Possible hardware Issue

Hi all looking for some advice.

My Atom and ProAc Tab 10 Sigs have always worked well together for just over 2 years. However recently I have noticed a a big increase in HF response which has had me moving speakers about, changing cables, powering down fully and reseting the Atom to try and aleviate it. None of this seems to have helped for any length of time, I do think I can hear some distortion at this high end to its ridicualously bright. Its became unlistenable now for certain recordings which it never was before

I often use DSP in Roon which has been inactive during this , so I did some fresh readings and noticed that these did seem to be elvated from about 4k. Having sent them to Thierry at Home Audio Fidelity I asked him to compare against previous readings and he could also see the same increase in HF energy. He doesnt seem to think this increase could come from just the environment hes looling into them more for me but he hinted it might possibly be the speakers or amp causing it. I have moved the speakers around but cant seem to reduce it at all.

Any ideas as to if this could be a fault with the speakers or the Atom? I might have to have a trip to the dealer which is the same for both luckliy. But not ideal.

Without being rude, are you sure it’s your system and not your ears?
May be worth getting a hearing test. Our ears’ response to frequencies change as we age.

Did you read my post at all? This bump is showing up in the readings of the output and what I am detecting matches the frequency response captured and this has been verified by a 3rd party that it’s changed. Yes I am more sensitive to hf these days but this wasn’t present before in my room and now is.

All other systems are fine no such issues.

My first approach would be to compare your Atom with your dealers demo. Doing this in your own room and system might make the differences easier to discern, but for a straight comparison, using their demo room should still show up any differences.

It might also be interesting to compare older firmware versions, although you would have to talk to Naim support and persuade them to arrange it for you.

Not sure if changes at Roon could be contributing to this, but obviously you can use Naim native UPnP or other sources to compare. Still my gut feeling is that maybe the deterioration of a component in the Atom could be the more likely culprit.

Thanks Chris. I tried UPnP same issues are there it’s not the source. I did plug the speakers earlier into my Arcam Av as that feeds atom for Av duties. It definitely sounded flatter but other variables there such as the streaming source. I didn’t take a reading which I should have done.

Will look to update firmware and do a factory reset again as I got a notification of a new one the other day. See if helps.

Have you looked at each channel separately, and is there data from previously with which to compare? If a similar change on both channels happened at the same time I can’t see any way that it could be the speakers (as opposed to if the treble had gone due to both tweeters damaged by an electrical ‘spike). The only thing common to both channels in the amp stage would be the PS, unless the Atom is a dual mono design, which I suspect not? Anyway it is hard to see how anything there could have the noted effect.

That leaves the digital end. One thing reportedly known to cause false ‘brightness’ through interaction in some DACs is RF modulation, which can be via ground plane, or superimposed on the digital signal. Have you made any network changes (including non-hifi related things connected to the network? Any changes in connections to earth (ground) of either Atom or anything connected to it? If no changes at all, other possibilities include something significantly changing the RF levels in your home (which could be in the external), or getting in through the mains electricity supply. How likely any of these are as the cause I don’t know, but I offer as thoughts for consdieration.)

Just a thought could it be a problem with the speaker crossovers

No nothings changed, i even unplugged everything on the same circuit no change.

I am away now until Monday so can’t really look at anything else.

Well not sure what managed to tame the excessive brightness but upgrading to latest firmware, full factory reset, and I noticed ground switch was not in default ( don’t remember moving this) it sounds a lot better, thank god. Crisis averted for now. Who knows it might return it was powered completely off for 6 days.

I heard that ghosts like to touch the ground switches during the night. Time to call Men in black. :laughing:

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Well it just returned to sounding bright and brash and artwork stopped showing on the display. I think I have worked out this happens after I have been using the analogue in which is set to AV fixed volume. I full power down has restored it, also noticing that after unit comes up it’s taking ages for the display to show the usual menu, stays on the Naim logo for ages, used to be much quicker.

Is it on guarantee still?
The ground switch is still in the right position?

Nothings changed, no it’s out of warranty.

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Sorry for you. A trip to Salisbury seems to be necessary, not?

No I am not driving to Salisbury back to my dealer I will go. May just change to something else I am not sold to Naim at all plenty of other excellent gear out there, perhaps that is less troublesome.

I mean a trip of the atom, not you with it.

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