assembled. It's also awkward from a commercial standpoint to use a power supply from a direct competitor.
A problem: blue color. Your wife can kick you out of the house. Years ago I wrote to the constructor asking about some values/specs but he did not answer my mail. Now I search.
Here you go:I second the idle power consumption request.