[EuroDriver]

+ 1 on the long warm up time

[gstew]

Ditto on the warm-up time... with most other equipment I've used recently, 1-2 hours is sufficient. The NC400's take about 5 hours to come on song for me... although one thing I noticed with the modified caps is that they are sweeter and more listenable during the warmup time than they were beforehand.

I found the break-in time to be much longer than what I've experienced with other equipment, over 2 months as I remember.

Greg in Mississippi

[Rclark]

 Also concur, amp does take some time to warm up, makes a noticeable difference.

And not surprised that the Ncore bests older tech. That's been a recurring theme since they were first introduced. a lot of expensive amps waylayed and set aside for Ncores. More often than not. And those in the "not" category,  you could see those guys opinions coming a mile away, so no surprises there either.

[Julf]

Mine are up to song straight away, and don't seem to change with warm-up.

[Rclark]

Mine are up to song straight away, and don't seem to change with warm-up.

I haven't noticed the overly long times described above, always seems to be about 30 mins or so for me, whether whole system cold or not. It's not like some ENORMOUS change though, they are always good no matter what. Warmup could be imagined, but is something ive noticed over a few years and several on/off/ons.

[rollo]

   Class "D"amps IMO should be on 24/7. After two days on they will sound better. The power supplies like being on and coming to operating temperature.
    Try it before burning me at the stake.


charles

[OzarkTom]

   Class "D"amps IMO should be on 24/7. After two days on they will sound better. The power supplies like being on and coming to operating temperature.
    Try it before burning me at the stake.


charles

+1

[Julf]

Class "D"amps IMO should be on 24/7.

That's quite a generalization considering the very different class D architectures and implementations out there. Any rational analysis as to why that might be?

[OzarkTom]

That's quite a generalization considering the very different class D architectures and implementations out there. Any rational analysis as to why that might be?

Because it sounds better. IMO, all SS amps should be left on 24/7 to get the best sound.

[Julf]

Because it sounds better.

No, it doesn't.

IMO, all SS amps should be left on 24/7 to get the best sound.

IMO that is not very good advice, because not only is it wasteful, but many components, such as electrolytic capacitors, have a limited lifetime in terms of operating hours. A typical design lifetime might be 20000 hours - 11 years of 5h/day use, but only a bit above 2 years at 24/7.

[OzarkTom]

No, it doesn't.

Maybe if you buy some reference speakers to go with your reference amp, you will hear the difference.

[Julf]

Maybe if you buy some reference speakers to go with your reference amp, you will hear the difference.

Ah, so my system isn't resolving enough?

[occamsrazor]

Hi Julf,

You posted this in the NAD M22 thread, but I'm putting it here as it is more relevant:

That runs counter to my experiences. I have a very noisy and unstable mains (some of the graphs introduce nausea), but my ncores (fed by smps600's) don't seem to mind. The fast and efficient feedback architecture of the nc400 seems to be able to correct out anything that makes it through the smps...

If you have time could you talk a bit more about this subject? I myself have horrible power fluctuations including wide fluctuations and long multi-hour power cuts, which I mentioned in another thread. I note you say your experience is that the NC400 can handle large voltage fluctuations.
I run mine using a surge-protector that also employs an under/over 180v/250v disconnect, which should at least keep them within the Hypex specs even if the mains voltage goes outside those parameters. However when the power is off my house runs from a modified sine wave (not pure sine wave) inverter.

So I was just wondering if:

a) You think it is still a good idea to use these surge protectors with the over/under cutoff?
b) Whether feeding the ncores a modified sine wave could cause any damage?

[Julf]

I myself have horrible power fluctuations including wide fluctuations and long multi-hour power cuts, which I mentioned in another thread.

Ouch! Not fun!

I run mine using a surge-protector that also employs an under/over 180v/250v disconnect, which should at least keep them within the Hypex specs even if the mains voltage goes outside those parameters.

Yes - the absolute maximum voltage is 270 V. There is no "absolute minimum" voltage, as undervoltage won't hurt the smps/amp, it just won't work as well.

a) You think it is still a good idea to use these surge protectors with the over/under cutoff?

Probably a good idea.

b) Whether feeding the ncores a modified sine wave could cause any damage?

I don't think there is much danger of real damage. The smps input filter will absorb a lot of the harmonics generated by the non-sine-ness of the inverter, so it might a bit warmer than normal, but as you would only be running on the inverter for a few hours at a time, it shouldn't be an issue.

[occamsrazor]

Ouch! Not fun!

Yes it's annoying. So far, touch wood, the whole-house surge protector has protected all my devices well and I've had no actual damage. Other people who don't use often do get blown devices.
The only device that had problems was my Audiolab MDAC, which freaked out (display flashing, wouldn't boot) when served voltage of around 200v. It was either the low voltage or the modified sine wave I'm not sure, but it sure didn't like it. I bought a voltage regulator and that fixed the problems with the MDAC:

http://www.tripplite.com/line-conditioner-1000w-avr-system-automatic-voltage-regulator-power-conditioner-ac-surge-protector~LR1000/

It employs similar cutoffs but anywhere within the "acceptable" range it stabilizes at 240v. I was wondering if I ought to plug the nCores into this as well but reading your comments and some others it seems that might not be the thing to do.

There is no "absolute minimum" voltage, as undervoltage won't hurt the smps/amp, it just won't work as well.

Really? Here everyone has to use protection against brownouts (extended low voltage) as it kills the motors in fridges, although I guess that's completely different. Wouldn't a lower voltage lead to a higher current than normal being drawn? So you think low voltage even over extended time won't cause any damage to the ncores? Low voltage is by far a bigger problem here than high voltage....

Thanks again, as usual your continued advice on this and other forums is very much apppreciated....

[Julf]

Yes it's annoying. So far, touch wood, the whole-house surge protector has protected all my devices well and I've had no actual damage. Other people who don't use often do get blown devices.

Fortunately for me the only real hassle is having to swap light bulbs pretty often.

The only device that had problems was my Audiolab MDAC, which freaked out (display flashing, wouldn't boot) when served voltage of around 200v. It was either the low voltage or the modified sine wave I'm not sure, but it sure didn't like it.

Probably the low voltage. Logic circuits can be pretty sensitive.

It employs similar cutoffs but anywhere within the "acceptable" range it stabilizes at 240v. I was wondering if I ought to plug the nCores into this as well but reading your comments and some others it seems that might not be the thing to do.

The line conditioner will limit surge current, and that might possibly restrict the peak current capability of the nCores.

Here everyone has to use protection against brownouts (extended low voltage) as it kills the motors in fridges, although I guess that's completely different.

Yes, motors stall if the voltage drops too much, and a stalled motor overheats.

Wouldn't a lower voltage lead to a higher current than normal being drawn?

Yes, but both the nCore  and the SMPS has current limiting, so there won't be any damage, just slightly reduced performance.

So you think low voltage even over extended time won't cause any damage to the ncores?

I am pretty sure you will be OK as long as you don't operate permanently below 180 V.

[occamsrazor]

Sound, sensible advice as usual. Thanks again.

[JayDoubleU]

Just a short note to add to this topic: have had my Merrill Audio Veritas amps for almost 6 months now. Absolutely the best I've heard, really a great amp! Leave it powered up permanently and music is ready to sound like never before. Or, well, just as magnificent as yesterday and the day before...