Naim nap140

Recently my power amp NAP140 upon power up gives
continous humming sound through the speakers till I switch off power. I disconnect all the sources as well as preamp NAC32.5 but the same problem persists. I tried on the other power socket but same problem. As last resort, I disconnected my fridge and washing machine but same problem. My engineer says it might be grounding problem. But I am using the same setup for last 30 years without any problem.
What could be the problem? Any suggestion. No Naim authorised service centre in Bombay.
Also changing the capacitors in my 25 years old naim power amp, will it improve the sound quality?

If you haven’t serviced the NAP140 in 25 years, it is absolutely time to do so, regardless of any other factors.

Our own experience of Naim power supplies (555PS, XPS2, Hicap, Supercap, NAP135, NAP250 and NAP140) indicates about 7 years for regulated amplifiers and up to 10 for the other items. So our NAP140 is due another service in 2 years time. Naim’s Service Dept advised us not to leave even pre-amps longer than the 16 years we had left our NAC32.5.

Best regards, BF

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The famous Hum that Naim Amps and power supplies can give is usually just heard at the power amp, and not through the speakers. It does sound like a service would help.

I had the same problem some years ago. It was a broken cable between Preamp and Hicap. Could also be a ground loop: If a tuner or streamer is connected try to disconnect the aerial/cable and the Ethernet cable.


Just a thought.

A nap/nac will produce a humming sound until a reed switch (???) in the nac is engaged. The switch doesn’t switch if the voltage isn’t high enough.

Check the voltage powering the Nac.

The original post says the hum is through the speakers, so a service does sound like the way to go.

I did send my NAP140 for service to my audio engineer for getting hum upon power up.
He said that there is no hum when he connected my poweramp to some instrument. Also he connected my pre poweramp to his audio research system and there is no humming from his speakers.
What could be the problem? Very difficult to detect the problem?

What’s the rest of the system ? Did you add or change anything when the hum started. Can you still hear music above the hum ?

Is it definitely a hum, rather than white noise? Can you record it on your phone? Also try an extension lead from a different ring mains, eg upstairs

Could be a faulty SNAIC. Have you done a simple continuity check on all connected pins?

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I am staying in Bombay and supposed to be authorised dealer says we have authorised service centre in Bombay, but he refused to give us the contact number or the address.
Can anyone or Naim audio confirm that they have authorised dealer as well as authorised service centre before I buy new Naim amp?

As is the case in the UK, I suspect that all equipment must be sent via a dealer, not directly to a service centre. If this is the case, they will not share the details, in order to avoid everyone trying to send equipment directly.
The dealer will ensure the item is correctly packaged to avoid damage and can control all elements of returns for repairs.
However, I do not know if there is actually a Naim Service Centre in India, or if the dealer simply returns items to the UK headquarters.
The dealer for Mumbai appears to be:
A K International

A’ Wing Poonam Chambers

Opp Atria Mall, Near Ceejay House, WorLi

Mumbai Maharashtra 400018


022-43444786, +91 9004007863

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