Audioshark was probably the most anti-class D forum on the net up until the positive feedback from anti-class D guys kept pouring in constantly and consistently regarding the Nord's. Now anyone who trashes class d on the forum now looks like an idiot. For me that's a change for the better. I'm a firm believer Ncore amps can be the perfect amp for EVERYONE. It's rides 100% on the input buffer implementation.
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760uV is the ripple noise of the SMPS feeding the regulators with 1uV ripple and 110 PSRR from 20Hz-20Khz. If you know about other SMPS's with ripple noise better than 760uV, and leakage current better than 25uA, please share. When you combine this SMPS with those regulators with 110 dB PSRR from 20-20k, the ripple drops down to 0.00228uV from 20-20K. So the noise bottleneck becomes the 1uV of the regulator.
Here's the regulators we use in all of our products. However in the Purestream DAC we use these same reg's as voltage step down reg's to feed the 8x LT 3042's on the DAC board.
https://www.belleson.com/store/SPZ-High-Current
http://cds.linear.com/docs/en/datasheet/3042fa.pdf
https://www.belleson.com/store/SPZ-High-Current
http://cds.linear.com/docs/en/datasheet/3042fa.pdf
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Ah, yes, that is truly revolutionary. How could I have missed that?
Bruno must be so happy. He spent years doing research and development, and came up with an almost brilliant class D implementation, but just couldn't get perfect, no matter how he tried - until you guys revolutionized everything by finally figuring out what was wrong and solving the issue. No hard maths needed, no complicated R&D - just buying the right part and suddenly angels sing and sunlight fills our world. Thank you for making the world a better place for all of us!
After all of the years posting on this thread you still don't understand the intentions of Hypex with their products? The reason there's no input buffer on the NC-500's is for the exact reason specified right on the datasheet. Bruno knew full well that his neutral input stage on the NC-400 and Mola Mola Kaluga amps wouldn't be for everyone. But they are an OEM company, so the plan was to leave it to 3rd party manufacturers to combine their artistic touches to create products that appeal to other audiences
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OK, so you agree that the nc400/Kaluga buffer is pretty much neutral (as Bruno states), and the custom buffer is there to add "house sound" (colouring)?
I guess the stiff initial resistance to class D on those other forums (that you so successfully conquered) was really because people didn't actually like a neutral sound, and wanted some "high end" sound instead...
All of the opamps such as the SIL-994's , Sparko, Weiss, Sito etc are all very good engineer's finest efforts at perfect neutrality. They all measure impeccably. Yet they still all sound different. This is just the reality of what happens when you're not using the exact same components and layout to create a circuit. And each implementation will appeal to different tastes.
Everything is colored to some degree. Do you really think Daniel Weiss purpose colored his opamp with -152db THD+N? Or perhaps it's the 1 nV of noise that does it?
A very good piece from 1977, still relevant:
Peter Baxandall: Audible audio distortion is not a mystery
Peter Baxandall: Audible audio distortion is not a mystery
What a load of complete bollocks.
1. Theta had sold 100s of NC1200 modules in their amps well before the NC500 was even announced
2. You didn't produce an input buffer design at all. Colin uses the recommended design. The only "innovation" is a socket. Whoopee.
This is a DIY forum. Please post schematics of your work and provide guidance to those who wish to build it. Otherwise limit your posting to the Vendor's Bazaar.
Just tested it again, works for me.
Raw URL is http://www.keith-snook.info/wireles...ble amplifier distortion is not a mystery.pdf
Ahh... you have to
1) clean the browser cache...
2) go to the site, find the document there
3) click on the link THERE
Once you have used external link the "permanently moved" response is cached by the browser and clicking on the site doesn't work either... weird practice!
Ahh here we go. The position of the solder jumper for the onboard buffer clearly indicates Theta's using the onboard LM4562 buffer. How is this different from any other NC1200 amp besides the Mola Mola Kaluga? Yes I know they use a linear power supply that Bruno pointed out has EMI issues at 60hz, compared to the Hypex SMPS. Other than that the only thing I see different from the Merrill and Acoustic Imagery NC-1200 based amps is the case and internal wiring. Surely that can't have too much impact on the sound.
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