Yes let's move on to the next person who has hands on experience with the Nord's and the Rev C buffer. Since they are the only contributors to this thread that matter.
I disagree. It is only left-handed PhD's with ginger hair that *really* matter.
Colin's target market with these amps are people who listen to music with their ears. These people are thrilled with the amp. This means it's an outstanding success and he has nothing more to prove to anyone. We have seen stunning measurement data from both me and Jesus from ATM of Richard's circuit with SIL-994 and Sparko in the socket. That's good enough to prove that it's functioning properly. If for religious reasons you believe IC opamps are better, buy the version with the evaluation board, or pop an IC in the rev C buffer.
End of story, nothing more matters until the rev D board comes out.
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Indeed. Good for him! But considering that success I just wonder why some people spend so much time and energy to aggressively push the amp using wonky, unsupported pseudo-technical arguments.
Promise?
Use proven technical methods to prove that the owners of these amps aren't satisfied with their purchase then. Otherwise your contributions are useless.
The target market for these amps are satisfied with the comprehensive datasheet of the SIL-994, the measurements that have been presented, and the sound that they hear. Only a complete idiot would assume a tiny silicon chip would sound identical to the SIL-994. It's not the same thing in disguise.
Can we perhaps try to have a civilised discussion without pejoratives?
There are indeed reasons a tiny silicon chip could perform better than a discrete circuit - sensitivity to noise and interference is one thing, parasitical capacitance and inductance another, both caused by the physical size and unavoidably longer interconnections of discrete components.
Write an email to Hypex them and tell them they are idiots for using discrete opamps in all of their flagship products then.
"All stages in the Makua use discrete amplifier modules"
http://mola-mola.nl/index.php/ct-menu-item-2
"The input stage is moved to a separate circuit board that uses the same discrete buffers as those found in the Makua"
http://mola-mola.nl/index.php/ct-menu-item-3
http://mola-mola.nl/index.php/ct-menu-item-2
"The input stage is moved to a separate circuit board that uses the same discrete buffers as those found in the Makua"
http://mola-mola.nl/index.php/ct-menu-item-3
"De ja vu all over again". How many times have we gone through this same discussion? Statements don't become facts just by repeating them over and over.
I guess that was too much to hope for.
So you're saying Hypex doesn't really use discrete gain stages in their flagship Mola Mola line? It's not true that the onboard LM4562 based buffer on the NC1200's are bypassed and an external board based on a discrete opamp is used instead with the Kaluga?
Bel Canto does the exact same thing with their $50000 Black system. They use discrete buffers with the NC1200's. But on their budget $5000 NC500 based monoblocks, they use an IC opamp based buffer.
It's awful strange that you usually find discrete circuits used in the highest end products, and IC's used in the low end products. Everyone must have it backwards. If I were you I would arrange a hate group to picket in the streets in front of these manufacturers main headquarters until they get it right.
Why would I say that?
Several of us have suggested non-performance reasons to use discrete circuits (as you well know).
Not strange at all. The "highest end" is very much about perception and marketing.
The hyperbole and straw man show is not really helping to further your argument.
The thread is re-opened, for those that want to discuss alternative input/buffer boards and what-nots, please start your own thread(s) - do not hi-jack this one.
Some pretty outlandish accusations have been made recently which might give concern to purchasers of a Nord NC500 amp with the Hypex recommended buffer circuit including the LM4562. However, once again, Section 11.2 of the NC500 data sheet provides a lot of information useful for those speculating as to the output current required from the necessary buffer (whether using one provided by Hypex according to their recommended design or any other circuit design even if none of the latter have been proposed by anyone thus far). More specifically, it states "use the model of Figure 2 to estimate input current." It takes about five minutes to model this in LTspice. The results are straightforward and conclusive and should provide comfort for those wanting to use the Hypex buffer or the Nord buffer with an IC op amp.
I think (hopefully) we can all agree that the higher the line input voltage the greater the current the buffer needs to supply. So for huge conservatism's sake, let's drive it with a whopping 4Vpeak differential input voltage (2.83Vrms) i.e. 2Vpeak on each input. This implies a swing in the voltage output from each of the op amps to about 10.8V or a swing in the output differential voltage from the buffer to about +/-21.5V. See pic 1. (I don't even need to convert that to SPL at my listening position given my speaker efficiency and listening distance to know I'd quickly go deaf.)
Now, let's look at the output current of each of the two op amps. Pic 2. A glance at the model and it is easy to see that the loads are different for each. But more importantly for those that fear their buffer with an LM4562 or other IC op amp can't provide the output current, we can see that even with this massive input voltage the most demanding current output is 23mA. I guess if you play your NC500 above its absolute maximum all the time you might get concerned the LM4562 is operating at the maximum of its specified range. I wouldn't though. And I wouldn't drive the NC500 to such levels in the first place.
If sonic differences are audible when one changes the IC op amp or deploys a discrete op amp design I don't think it's because the IC op amp is being demanded more current than it can provide.
I think (hopefully) we can all agree that the higher the line input voltage the greater the current the buffer needs to supply. So for huge conservatism's sake, let's drive it with a whopping 4Vpeak differential input voltage (2.83Vrms) i.e. 2Vpeak on each input. This implies a swing in the voltage output from each of the op amps to about 10.8V or a swing in the output differential voltage from the buffer to about +/-21.5V. See pic 1. (I don't even need to convert that to SPL at my listening position given my speaker efficiency and listening distance to know I'd quickly go deaf.)
Now, let's look at the output current of each of the two op amps. Pic 2. A glance at the model and it is easy to see that the loads are different for each. But more importantly for those that fear their buffer with an LM4562 or other IC op amp can't provide the output current, we can see that even with this massive input voltage the most demanding current output is 23mA. I guess if you play your NC500 above its absolute maximum all the time you might get concerned the LM4562 is operating at the maximum of its specified range. I wouldn't though. And I wouldn't drive the NC500 to such levels in the first place.
If sonic differences are audible when one changes the IC op amp or deploys a discrete op amp design I don't think it's because the IC op amp is being demanded more current than it can provide.
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I'm waiting for delivery of OPA1612 to find out how it will behave + will try to boost supply to 15V to give opamps some spare room to breath, will confirm back my findings once done...
I am not sufficiently technically minded enough to know if Bavmike is right or wrong with his thoughts but it cannot be denied that he has made some valuable contributions to this thread.
Without his input the Nords would probably not now be available with Rev. C boards and SI op amps. Which again in my opinion sound superb.
In my opinion Mike is a decent bloke trying to help get the most from hi fi equipment and help others do so. As far as I know he is also Canandian who are very friendly people as I have found on many ski trips to Banff and Whistler.
3lviz has also done some great research into op amps suitable for use with the Nords and should also be commended I believe he has also found the Nords with Rev C boards and SI op amps to be the best combination so far.
Boggit has done a great job bringing this product to us and making it available with great sounding buffers and op amps to suit everyones taste.
I feel with the options available we need never buy another amplifier just change the op amp to suit our taste and rest of system components.
Without his input the Nords would probably not now be available with Rev. C boards and SI op amps. Which again in my opinion sound superb.
In my opinion Mike is a decent bloke trying to help get the most from hi fi equipment and help others do so. As far as I know he is also Canandian who are very friendly people as I have found on many ski trips to Banff and Whistler.
3lviz has also done some great research into op amps suitable for use with the Nords and should also be commended I believe he has also found the Nords with Rev C boards and SI op amps to be the best combination so far.
Boggit has done a great job bringing this product to us and making it available with great sounding buffers and op amps to suit everyones taste.
I feel with the options available we need never buy another amplifier just change the op amp to suit our taste and rest of system components.
But you won't believe those of us who are technically minded enough?
I am sure he is, but that has no relevance to the validity of his claims, and it definitely isn't relevant to the topic of this thread.
Voltage regulators normally run warm to the touch, even when the circuit on their output is idle. The regulators are often the warmest parts in any small signal application, such as a line buffer. I'm astonished that so many posts were made without anyone stating explicitly the obvious: the 60mA figure includes heat dissipated by the regulators. There were several attempts made to explain that it was total current for the board, but those arguments drowned in the general noise -- which was frankly shameful.