Ncore - click from case

careful with that soldering iron, Eugene
User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Ncore - click from case

Postby David H » Tue Apr 25, 2017 12:46 pm

I built two NC400+SMPS600N400 amps back in December 2015. I used Silicon Ray cases. They still work perfectly as amps.

Recently, about 10 seconds (I've not timed it but it seems consistent) after power up, one of the amps always produces a single click. This is not through the speakers; it is more like a mechanical relay click from the amp case.

Any ideas? I have contacted Hypex but in the meantime I just wondered if anyone else had experienced anything similar.

robt2379
CU Subscriber Member
CU Subscriber Member
Posts: 68
Joined: Fri Jul 03, 2015 5:41 am
Location: Hampshire

Re: Ncore - click from case

Postby robt2379 » Tue Apr 25, 2017 4:43 pm

When I switch my Nord Ncore on, there is a delay of about three seconds before some kind of relay switches with a click and the amp comes on. Likewise, there is a mechanical click when I switch off.

Perfectly normal operation I'm sure.

Rob

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Tue Apr 25, 2017 8:49 pm

Thanks. Yeah, what you describe is perfectly normal. Mine did that until recently when there was an additional louder click after a good ten seconds.

I've taken the offending amp apart and found what looks like a faulty capacitor on the SMPS. I've sent photos to Hypex

I received a really quick, friendly response to my email earlier today. We'll see what they say when they get the photos.
Attachments
2017-04-25 21.57.03.jpg
2017-04-25 21.57.03.jpg (191.06 KiB) Viewed 903 times

robt2379
CU Subscriber Member
CU Subscriber Member
Posts: 68
Joined: Fri Jul 03, 2015 5:41 am
Location: Hampshire

Re: Ncore - click from case

Postby robt2379 » Tue Apr 25, 2017 9:22 pm

Yep, something definitely fried there!

Lets hope Ncore do the right thing and replace for you.

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Wed Apr 26, 2017 2:53 pm

Hypex are being hyper helpful:

"That’s an inrush limiting resistor. It looks like it failed due to mechanical damage. We can replace them on both supplies under warranty."

But I've asked for a part number so I can just replace them myself without having to send them back to Holland. Through-hole components, so it's an easy fix. :)

robt2379
CU Subscriber Member
CU Subscriber Member
Posts: 68
Joined: Fri Jul 03, 2015 5:41 am
Location: Hampshire

Re: Ncore - click from case

Postby robt2379 » Wed Apr 26, 2017 4:50 pm

Good news.

Things can and do fail, good to know that Hypex are making the right noises. Just what we want to hear from them. Let us know how it gets resolved.

User avatar
ozzric
Full Member
Full Member
Posts: 124
Joined: Sun May 15, 2011 11:24 am
Location: South Norfolk

Re: Ncore - click from case

Postby ozzric » Thu Apr 27, 2017 2:26 pm

Its a standard VDR (Voltage Dependant Resistor) designed to protect the PSU from surges.
The resistance decreases as the input voltage goes up and are ideal for preventing spikes on the mains from the fridge etc from affecting the circuit and coming out as clicks from your speakers (Ironic that the fault condition was clicks) :) They are typically connected between Live and Neutral on the incoming. The mains spikes/surges are partially absorbed due to the resistance of the VDR, but most is simply shunted to the neutral line.
Usually if one fails like that, it has been subject to a sustained surge, however it looks like Hypex have identified a bad batch.

The amp will still work perfectly well without it if you can't wait for replacements it can simply be removed from circuit. Don't do it if you are expecting a lightning strike :)

Anyhow great that Hypex are furnishing you with replacement components. Failing that they are readily available from RS, Maplins etc for a couple of pounds.

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Thu Apr 27, 2017 5:51 pm

Thanks ozzric. Interesting.

I didn't want to send my kit back to Holland. So I just ordered from RS @ £1.60 each (using part number supplied by Hypex) and have replaced the components. Not had a chance to connect them up to the speakers yet - still at work :(

As you can see, my electronics knowledge is very poor. Can you explain why this component is a thermistor? Given my ignorance, that suggests to me that the SMPS 'protection' is temperature dependent.
Last edited by David H on Thu Apr 27, 2017 6:04 pm, edited 1 time in total.

User avatar
mickbald
Addicted
Addicted
Posts: 1058
Joined: Wed Aug 06, 2014 10:01 pm
Location: Shropshire

Re: Ncore - click from case

Postby mickbald » Thu Apr 27, 2017 6:01 pm

See David, if you'd specified gold plated thermistors and other special stuff like they use in them upgraded fuses you would have had no problems and better sound quality.

Only £160 a "pop".

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Thu Apr 27, 2017 6:11 pm

Yeah, Mick. My bad. ;D

Hijacking my own thread...on an embarrassing but honest note, I have to admit that I have recently benefited from a definite improvement in the high frequencies from my speakers since upgrading to some Ixos speaker cable supplied to me by Chris. Single bind testing gave a significant correlation. And I am on record as quoting "only Ohms law applies" :-[

I am still a long way from spending £160 on a gold-plated fuse but I will try to open my mind a little more. That was sage advice once offered to me here by the very wise IanS1.

callen24
Addicted
Addicted
Posts: 2911
Joined: Wed Jun 15, 2011 9:39 am
Location: lesta

Re: Ncore - click from case

Postby callen24 » Thu Apr 27, 2017 6:42 pm

David H wrote:Yeah, Mick. My bad. ;D

Hijacking my own thread...on an embarrassing but honest note, I have to admit that I have recently benefited from a definite improvement in the high frequencies from my speakers since upgrading to some Ixos speaker cable supplied to me by Chris. Single bind testing gave a significant correlation. And I am on record as quoting "only Ohms law applies" :-[

I am still a long way from spending £160 on a gold-plated fuse but I will try to open my mind a little more. That was sage advice once offered to me here by the very wise IanS1.

Surely its the weave, and third strand removing RF?
cyrus stream X2, CDi, Oppo HA-1SE, IMFs, mfa Baby classicV2, Mono X300,  VA Beethoven Baby Grand
ML binarystar digital, DenchXLR, RFCneptune RCA, VanDamme OFC spk cable. AG 500 ac regenerator and Townsend Seismic sink stand.
rega P3-24, psu, AT95e/paratrace, Clearaudio nano, Project RCM

User avatar
ozzric
Full Member
Full Member
Posts: 124
Joined: Sun May 15, 2011 11:24 am
Location: South Norfolk

Re: Ncore - click from case

Postby ozzric » Thu Apr 27, 2017 7:11 pm

Can you explain why this component is a thermistor? Given my ignorance, that suggests to me that the SMPS 'protection' is temperature dependent.


A thermistor has a high value when cold, when it warms up the resistance decreases. They are used in PSU's to limit the inrush current at the point of power up to prevent damage to rectification components.
They can also be used in circuits to determine temperature, whereby the resistance determines the speed of a fan or a detection of a temperature threshold for instance.

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Thu Apr 27, 2017 7:50 pm

ozzric wrote:A thermistor has a high value when cold, when it warms up the resistance decreases.

Thanks. I guess that's negative temperature coefficient (NTC) thermistors. I think I understand the use here now - the NTC thermistor limits the current when it's cold, at power on to prevent a potentially damaging current surge. Then as it heats up, its resistance reduces allowing higher current to flow into the SMPS. Is the heat caused by the current flow through the thermistor itself?

I've only ever used thermisotrs for sensing temperature - heat alarms, etc. Forever learning...

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Thu Apr 27, 2017 7:55 pm

callen24 wrote:Surely its the weave, and third strand removing RF?


It might be the fact that it's a twisted pair, yes. But the third strand is passive - just solid plastic to allow the two copper wires to plaited. Anyway, thank you.

User avatar
David H
Sr. Member
Sr. Member
Posts: 439
Joined: Sun Nov 10, 2013 11:38 pm
Location: Leics UK

Re: Ncore - click from case

Postby David H » Thu Apr 27, 2017 8:01 pm

OK, amps back in and everything working well. :) I'm a happy bunny again.

Hypex support was excellent. Email response was within minutes from an engineer. Really practical help offered rather than the usual 'official line' given out automatically by some companies. They offered to repair both power supplies and gave me RS part numbers giving me the option to repair it myself without the cost, hassle & delay of return postage.