I have a nac72 hicap and nap140. My question is the following. If I switch only the nap140 power amp i get a fairly loud buzzing noise through the speakers. When I switch on the hicap which powers the 72 after about 10 seconds the buzzing disappears. If I switch on the sequence of nac72/hicap first wait 10 seconds then switch on nap140 then it sounds fine. When all 3 units are on there is no problem. Even turning up the volume with nothing playing there is no noise from the speakers.
For powering off if I switch off nap140 first, wait 10 seconds then power off hicap its fine, but if I switch off the hicap first the loud buzzing returns. Have I got a faulty nap140. All the units need servicing as they are over 25 years old but I need to wait till pandemic is under control. Any advice or suggestions?

That sounds normal to me.


The sequence should be for powering ON : HiCap/72 and then NAP140

OFF: NAP 140 then Hicap/72.

You are doing it wrong!! (some of the time)

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Completely normal, for this combo. Always switch on the HiCap first. Ideally, leave the HiCap on all the time…

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FAQ on this can be read here:

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Or just follow naims advice and leave them switched on permanently


I think you have answered your own question. And it aligns with the advice.
Don’t let covid stop you getting all three serviced. If you are not ready or able to fund all 3, then the question needs to be about which ones to do first. I.e. Best bang for the buck.
Others will provide the proper answer, but I’d expect the priority to be…
Hicap,140,72. Based on the capacitors being the main degrading items.


Agreed same order here. All serviced.

Thank you for all the replies. I found one of the speaker cables was loose at the back of the nap140. Pushed it in and all is fine now. I know the startup and shutdown sequence for the units. It was only mentioned as I was testing if I had a fault with the 140 which is not the case. All fine now thanks to everyone


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