Newbie: Hypex NCore with push button

Hi folks,

I'm about to put together a Hypex NC400 stereo (either dual mono or a single SMPS1200A400) in a 2U case.

I'd like to put an LED push-button power on the front as it'll be in a rack. I was about to order the Hypex 24V button and their soft-start but read that they don't recommend this setup (although I see one on this build).

On alternative could something like this RS-online 250V switch.

Can anyone advise this newbie the best approach, please?
 
Okay... once again, it is not a smart plan to be switching SMPS on and off all the time at the AC inputs.

When the power is first applied there is a rather large inrush of current that can shorten the lifetime of the mains rectifiers significantly.

It is, thus, your best bet to leave the system (SMPS + AMP) powered up all the time and use the Hypex AMPON logic to switch the amplifier into standby as a pseudo on/off control.

The Hypex data sheet details this operation, saying that Grounding pin 3 of J9 enables the amplifier.
 
Class D might get a bit upset if the power supply comes up slowly.

Thanks Nigel. The SMPS has a soft-start built-in so I had assumed that would take care of proper startup.

Okay... once again, it is not a smart plan to be switching SMPS on and off all the time at the AC inputs.

Thanks Douglas. It's not obvious for newbie's given the Hypex kit version only has a power switch like this. Isn't it reasonable to assume the built-in soft-start accommodates this?

saying that Grounding pin 3 of J9 enables the amplifier

Thanks again. I'll look into this option although like others mentioned it's not intuitive to not power down devices fully, rather than just mute the output.
 
Hello Tim, My experience with Hypex did not use their power supply, so I grabbed a copy of the SMPS data sheet and I see that it does have provision to put the amplifier into standby during startup. It also has provision for SMPS standby. What is unclear (and 2 minutes with a multimeter would clear it up) is if the VAUX output remains live during SMPS standby.

If you can resolve that question, you may have a very simple way to enact the "soft-off" state which would put both the supply and amplifier into standby mode. You could take the VAUX to a small switch and current limiter to feed the SMPS standby pin. By further enacting the amplifier standby as they recommend you could achieve a very low powered idle state.

Take a look at the ratings, it lists Inrush Current at 37 amps which I suspect would be even higher with a live amplifier connected. This is not something you want to be a regular event.

Most commercial products these days are never fully off... your TV, AV Receiver, Computer, amlifiers, etc. all employ this technique and in general it is for the reason of avoiding those mass inrush currents.

For example: In PC power supplies, where I do most of my work these days, repeatedly turning off the "babysitter" switch on the back can cut a power supply's lifetime to half or less. The same is true of the laptop bricks, they die early when constantly plugged in and unplugged. I see no reason to expect this scenario to be any different.

Just keep that 37 amp inrush in mind.
 
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Thanks Douglas for taking your time to share your knowledge.

What is unclear (and 2 minutes with a multimeter would clear it up) is if the VAUX output remains live during SMPS standby.

For anyone reading this, it does not. You need a separate power supply for it. I see commercial builds of this use a separate SMPS - something like this would work I believe.

Again, for anyone stumbling on this thread, I asked [email protected] if the softstart in front of the SMPS was an option and they responded with:

The soft start would work perfectly fine for this purpose. That way you can use a non-latching push button with LED.

If you also require a mute switch you can wire one in series with the amplifier enable wire. But best just switch the complete unit off when not in use.

Thanks all
 
Thanks Douglas for taking your time to share your knowledge.

No worries...


If you also require a mute switch you can wire one in series with the amplifier enable wire. But best just switch the complete unit off when not in use.

Ahem ... 37 Amps...

You could leave the power supply on and use the AMPON from the audio section as I originally suggested.
 
Excuse me if I reply to an old topic but I have the exact same question, and I did not see the full answer to the op question. How did you do it in the end and do you have some pictures or a wire diagram?

I'm going to build 1 unit powered by an smps3ka700 and 1 by a smps3ka400 (about the same unit)

Should I shut the unit completely down and just cut off the main power cable, with the button itself or a relay, or put the unit in standby mode? It still consumes quite some energy, not sure if I'm a huge fan of burning energy without reason? (Other than doing a workout off course, but that's not really related)
 

RogerSch

Member
2010-09-26 10:59 am
I'm using 5 NCore amps, with their own SMPS power supplies, from april 2012 onwards and they are being switched off at the power supply when the surround equipment is not being used (on average three times a day) by a 12 volt controlled power relay. No problems at all until now. To protect the mains circuit breaker, when the 5 amps are being switched simultaneously, I'm also using an inrush current limiter.