NAT02 Low-Pass filter issue

The frequency sweep of my NAT-01 shows pretty good rejection of the 19kHz pilot wave (around 50dB rejection) . I don't have much beyond 21kHz as this was archived to a CD-R which cuts off steeply at 22k. Your sweep shows the ultrasonic noise to be pretty low level in amplitude. And of course any respectable Naim preamp would further attenuate these ultrasonic aberrations. 

How does your NAT02 sound though?

Hi Ron thanks for your post.

To answer to your question, not so good. In fact, I have tried to low-pass the recording @ about 21kHz and strangely, even on ultrasonic frequency, it improve sound a lot.

The graph for your NAT01 looks pretty normal, even considering comparaison on different tuner, recorder, software and kind of graph ( I choose linear frequnecy to highlight the problem).

I have just compared with other tuner I have at hand, and it definively shows something is wrong. For exemple bellow is an old Pioneer TX-9500II that look more "normal"

I will try to locate the wright people to have look (throug naim uk, or focal in france).

Hi Olivert, it does indeed sound like your demultiplexer has gone into some bypass mode and you are hearing the stereo (L-R) AM multiplex which from memory has sidebands either side of its 38kHz carrier .. I am afraid it's back to Naim it needs to go.

S

Hello again

Just check with my helpful local retailler. The distribution have been taken back in France by Focal the parent company. In the change, prices for repair have been largely increased. They charge 540 euros for a repair (it's flat rate). It does not make sense related to the cost of the unit !

Will try to find an alternate solution.

But in my mind it shows the factory is not interrested in the long term maintenance of their product. Making them far less appealing...

Can you buy another Nat02 for €540? And even if you can, would you want to?

C.

You could always try contacting Class A in Sheffield, where it is likely to be cheaper, though there would be postage to consider too. 

AFAIK the Naim factory are the only ones who have the necessary equipment and skilled technicians to service and align the tuners.

If the tuner head needs re-alignment too, it's probably back to Naim since they have the equipment. It all depends on how much listening you do. I had my NAT 01 fully serviced by Naim (including the NAPST) for 450GBP 5 years ago and it's in almost daily use. Not bad value for money but obviously not so good if it sits on a shelf switched off for most of the time.

Another thing to remember if that some parts such as the displays and tuning heads are no longer made....but that didn't put me off.

Radio quality on a decent BBCR3 live broadcast gives my NDS streaming hi-definition radio a real run for its money.....not bad for something dating back to the early 90s.

Ravenswood10 posted:

Radio quality on a decent BBCR3 live broadcast gives my NDS streaming hi-definition radio a real run for its money.....not bad for something dating back to the early 90s.

1890s for Marconi's experiments with wireless telegraphy on the Isle of Wight, but oh, sorry, you meant the NAT radio itself

C.

Thanks all for you comments.
To answer Christopher, the second hand price for a NAT02 in France is about 500 euros. So could I by another one ? yes. Will I ? probably not. The recommandation from my local Naim dealer : change all the capacitors by myself and have a look ! At worse, I still can have it fixed for the same price as it is fix rate.