I assume what you are really saying is "I prefer the sound of the NC500 with the 994 buffers over the Hypex NC400", unless you have developed some objective criteria.
It clearly is far more capable of driving the 60mA load the NC-500's present. So for the deaf who can't hear the difference for themselves, an opamp that has a manufacturer specified limit of 23mA into a 600 ohm load, it's not going to drive a 60mA load as good as an opamp that can drive 150mA into a 75 ohm load without breaking a sweat. Not to mention the SIL-994 operates in pure class A up to 30mA. 7 mA higher than the max recommended load for the LM4562.
How about factual arguments instead of going down the usual avenue of silly slurs?
Here's the holy grail of ESS 9018 based DAC's. What every OEM manufacturer interested in building the very best ESS 9018 based DAC should do, is simply buy these evaluation boards and pop them in a case. Sell for whatever you want because it's the best it can get. If anybody thinks otherwise they are wrong.
You still insist on the erroneous 60 mA number? Can you please provide a link to a specification justifying that number (or a calculation/model we can verify - as many others have pointed out, it is not rocket science)?
I have shown a screen shot of the datasheet that shows it. That's good enough. If you don't trust Hypex, switch to Anaview.
Ah, sorry, it must have been one of the many tapatalk links. Can you repost it?
jeeeeess 60mA again??? it's current draw (DC supply from regs) not current output required for NC500, is it so difficult to understand or my English is that poor?
I assume you are talking about this:
As has been pointed out several times, it specifies current draw *by buffer from regulator*, not nc500 from buffer.
We seem to be going around in circles here.
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It's an example of another evaluation board. Most manufactures make evaluation boards for OEM's to quickly evaluate their products. But the intention is not an example of the best that can be done. For example I had the Exasound DAC board out of its case on my desk when Dustin Forman the engineer behind the ESS Sabre chips and the designer of the evaluation board came over day. He seen it on my desk and said "what's this?" I said it's the Exasound E20 board. He picked it up and studied it for a bit and shook his head. He said " that's an exact copy of my reference board output stage what a joke" "I can't believe they copied the reference board to an exact T, it was never designed for high end applications"
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I assume you are talking about this:
As has been pointed out several times, it specifies current draw *by buffer from regulator*, not nc1200 from buffer.
We seem to be going around in circles here.
Nc1200? What's that have to do with this? It clearly shows the buffer circuit draws a max of 60mA from the + reg and 50mA from the -reg. And that's the buffer by itself. Not the modulator section which is also driven from the same regulator.
Yes and once again, tell me the efficiency of the buffer circuit and we will have the current draw from the amps. From what I hear modern IC opamps are in the high 90's for efficiency %. That would bring it down by a few mA.
Of course meant nc500. Yes, buffer draws that from the regulator. But we are not talking about current draw, but output current from buffer/opamp.
That it what is drawn from the regulators when driving the amps to the full 14.6dB gain that the buffer is capable of. To find out how much of that current is being drawn from the amp, we must know the efficiency of the buffer circuit, and subtract the losses out. It should be over 95% efficient.
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You tell us.
Modern opamps can reach efficiencies that are that high when operating under optimal conditions. I don't think efficiency was the prime criteria in the case of the circuit we are discussing.
By the way, anecdotes and bad analogies are not facts.
Even if it's only 50% efficient, that still takes the LM4562 well over the recommended limit. Being that inefficient the thing would probably be hot enough to melt to solder that holds it on as well.
nobody cares about efficiency of the opamp, and 60mA (maximum) current draw is total required by the buffer board with all of its loses not just opamp itself, do you know efficiency of the 994 in this circuit or by itself? does it matter? if it can deliver enough current for NC500 than it sufficient no matter what's efficiency of buffer circuit
When I am right the UCD 180/400 series power amp sections present comparable load, some 2k, to the input buffer. These use LM4562 to good effect. What am I missing here?
Bavmike you continue to consume twice as much room on this forum as necessary by continuously completely quoting of former posts when replying. Sigh.......
Bavmike you continue to consume twice as much room on this forum as necessary by continuously completely quoting of former posts when replying. Sigh.......