I have had my Nait 5i integrated amplfier for 3 years. I noticed recently that if I turn the volume up, while selecting an input that has nothing hooked up, or an input with the source not playing music, I get hum in the speakers.
Now the hum is not always there. From the 7 o'clock position (volume off) to about the 11 o'clock position on the volume dial, there is no hum from the speakers. It is dead silent. Starting at 11 o'clock, the hum is present, and gets louder as I increase the volume by turning the volume dial.
I never noticed before, because when I listen to music, I usually listen between 9 and 10 o'clock. Rarely, I will go up to 11 o'clock for a few minutes. I get plenty of volume between 9 and 10 o'clock. The sound is great. I never would have thought the amplifier could have a problem (if it is a problem).
I know this is not a ground loop; because those are present at all volumes and does not increase with the volume. Is this humming normal? Is it simply because the volume is set too loud starting at 11 o'clock? Maybe the inputs are picking up RFI or EMI and amplifying it?
I use 5 meters of Naca5 speaker wire with Sonus Faber Venere 2.0 speakers. None of the interconnects touch power cables, and all components are plugged into the same outlet.
Any help or explanation would be appreciated.
Posted on: 27 September 2016 by Huge
It's breakthrough into the contact(s) of a DIN or phono socket without a plug inserted to shield the contacts. It's normal for it to sometimes occur under these conditions.
What's not normal is to listen to an unused input (normally you only listen to used inputs that have shielded cables inserted and a source component connected at the other end - if it doesn't hum on those inputs, then everything's OK).
Posted on: 27 September 2016 by Adam Zielinski
Daniel - under some conditions you will notice a speaker hum, even on mute. Loads of threads on this topic - one of Naim's quirks (the other one being humming transformers).
Having said that - with a good mains and a well set up system, the humming is practically non-existent.
Posted on: 27 September 2016 by Daniel H.
I went to my dealer today to test a floor model 5si. It does the same thing, but to a much smaller level. The store model starts humming very slightly at 11 o'clock (after careful study, mine starts at 10). The store model hummed more when the volume was set to 100%, but not half as bad as mine. I tried mine at full volume and the hum was very loud. I've started hearing the hum in soft passages listening to music when the volume is at 10 o'clock. It did not do this before and it bothers me!
I wonder if there are some worn out capacitors? The volume dial is also somewhat noisy when using the remote. I also noticed the store model's volume dial stopped "solidly" when turning the dial to zero, like hitting a wall. Mine is soft and spongey as if there is no clear limit for the zero setting. Maybe a faulty volume pot?
I've had it for 3 years, but it was a B stock when I bought it. Maybe it had a lot of mileage and had been pushed hard during some trade shows. It came with the full warranty, so I am covered. I will have to bring it in for servicing.
Posted on: 27 September 2016 by Daniel H.
I went to my dealer today to test a floor model 5si. It does the same thing, but to a much smaller level. The store model starts humming very slightly at 11 o'clock (after careful study, mine starts at 10). The store model hummed more when the volume was set to 100%, but not half as bad as mine. I tried mine at full volume and the hum was very loud. I've started hearing the hum in soft passages listening to music when the volume is at 10 o'clock. It did not do this before and it bothers me!
I wonder if there are some worn out capacitors? The volume dial is also somewhat noisy when using the remote. I also noticed the store model's volume dial stopped "solidly" when turning the dial to zero, like hitting a wall. Mine is soft and spongey as if there is no clear limit for the zero setting. Maybe a faulty volume pot?
I've had it for 3 years, but it was a B stock when I bought it. Maybe it had a lot of mileage and had been pushed hard during some trade shows. It came with the full warranty, so I am covered. I will have to bring it in for servicing.
Posted on: 28 September 2016 by Huge
Daniel,
If the hum is getting worse, then that does suggest a possible problem - yes get it checked under the warranty.
N.B. just don't assume that this is capacitors, it could be lots of things. Incidentally capacitors don't usually actually wear out, it's more like suffering from old age, and that usually takes 10-15 years before it becomes significant.
The sponginess at the end of the volume control's movement is unlikely to be the pot itself, much more likely that the fastening arrangement holding the knob to the shaft is a just little bit loose! (Oh yes!, and don't twist it too far or you can damage the leads that connect to the LED.)
Posted on: 28 September 2016 by hungryhalibut
Well, it sounds odd to me. In 33 years of Naim ownership I've never had any hum during quiet passages. If it is breakthrough from unused inputs, I'm sure I've seen little blank plug things that you can insert into the inputs - I'm sure your dealer can advise here. A check under warranty sounds like the best idea.
Posted on: 28 September 2016 by Daniel H.
Problem solved! And, it had nothing to do with the Nait 5i. I wanted to eliminate all possible sources for the problem before going through the hassle of bringing the 5i in for servicing. I put the volume loud enough to hear the hum (with no music playing) and proceeded to unplug every other component in my power distributor and power bar one by one.
By the third component, I found the culprit. I have a device that filters the USB 5V and reclocks the signal from the Mac Mini (used as a music server) before sending it to the DAC. I plugged and unplugged it several times and the hum came and went along with it. I took it out of my system and plugged the USB cable from the Mac Mini directly to the DAC. NO HUM whatsoever.
I will get the device repaired under warranty and sell it. Too much hassle for the benefits it provided.
