300DR powering down by itself

Hi there,

My system is NDX2/252/SCDR/300DR and I am finding that if the system is left with no input or on very low volume the 300DR powers itself down.

It can’t be turned on by recycling the power on the 300 PS unless I wait 5 mins and then it will turn on again.

At higher volume (7 to 8 o’clock) the system is fine.

Any ideas?

When you say it powers down, what happens - do the logos go off (on PS and or head unit) or do you just get no sound ?. Is the 300 head unit warm or can you hear the fan running when it powers down ?. What cables are you using and how long are they ?

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Lights go out on both ps and amp. Using 2x5 meters Black Rhodium Foxtrot to speakers. Standard supplied Burndys, standard xlrs. Unit isn’t warm and no fan running.

Very strange although this does sound like the thermal cutout switch in the 300PS may be triggering for some reason - the logos going off and then the amp not being able to be switched on for 5 mins seems suspicious. If you leave it alone, does the amp power back up on its own after a few minutes ?

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The speaker cables don’t look like NACA5 to me…

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Yes it does.

Correct. They are 2x5 meters of Black Rhodium Foxtrot to the speakers.

Try to borrow some naca 5 from the dealer ( or chord) to see if the problem comes from the cables.
If not, I would return it to Naim.

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It could be the cables, but the OP mentions that the amp is not getting warm. Has this only just started happening or has it been doing it for a while - did it co-incide with a change in the system (ie new speakers, cables ?)

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@marka I have the same system, it’s never happended to my 300DR, I would recomend a return to NAIM to check out the PSU? on the 300

sorry not much help

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The cables are probably not a great match for a Naim power amp, but I find it hard to imagine they would cause an idle amp to shut down. It’s always worth comparing them with NACA5, but I don’t think it’s relevant to this problem.

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Is the power switch latching OK?

Otherwise, it sounds like the protection is cutting in for some reason. Are there any shorts in the speaker cabling. Trying some different cabling is worthwhile (if you have any standing by) just to check and see if that’s the issue here. Otherwise… ask your dealer to check it out.

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Yes it coincides with me replacing my 282 and 250DR. I traded them in for a brand new 252 and a brand new 300DR and at the same time bought the Fraim support.

I used the same speaker cables on the 250DR for 9 months and haven’t had any issues. Just good sound. I didn’t even lift or move the speaker cables significantly during the upgrade.

Black Rhodium Foxtrot are :

  • 2 core twisted pair loudspeaker cable
  • Diameter of cores 5mm
  • Capacitance between conductors for 3m length 83pF
  • Terminated in gold plated Z plug

I’m running a 5M length.

NAC A5 is about 20pF per m right? So The Black Rhodium Foxtrot are a bit thicker and do have a bit more capacitance, but I had no compatibility problems with the 250DR as I said, so is the 300DR more sensitive to higher capacitance cables?

As regards the power front, yes the AC inlet plug is securely inserted into the PSU and yes the power button on the PSU appears to latch ok. (Also - I only use NAIM Powerline Lite on the entire system).

Here is a more complete description of what I’m seeing happen:
The power down / cut out doesn’t happen at listening volumes, only at back ground volumes.

It first manifested itself when I decided to leave the system running over night playing radio paradise as a means to get hours on the new amps at low volumes.
And when I came down stairs the next morning, both NAIM badge lights on the PSU and AMP modules of the 300DR were off, the power button on the PSU was still on.

I then switched it off, and tried power recycling it, and it didn’t turn on. Thinking that I’d not fully inserted the AC inlet plug, I wiggled it and pushed against it harder. I then tried to power up the PSU and it turned on and I set it to low music again.

After 10 or so minutes of playing music at low background levels, I heard a pop and the AMP and PSU again turned off. Turning them off and waiting over 5 minutes and then turning it on, started it again.

Keeping the volume at low levels, a few minutes later it will turn itself off again.

If I turn the volume up on the pre-amp, its totally fine and continues to play for hours no problem.

In terms of the quality of sound, it’s excellent. Full bodied, good bass definition, great timing and superb detail. I can’t ask for more on that front.

Hmm - something is clearly not right. As you’ve checked everything else out i’d get your dealer involved and get the 300 checked out. There was something similar mentioned here a while back with a 300DR. I’ll have a quick search…

Here you go https://community.naimaudio.com/t/new-amp-little-concern/4462

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I would take it back to the dealer you got it from, as it sounds more like a problem with the unit than anything else

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Another thing to check. Make sure you really have pushed the Powerline all the way in. The resistance is very high (the jaws are as tight as regs allow to ensure the tightest clamping force) so it’s easy to only get the jaws touching rather than properly opened up and onto the pins.

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Turning off at low volume rather than high volume seems opposite to what you’d expect. If it’s dependent wholly on volume it would seem that the Powerline is inserted correctly. So it’s very likely the speaker leads or the unit itself. I’d borrow some NACA5 or SL from the dealer as first check. If it still does it then a fault in the amplifier seems probable.

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As James nsaid, I had the same kind of problem with my new Nap300DR.
The dealer took it back, and I had another one that works fine.
A bit disappointing for a high end material…


Thanks everyone for your suggestions and help. Appreciate it. I’ve just emailed my dealer to see if he will loan me another set of cables to try and then if that doesn’t work replace the 300DR.

Good luck Mark - i’ll be interested in what you find.


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