300DR symptom query

I experienced something with my 300DR today that I’ve not seen before and wondered if any of the cognoscenti on here had any views or advice on it?………

I’ve had my system shut down this week for 4 days to avoid potential lightning strikes. Happily there were no mishaps.

When I powered everything back on today (in the right order​:+1:) all was well for about 10 minutes……then……without any warning the 300DR powered down. :slightly_frowning_face:

I switched everything off again, left it for 10 minutes, then powered up again = still no 300. I left the room for 5 minutes, came back in and it’s back up and running. All is well now. Weird.

Anyone seen this before? Ideas?

I think there is a loose connection between the PS and the head unit.

1 Like

Thank you - I’ll check and tighten everything up.

Is the power button engaging properly? IIRC, there have been instances where the button doesn’t 100% engage when pressed-in and can relax out/off.

I think it’s been said it’s wise to disconnect (at the plug) and press the button a few times, to re-awaken the spring.


Thank you

That’s a bit strange, especially as it came back to life again after a few mins of being switched back on. It almost sounds like the thermal cut out switch in the 300PS was triggered. Hopefully just a one off.

I’m sure I remember @NeilS posting about a similar issue on another 300 a while back so perhaps if he is around, he may be able to comment.

1 Like

Spot on James - something erroneously triggered the thermal trip on power up.
As the mains supply is in a separate box (the 300PS), thermal monitors in the head unit trigger a voltage across a high power resistor in the PS. This is strapped to a further thermal trip in order to interrupt the mains power in the event of a major over temp situation. It takes a little while for the resistor to reach the temp required to fire the mains trip & equally to cool down again & restore power.



I turn my system off at the end of days I listen to the system, which means I turn it all back on again when I want to listen another day. I have never had such an issue, although I did have my 252 output mute relay fail so that one channel didn’t work. Naim fixed that at no cost.


I and, I suspect, most users follow Naim’s advice to keep the system powered up at all times except when (for example) there is danger of a lightning strike or similar. (You are also advised to unplug everything from the mains when lightning is around.)

As a result, my system is left powered on almost all the time. (I don’t suppose that this does my ‘green’ credentials any good.

I used to keep my system powered 24/7/365. Now that I power off every night I just try to remember to power on 30-60 mins before I plan to play music. Keeping the system powered off when I don’t use it has not diminished enjoyment of the system in any way that I can tell.

You’ll save a little bit on electricity, but daily switching the equipment off and on will result in electronic components failing much earlier.

Your money, your choice.

1 Like

Really? Naim says this? Where? I’d like to see that. Or is this just conventional “wisdom” without any real teeth?

Edit: I looked at my manual and it says “better and more consistent performance will be achieved if the system is left switched on for long periods” but it says nothing about your claim of premature failure of components if they are switched off.

1 Like

Thank you for all the helpful replies. All is well and I haven’t had any further outages. Before I powered down last week my system had been switched on for pretty much 2 years so I’m confident that will now be repeated going forward :+1:

Incandescent lightbulbs maybe (see Livermore Centennial Light Bulb) but I’ve seen more equipment fail due to being left on. E.g. Denon dbt3313 is notorious for PS going pop just by being left in standby. Luckily I fixed mine. I do leave my Naim stuff on though.

I turn them off nowadays. If keeping the equipment on 24/7, capacitors will be aged too fast. What is the lifespan of the capacitors? Around 13000 hours? The equipment will still work but the SQ will significantly decrease after 2-3 years.

I think the 13.000 hours specification is with a temperature of 85 or 105 degrees Celsius. Lifespan also is dependent whether you play a lot with the volume at 12 o’clock or mostly at about 8 or 9.

13.000 hours/ 24 days is about a year and a half when left on 24 h/day. That would be very quick for a recap :grimacing:

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.