Have an old NAP90, not the shoe box form factor it matches a NAIT3, and it’s developed a hum.
The hum isn’t volume related, disconnect the pre’ it still does it, and sounds like a mains hum, I think a pro’ repair would probably cost more than it’s worth and I’m not without music as I’m using the converted NAIT3 again as an integrated.
I have a pal who is an electrical engineer (not audio) who’s pretty handy with a soldering iron, what’s it likely to be? Is there one set of components that would be the culprit?
Or would you just put it on a well known auction site spares or repairs?
Thanks all.
Could be the pre amp at fault.
Connecting the pre amp usually stops the power amp humming.
If you want to keep it one place you could send it (if you are in the UK) to Class A Audio in Sheffield they are well used to dealing with Naim amps and are in fact a Naim-approved service agent.
First, it is worth disconnecting the amp and reconnecting it and possibly swapping the connecting SNAIC the other way round/checking it is orientated correctly.
If you connect it to the mains and remove all other connections does it still hum? If so likely to be the transformer mounting or the transformer itself.
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Checking the mounts is worth a check, after that, have a read here for other possibilities
Mmmmm.
I think we need clarification of whether the box is humming or is it humming through the speakers.
The hum is through the speakers but doesn’t alter with volume.
Try earthing the 90 to the nait 3 with a single strand of wire between the outside ring of the din connectors.
It looks like you have discounted hum from the body of the amplifier, so we are looking at electrical causes.
Disconnect the preamp and all other equipment. If possible, short the input terminals on one of your high level inputs (Russ Andrews Accessories used to sell plugs with shorted input terminals to eliminate noise from unused inputs). That should rule out stray noise coming in from input terminals.
Is the mains lead captive or removable? If removable, try replacing the mains lead. If fixed, check the mains plug for loose terminals.
Do you have two earths connected to the NAP90 (mains lead and earth terminal on the case)? Disconnect the terminal on the case.
In the past, I had an NAP160. Two friends of mine also had these and listened LOUD. The main reservoir capacitors on one failed and the amp blew up. The other friend asked me to look at his amp as I worked in a TV / audio repair workshop at the time. There was a puddle of liquid inside on the bottom of the case where the electrolyte from the reservoir capacitors had leaked out. New capacitors made the amp nearly as good as new.
A word of warning!! If you don’t know what you are doing inside mains operated equipment, just look and don’t touch (or better still, don’t open it up). Leave it to somebody who knows. Better skint than dead!
You may also have other capacitors that have started to leak, so worth checking them out.
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Yea could well be due a service
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