I appreciate that, thanks! I know that DR relates to the power supply as opposed to the output stage. I’m using it as an easy designation of age as opposed to the older amps. Amps wise stuff has changed quite a bit since prior to 2012. I know that older Naim amps didn’t have Zobel networks and therefore all the manuals had warnings about using specific Naim cables of at least a specified length, whereas the new owners manuals don’t make the statement about length anymore.
But they do specify cable length.
1.2 Loudspeaker CablesLoudspeaker cables are vitally important. They should each be at least 3.5 metres long and of equal length. The recommended maximum is normally 20 metres although longer cables may be viable with some Naim amplifiers.
Only in the older manuals. I have read the same in the older ‘Amplifier Reference Manual’ that covers everything back to the original Supernait.
But go have a look specifically at the ‘Power Amplifier Reference Manual’ at the notes for the specific model rather than the generic cover notes. ( https://www.naimaudio.com/sites/default/files/products/downloads/files/Power%20Amplifiers%20Reference%20English%20Issue%202B.pdf )
My quote is from the manual on the Naim website…
As indeed is my link.
It’s as plain as day!
It is. I’ve read it. Then on some of the amps in the specific pages it starts to say things like thus under 'Speaker Outputs : set of stereo speaker connection sockets is provided on the rear panel. Custom Naim loudspeaker connectors are supplied to make the connection and in order to comply with current European safety regulations these should always be used. Naim speaker cable will provide the best results, however, a wide range of speaker cable types can be used without risk of damage to the amplifier.
Ensure when connecting speakers that they are “in phase”. That is, the positive and negative connection orientation at both the speaker and amplifier ends of the cable is the same for both channels."
And only that. Thats my point. Each amp has different cover notes - thats all.
It’s only the integrated amps that are speaker cable flexible.
I would not run a speaker cable less than 3 meters from your nap 300 dr. No respectable Naim dealer should advise that.
@Richard.Dane should confirm.
I’ve never run anything less than 5 meters.
I should have confused something…
I’ve confused the discussion about my comments above. Every amp manufacturer would have concerns about too short speaker cables. I’m not disputing that. I was just saying that with the fact that Naim amps now include Zobel networks, cable specs seem to have been relaxed in comments that I’ve contrasted in various Naim amp manuals.
1 Like
From the manual you link to, I quote;
Loudspeaker cables are vitally important. They should each be at least 3.5 metres long and of equal length. The recommended maximum is normally 20 metres although longer cables may be viable with some Naim amplifiers.
Some Naim amplifiers are designed only to work with Naim loudspeaker cable and using alternatives may degrade the performance or even damage the amplifier.
The classic amps are a bit more robust than of old, but they still need a particular inductance for stability and can be upset by some non-Naim speaker cables (see the second paragraph with the warning quoted above).
Back up and running. New 300DR and 300PSU installed. Also changed across to NACA5.
Had it running for 4 hours so far. No powering down issues 
glad the 252 is behaving itself and wasn’t the culprit.
2 Likes
I don’t think this is true. I use 2.5m lengths of Tellurium Ultra Black II speaker cables with my 300DR (& previously with my 250DR) with absolutely no issues. For peace of mind, I contacted Naim support whether there’s a risk of longer-term damage to my amp, and they confirmed that they couldn’t forsee any issues with my cables.
For what it’s worth, sound quality is by no means compromised In fact, the TQ cable outperformed equivalent 3m lengths of SL cables considerably.
3 Likes
Good news. Did the dealer say what the issue was with the old 300 ?
2 Likes
The thinking is a faulty thermal cut off. But that will be up to Naim to finally figure out. The new one is working flawlessly. Been running 8 hours now. Low volume, Listening Volume etc and no issues so far…
1 Like
Good point that it works perfectly. I just repeat what I have often read. @Richard.Dane pointed recently the contrary too …but if it works, it works.
Yes that does sound very likely given the symptoms. Glad the new one is working well. Enjoy 
1 Like
Just a possible little follow up on this topic:
We received a 300/PS combo at Naim HQ exibiting this fault, which I am assuming are @Athos’s original units.
At first they were not tripping out at all, I left them playing quietly over a weekend & by Monday morning the 300PS was in a permanent trip cycle.
I traced the fault to a high resistance short circuit on a transistor within the 300PS trip circuit. Probable cause was solder “tin whiskers” being masked by flux.
I’m keeping an eye out for @marka’s units - if it turns out to be the same (or similar) fault, I will be raising it as a care point with our Quality Dept.
Apologies to both affected parties & I’m pleased you now have happy 300s!
Regards
Neil.
4 Likes
Hi Neil,
Thanks for the follow-up on this! I really appreciate it. I’ve had my replacement units on now for 30 hours straight with both listening volumes and lower volumes during the day and over night. Its been playing faultlessly. When paired with the 252 the 300 is a joy!
I also just bought a Naim mu-so QB 2nd Gen for my office. Loving this too! Thanks again!
2 Likes
My new 300DR is imminent (head unit arrived yesterday, PS is due today). Here’s to getting a faultless one.
1 Like