hypex ncore

[troystg]

Originally Posted by jmbulg

Or replace the power on/off switch by three switches, one for each SMPS you then turn on one after the other.

Or add two different RC networks on the AMPON lead to delay the start of two amps.

[waltzingbear]

Originally Posted by troystg

Or add two different RC networks on the AMPON lead to delay the start of two amps.

after you add the transistor to pull the Nampon lead to gnd for remote turn-on.

But really, has anyone measured the turn-on current for the SMPS600 or ncore? At first blush it doesn't seem likely that 3X should trip out a 16 amp breaker. What is the time sensor on this breaker, ie slow blow or fast blow?

Alan

[RogerSch]

My case switching on 4 SMPS600 the circuit breaker didn't trip but with 5 it did.

You could try to solve the tripping of the circuit breaker with a circuit breaker with a different Instantaneous tripping current. In my home I have B-type circuit breakers (see link: Circuit breaker - Wikipedia, the free encyclopedia). I considered type replace it with C-type circuit breakers which have a higher Instantaneous tripping current. Please check if your national (or local) electricity standards allows other type of circuit breakers!

In the end I choose for this solution: Unitec 41748 Inschakelstroombegrenzer Zwart in de Conrad online shop (Sorry for the dutch). It limits the inrush current when switching on the amps. It works great. Here is also a link to the German Amazon website: uniTEC 41748 Einschaltstrombegrenzer: Amazon.de: Baumarkt

[pieter t]

Originally Posted by RogerSch

In the end I choose for this solution: Unitec 41748 Inschakelstroombegrenzer Zwart in de Conrad online shop (Sorry for the dutch). It limits the inrush current when switching on the amps. It works great. Here is also a link to the German Amazon website: uniTEC 41748 Einschaltstrombegrenzer: Amazon.de: Baumarkt

But another investment to get your amps up and running.
Wouldn't simple good value NTC resistors at the input of the SMPS600 do the same ? (would not be surprised if these "inschakelstroombegrenzers" work with NTC resistors as well, but not sure of that)

[RogerSch]

Originally Posted by pieter t

But another investment to get your amps up and running.
Wouldn't simple good value NTC resistors at the input of the SMPS600 do the same ? (would not be surprised if these "inschakelstroombegrenzers" work with NTC resistors as well, but not sure of that)

Yes these work usaully with a NTC resistor. Some of these "inschakelstroombegrenzers" uses a relay to bypasses the NTC after a few seconds.

[ajst2duk]

Would it be safe to short the outputs with the Nampon disabled? In other words is the output device off with Nampon not pulled to ground?
I ask this because I'm wondering whether to add power-on switch which simply pulls Nampon to ground. If the amps had power - but were switched off in this manner would it be safe to connect/disconnect speaker leads without fear of shorting?

[waltzingbear]

Well Souldriver showed us a few days ago that shorting the outputs causes no immediate harm after he built his with both speaker connectors connected to the chassis.

I'm sure he ran his for a multiples of minutes.

In other words, not a major concern. In fact,with most amps today, you should (with no signal running) be able to short the outputs without concern. Not recommended however. Think of it this way, with no signal, there is no power being supplied. If it can't be shorted, its a bad design.

Alan

[Bruno Putzeys]

Random answers:

Y: I try to minimize Y caps but there still is some. It's less than what a similarly sized toroid has in terms of interwinding capacitance, but it's still enough to feel the leakage current. Interestingly, the SMPS600's leakage current is still well below what is permissible for medical gear (which gives pause for thought...)

Inrush: We'll see what we can do. It should be possible to reduce the inrush current of the SMPS600 because there already is the equivalent of a softstart on board (albeit with a fairly low resistance). If it's easily retrofitted we'll post instructions.

Disable: The output goes high z (is completely turned off) when nampon is off, so they're entirely safe. Actually the protection insures you're also safe even when the amp is operating, but from a psychological point of view I can easily see why one would feel better turning the amp off.

[Juhleren]

Originally Posted by Bruno Putzeys

Random answers:

Y: I try to minimize Y caps but there still is some. It's less than what a similarly sized toroid has in terms of interwinding capacitance, but it's still enough to feel the leakage current. Interestingly, the SMPS600's leakage current is still well below what is permissible for medical gear (which gives pause for thought...)

Bruno,

I guess that you compare to a "standard" toroid as one with internal shielding and other trafo types like R and C cores can have much less capacitive coupling between primaries and secondaries.

- Or are you primarily talking of "interwinding" as in between the windings within e.g. the primaries?

Have you found the Y capacitance to audibly and/or measurably affect the performance of the SMPS´s? -I guess that you strive for a low value for a good reason

cheers,

[Bruno Putzeys]

I was only talking about the primary to secondary capacitance, which does the same as a Y capacitor. Internal shielding doesn't help there, but R cores are much better of course - in that respect at least.

The Y capacitance is not an issue when using normal balanced wiring, AES48 style. But in all-RCA rigs with no form of floating or differential input you can't connect the safety earth as any ground loop will go on to cause trouble. Under those conditions, all leakage current will circulate through the signal connection so the leakage current had better be small.