Opening a NAP200

I bought a used NAP200 that occasionally trips the circuit breaker when switched on. Not only that but it puts quite a pop through my speakers.
It is definitely no longer under warranty (Serial No.: 251614) and I want to put in a soft-start circuit (DIYaudio) to stop the inrush current from doing any permanent damage. Question is, how do I open the thing. There are 5 hex screws in the base. I can assume the one standing off on its own is the large transformer. NAP200 from the bottomCould someone help me out here? 

Original Post

I don’t think altering anything inside the amp is going to help. In a UK mains circuit, having the MCB changed from Type B to Type C is likely the best solution. Not sure what your location is, but you might ask an electrician if this could be done for your supply. 

NAP200 & most other power amps will always pop the speakers, especially if you don't power them off & on correctly.  And if you are turning it on & off a few times they will always trip the MCB every once in a while.  Plus - BIG PLUS - as you are in Austria the power circuit design is completely different to the UK system that a lot of forum members are used to.   Your Moeller B16 is rated at 16 amps & as such is far more liable to trip compared to a UK specification ring main power circuit with 32 amps.  You could change to a C16,  or even go to C20,  consult a professional electrician on that. 

As per previous post,  Naim units are designed to be left powered up 24/7.   OK to turn off for longer periods such as a week or holidays when you are away,  also electrical storm conditions.   

It's not cost savings but ecological consciousness. What if everyone turned their devices off when not using them? Call me a treehugger, I wear it with pride.
I don't mean to be contentious; I appreciate the advice and will look into upgrading the MCB as suggested.

@Mike-B What is the right way to power it on and off?

patoperro posted:

It's not cost savings but ecological consciousness. What if everyone turned their devices off when not using them? Call me a treehugger, I wear it with pride.
I don't mean to be contentious; I appreciate the advice and will look into upgrading the MCB as suggested.

@Mike-B What is the right way to power it on and off?

Mike is referring to the standard on/off sequence. Power amp off first and on last, and you won’t go wrong. 

I don’t disagree with the need to reduce our energy use, and we have all led bulbs, a condensing boiler, use renewable electricity, cycle or walk wherever possible, etc, etc. But.... the Naim sounds so much better when it’s left on all the time that it’s a compromise I’m willing to make. Driving a bit slower or taking a walk instead of driving saves vastly more fuel than turning off the amplifier. But of course, you know that, and we can all do more. Try leaving it on for a week and see if your enjoyment of your music increases: you could always listen in the dark to compensate!!

I have a C20 MCB from Siemens (5SY4) on my dedicated circuit and it has never been tripped so far. Assuming the circuits in Austria and Germany are similar, this or a similar product might be the solution. But, as always when it comes to AC circuits, ask your electrician.

patoperro posted:

It's not cost savings but ecological consciousness. What if everyone turned their devices off when not using them? Call me a treehugger, I wear it with pride.

And so you should. Ecology is not a joke.

But I think it is more complicated than that. Turning things on and off constantly has a larger environmental impact in the long run. As electronic products (even the best made ones) are far more likely to develop a fault on power on, mathematically, your odds of having a fault on a product multiply for each item you do this for.

And when an item does fault, the impact of the shipping to and from a place of repair or the impact of a manufactured replacement is greater (as is the cost - but you already said that was of no concern to you) than the impact of having the unit powered on all the time.

Let us say you have a 5 box Naim system and each unit has a 10% chance of failing in a 10 year period if powered on and off twice a day every day. Probability is calculated as ratio multiplication so you would have a 50% chance of a box in a 5 box system faulting in 10 years. The result of that fault is transport by various vehicles to Naim and back, the manufacture of replacement parts, and or the manufacture of a whole new unit. Both the monetary cost and environment cost are likely to be far larger than the cost of the idling current of the units left on 24/7.

Of course, you can power them on and off every day and they might march on for 40 years without a problem. But if the same power off policy is used throughout the home, you won't beat the odds forever and it becomes more of an environmental issue with lower cost, more modern, very lower power consumption devices that are not built to the same standard as Naim. Low cost, low power domestic appliances have a very bad ratio of energy consumed when idling against the energy cost incurred for repairing/replacing a failed unit. Ideally, you want things to be as energy efficient as possible and to use them in a way that then makes them last as long as possible to reduce the demand for related logistics and the manufacturing chain.

i thought we were also all fkkd because America runs big engine cars and the Chinese  run high emission industries. As we don't really have any industries left in the UK now

We are less to blame these days...but sadly when we did have industries , they disregarded the future and polluted our planet beyond belief/???

Simple observation regarding changing a 16A CB to a 20A device.

The sole purpose of the circuit breaker  (or fuse) is to protect the wiring not the load!

Only change from a 16A to a 20A if you are certain all of the down stream wiring will coordinate with the 20A CB. 

Changing from a type B to a type C will not impact the wire protection.

Paul. 

@feeling_zen I know the impact on consumption is small, but I turn the unit off and on maybe once a day, if at all. A year later, it's still going strong (had my used Qute for 5 years even), so I'll keep rolling the dice. I bought the unit used for 700 Euro and if it broke (depending on what breaks, of course) I'd probably not send it back to Naim for repair, as I understand it's quite expensive to do so, but shop around for another used one. That's the great thing about the advance of technology; there's always someone out there who has to have the latest, feature-rich model (the person I bought my NAP 200 from wanted to buy the DR version).

Thanks for adding that @PAUL CA

@SJW, not taking the bait. I'm taking a break from online political discussions of all kinds for a while. Gotta reserve my energy for 2020  

I've had to dig out our old 200 for use whilst we get some other items serviced. It hadn't been used for maybe 5 years.

For the first 2-3 days it sounded thin but now, after 6 days the sound is much more integrated. Maybe some of this is me getting accustomed to the altered mix but I'm pretty sure that thermal stabilisation is the main issue.

@ OP: Why not try leaving yours on for a week - I'm sure you'd notice a performance benefit.

Sorry but the suggestion to swap a b type mcb for a c type on an existing circuit  is just outright dangerous.

There are tests that need to be carried out in the circuit to make sure a c type would be suitable.

its all very well not being allowed to discuss diy mods on people’s own equipment on the forum but why is electrical work allowed when it can be just as, if not more hazardous?

@JASONS I understand that this is something I cannot undertake myself and I would naturally consult the electrician before asking him to come out and swap out the MCB. The NAP200 and Qute, TV, wii and media player are the only things downstream of this particular MCB. What sort of dangers are you referring to exactly?

jasons posted:

Sorry but the suggestion to swap a b type mcb for a c type on an existing circuit  is just outright dangerous.

There are tests that need to be carried out in the circuit to make sure a c type would be suitable.

its all very well not being allowed to discuss diy mods on people’s own equipment on the forum but why is electrical work allowed when it can be just as, if not more hazardous?

Jasons, members can discuss electrical installations, but only so long as it complies with whichever electrical code applies for wherever they are situated.  In all cases, members should at the very least, consult with a fully qualified and certified electrician familiar with the electrical code for their country and area.

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