The load drawn is based on the speakers used combined with how loud they are listening. Putting a typical rating on that would be like putting a 40mph typical rating on a BMW M5 as how fast it will likely be driven.
Indeed. *Not* about efficiency or supply current. Thank you for acknowledging that.
And to achieve 23 mA into 1.8 kOhm, you need a 41 V signal - and at that point the nc500 will be clipping rather badly.
Assuming anything about efficiency, or even introducing it into the discussion is absurd (as you acknowledged above).
Thank you for honestly describing yourself as such.
Dissipated as heat, but who cares? 50 mA doesn't result in very much heat, so the opamp running perhaps 10 degrees warmer than the surrounding air wouldn't be a major issue.
I'm not buying that 85% of the power is dissipated as heat. If the circuit is that horribly inefficient, then I would be redesigning it either way.
Last edited:
So why don't you calculate the actual maximum input current, so we can stop speculating? We have explained how to do it a number of times...
If in this question you're referring to the NC-500 datasheet you posted up a while back, then the 60mA figure is the maximum. I agree its not clear if that figure of 60mA is perhaps taken momentarily on power-up, or if its there because the design permits OEMs to engineer their own board and they shouldn't assume they can have more than 60mA.
I'd hazard that 'where did the other 50mA go?' is making some kind of wrong interpretation of the data provided, but its not perfectly clear, even to this non-layman.
You don't have to buy it. Nobody is selling. The only one talking about efficiency is you. It doesn't matter.
So where do you suppose Richard got the idea that the NC-500's draw between 50-70mA max from the buffer? After all he had them in his lab to test with his high end AP gear
Why do people by 1000w amps when at typical listening levels we never exceed 10w output? Why not just buy a 10w amp?
No idea - he isn't part of this discussion, except through a proxy (you), so without any context and without any ability to ask him clarifying questions, all we can say is "who knows?".
Appeal to authority is generally considered a rhetorical fallacy.
Bavmike, how about taking the rest of the day off from this forum, use your precious time to read this:
Biasing Op-Amps into Class A
and come back (preferably not before tomorrow) with hopefully a new, fresh look ......
Biasing Op-Amps into Class A
and come back (preferably not before tomorrow) with hopefully a new, fresh look ......
Well it seems that the fact the SIL-994's are so powerful and can drive a 150mA into a 75 ohm load, and 30 in pure class A is so wasteful. Perhaps it's wasteful buying an amp over 10w output just the same. Or is there any reasons sound wise we don't want to take amps right to the limit to get the best out of them ?
Yes the 994's come out of the box running in class A up to 30mA. It's common knowledge that biasing into class A sounds better As Abraxito said, the lm4562 would probably only handle 1mA biased into class A.
Why you are into class D when you think class A sounds better?
Besides, when you would take the effort to read that article I linked, you would know that you can force an opamp into class A, also an LM4562 to drive a NC500.
Besides, when you would take the effort to read that article I linked, you would know that you can force an opamp into class A, also an LM4562 to drive a NC500.
No not at all. The opamp in the buffer is no different. Running it in pure class A at levels far far below the maximum capabilities is no different than buying a 1000w amp and only using 10w of it. Because it sounds better!
You require some sort of buffer between a DAC chip and the class D NC-500 module. When this buffer is 100% discrete, and running in pure class A, it sounds far better. Likely the reason everyone says with the SIL-994 not a single detail is lost, but at the same time the sound is natural without a hint of listening fatigue. Listening fatigue is one of the biggest complaints from those who have heard other Ncore based amps and passed on them.
It is more like making sure your amp can drive a 0.1 ohm load, just in case.
If you have a 1000 W amp, and only use 10 W on average, you still have headroom for transients, so there is actually a benefit from the overkill. But if you build in way too much headroom in a preamp or buffer, if doesn't buy you any benefits as the power amp will clip long before you get to use your headroom.
If you say so, but you just repeating it over and over again does not make it any more true.