Switching on NAP 250DR using front panel button causes power to trip

The PS Audio mains regenerator is essentially a class A power amp playing a 60Hz wave at full output. This must considerably adding to the net power consumption and probably is the ultimum paleas. If you were to try the system without the P10, the power trips probably would not exist. 

I tried a PS Audio Power Plant with a 552 and a CDS3, and did not care for the restricted sound it produced. It was however an excellent power source for the Armageddon, where it provided a noticeable improvement in the LP12's performance compared to direct mains connection. 

Have you tried a direct-to-wall socket connection witht your Naim gear? The fact that the P10 appears to be limiting current draw to avoid tripping in some instances, suggests that it may be limiting current during music replay too. 

Hello Ron, thanks for your reply. No I haven't tried a direct connection yet, but you've certainly given me something to think about!

Cheers!

I had a similar issue with my NAP250DR tripping the 16 amp type B MCB in my consumer unit on power up. After consulting a qualified electrician the type B MCB was replaced by a 16 amp type C MCB (which requires a slightly higher current load before tripping than the type B) and this has cured the problem.

Suggest you consult a qualified electrician to check whether this solution would apply to your situation.

Hi SingSlinger,

I assume you mean the it's tripping the MCB (breaker that protects that circuit in the house from overcurrent states), rather than the RCD (also known as an Earth Leakage Circuit Breaker, that protects against earthing faults and electrocution).

If so then you may be using too fast an MCB (try using a Type 'C' MCB instead of a Type 'B' one).
If you already have a Type C, then you need to discuss with an electrician as although type D are available, they are specialist devices and shouldn't normally be used in domestic installation.

The reason this happens is that the massive transformer and large capacitors in a 250 require an enormous, but very short term, 'inrush current' when the power is first applied and the PSU is charging up the capacitors.  This can trip the MCB even though the continuous current demand is hundreds of times lower than the inrush current.

if you plug the 250 into a normal wall socket, what happens?

if it is ok, but only has this "feature" when plugged through the mains generator, then it indicates that the mains generator is freaking out. Which is suboptimal.

Jon, actually it's quite normal for a mains regen to "freak out" when faced with a sudden high demand like that, it is bound to take it 'out of regulation' and the three (or two) term controller will then try to restore normal operation.  The question from the point of a regen is how quickly it settles back into regulation, and how good that stable state is.

Incidentally for any regen there are some active loads that it'll never be able to stabilise, and there is a small chance that this could be the cause here.

But yes, plugging it into the wall is likely to answer the problem and is quite likely to improve the SQ at the same time!

Yes, I had this problem with a 250 also (never with its predecessor 200) and it was cured by plugging the 250 (now DR) directly into a double wall socket and leaving the other socket unused – merely a lamp in the other socket results in a trip when the 250DR is switched on.

Huge posted:

Jon, actually it's quite normal for a mains regen to "freak out" when faced with a sudden high demand like that, it is bound to take it 'out of regulation' and the three (or two) term controller will then try to restore normal operation.  The question from the point of a regen is how quickly it settles back into regulation, and how good that stable state is.

Incidentally for any regen there are some active loads that it'll never be able to stabilise, and there is a small chance that this could be the cause here.

But yes, plugging it into the wall is likely to answer the problem and is quite likely to improve the SQ at the same time!

Indeed. Which is why I view them as marginal at best. And a very expensive way of claiming to fix a problem which the user doesnt understand, by replacing one thing with another set of issues

Id like to think that a NAP250 is a pretty simple load with a low crest factor. I could measure this, but my 250DR is in the listening room on another site, and the Newtons4th power meter is here. Another time...

I suppose if the OP prefers the SQ of the amp running off the P10 then using it as he does with the P10 doing the switching will be best and cause no harm.

As it's Naim, I can't help thinking the whole system would be better connected straight to the mains...

Except the OP admits he has not tried the system without the mains regenerator....which surely must be the next logical step. 

I had this problem with 555PS's. The solution, as mentioned above a couple of times, was to change the MCB on this spur to a slower blow one.  I advise you to consult a sparks, he'll know what you're talking about... if not, find a sparks who does !   The cost should be minimal, but the effect will be a permanent cure 

I would check the circuit breaker... I had this some time back... it was a faulty circuit breaker... they can go faulty apparently after tripping from a surge from lightning etc.

The other thing that can trip them is when there is earth leakage, not enough to trip it, but when vombined with surge from powering up the transformer can make it trip.

Either way I'd get a sparky to check... I suspect if the Naim device was faulty it's fuse would pop.

S 

My Armageddon used to trip the HiFi spur until I upped the rating of the MCB to 32A. Sometimes the MCBs can simply be a little over-sensitive. I wonder what would have happened to 'Doc's' mega PA system in B2TF if he had used MCBs? And if the flux capacitor had tripped out on the lightning strike!