Good morning! The purpose of this post is to ask for help in narrowing down the cause of a potential fault in my Naim system so that component can be sent to @NeilS to be fixed. Some back ground:
System
Naim 52 and Supercap, Superline, SNAXO 362, Hicap, 3 x Olive 250, DBLs. Sources SME 20/2a and Linn KDSM2.
Cables:
Standard Naim SNAICs, NACA5. Only ‘non standard’ is line level from KDSM to 52 which uses Naim Aro cable made up by myself with WBT phonos and Preh DIN.
Service status:
All components have been serviced by Naim or Class A within the last 2 years.
Issue:
I have an intermittent ‘interference-like’ sound audible through the loudspeakers. This has not occurred when the system is cold, only after a few days or warm-up or use. This interference is at a low level and through both speakers and all drive units. It resembles a ‘tap’ ‘tap’ like noise, almost as if I am picking up wifi interference or signalling from my mobile phone or a poor connection. However, I would expect that to have structure, this does not. It appears to have no structure. There are no accompanying hums or buzzes either, suggesting cabling is good.
Sleuthing to date:
I have noticed that:
The ‘interference’ only appears after a few days of the system being on. I.e. not from cold.
I switched off my phone, and the wifi with no positive impact. No new electronics have been recently introduced to the house.
Muting the 52 has no impact. The ‘interference’ persists through this unchanged.
Changing the selected input on the 52 has no impact. The ‘interference’ persists through this unchanged.
Altering the volume on 52 has no impact. The ‘interference’ persists through this unchanged.
It seems that when the ‘interference’ is occurring, muting the 52 produces an unusually sharp ‘click’ through the speakers when the mute is activated or deactivated.
I have unplugged and replugged the cables to clean the connectors, but no benefit.
My conclusion
I initially concluded that the issue appears to be from the NAC 52 and likely something in its output stage (independence of volume, input etc etc). But….perhaps coincidentally, if this ‘interference’ occurs, then it seems that switching off and the NAP250s and then back on seems to clear it. Odd. This suggests the SNAXO 362 as a potential root-cause.
Any ideas or previous experience to narrow things down before dropping equipment off a the dealers and Naim?
If muting the 52 makes no difference then it is the SNAXO or power amp or its power supply. First thought os mains-borne interference, but: Does it start consistently the same period of time after turn on? Does it ever start a lot earlier? And do gaps between interference when remaining on ever last as long as the gap between switch on and it starting?
Is it all channels - L, R, Bass, mid and treble? If so then almost certainly mains related. If not then that starts to narrow down.
Have you tried turning on one piece at a time,
Start with the amps one at a time if no noise,
Turn on snaxo power if no noise turn on the 52,
Just a thought it’s something I would try
@Innocent_Bystander Thank you. Power amps are likely innocent unless all three are broken! Periodicity appears random. Bass, Mid, Treble all impacted. It’s odd. Quiet as a mouse this afternoon. Chirruping away this morning.
@GrumpyOLDvinylJUNKY Unfortunately, active systems have a particular switch on order (unless you like fairly hair-raising clunk noises) hence this is difficult to verify.
@NeilS. Thank you, especially for replying on your day off. The Supercap is the good old fashioned LM317 type. I will try you suggestion. The Superline was one of the last to be serviced and the start of the noises do seem to coincide with this. That and I’m looking for an excuse to buy one of those NOS Supercap DRs I see on dealer’s sites… I will try your suggestion and perhaps use this excuse for some retail therapy…
Have you (first) disconnected the 52/SC from the system, (second) disconnected the SNAXO from the amps? This should identify the location of the issue (52/SC, SNAXO, 250s). Unlikely but not impossible to be one of the 250s.
Righto. Latest results. Switched on power amps to immediately hear the odd noises coming through the speakers. Then:
Powered down power amps and 52/Scap and then disconnected Superline. No impact. Same noise.
Powered down power amps and 52/Scap and then powered back-up with Superline connected. Same noises.
Power down power amps and SNAXO/Hicap. Powered up one power amp - the bass one as I can get those drivers fixed if it all goes wrong. Noise gone except for normal low level hum as no signal to power amps.
Hence it would seem the issues sits in the SNAXO or Hicap. @NeilS (sorry to bother once again). In your experience (and without prejudice or commitment) is one more likely than the other to cause an issue? I’m trying to avoid a NFF situation! Thank you all!
Could you try connecting the bass 250 directly to the Supercap? (Remove the other connection to the Hicap)
So 52 to Supercap to bass 250. If that’s ok, then connect the sources to the 52 & check again.
Thank you, and thanks once more for replying outside work hours. I appreciate it. All wired up as per your suggestion. For now, I have left the Superline connected. Let’s see how it goes. So far all is normal….other than the the sound of a full range signal going through a 15” bass unit. .The sound quality reminds of some other speakers I have heard over the years!
Okey doke. I left the SNAXO/Hicap out the system for a couple of days and experienced no issues. Interesting.
In the meantime I bought a new HiCap DR (always handy and because I could….).
New HiCap is now wired to SNAXO and the system is up and running. Let’s see how that goes. However, I have already noticed better sound and the 52’s muting behaviour is rather better - no clicks.
BTW a full range signal into the bass driver reminds me very much of sound from Linn Saras……