Significant "unsolicited" volume level increase causes?

Hi there suddenly I just noted that the volume levels have increased by « 2 hours » : when I was usually listening at around « 8 o’clock », now it is « 5.30 or 6 o’clock » which really I believe is not normal … I’m so surprised and wondering what can have caused this? In fact I’m a bit worried this may be due to some disfunction…but the SQ and enjoyment are the same.

I am experiencing this streaming through the ND555. I have not “just” changed anything.

Not complaining but wondering if this could be a “symptom” of needed maintenance/revision…

Nestor, you’re saying that what was originally a decent volume level at 8 o’clock, now needs the volume dial wound round to 5.30 or 6 o’clock! that’s not at all normal and I’m surprised you haven’t hit the end stop of the volume pot by that time. Is your volume knob slipping or loose? I would switch off and check it’s travel.

Other than that, is it just for the ND555 source?

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Has your streaming service settings changed, possibly after an update? I know Tidal has some volume equalising function that may cause an unwanted level boost. I have it switched off but I’m sure I’ve had to go in and do this again as it turned back on without being asked!

Quite, that’s where my question was leading re. whether it’s just limited to the ND555. If it’s an issue affecting all sources though…

I think he’s saying wind the volume back to 5.30 or 6 from the normal 8…



On my NAC552, which should in all essence be identical to the Nestor’s 552, 5 o’clock is max volume and 7 o’clock in minimum. If the volume knob is pointing at 5.30 or 6 o’clock, something would appear to be very wrong with the vol knob positioning.

Maybe there is the answer - the knob is slipping on the shaft…??!

This probably isn’t the time for a knob joke, tempting as it is.

Exactly my first question above…

Ah yes! I don’t have a 552…

Try to connect your nd555 directly to your router, and see if it’s ER/ lps effect or not.

Hi Richard, many thanks for the very sensible remark…I should have asked myself the same question as indeed I felt strange that I could go so far in the “minimum”…I will check when I’m back home if there is a mechanical issue: makes a lot of sense. This shows the high esteem I have for my naim gear, I could not even imagine the possibility of this occurring!
Regarding sources I cannot say because as of now it is the only one (I would need to get the old cdp out from the box).

Thanks! I do not think so. I’m using Qobuz exclusively

I will check when back home, but clearly the mechanical point is the main suspect. How could this happen I do not know. I think I will have to “pull” the knob…and see if it is loose.

Bingo, when I turn the volume knob on the nac552 anti - clockwise, actually it slides further, it is not blocked on « zero volume » as one expects…so I corrected it now by doing a full circle.
But is it normal? Is there something to be replaced?

@NeilS should hopefully be able to explain how you can tighten it yourself.

Viz readers look away now…

IIRC there’s a nut that tightens over the hollow shaft of the knob to secure it onto the pot shaft. If the nut loosens, so does the grip of the knob on the shaft.

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No but get your dealer in to fix it, if he’s up to it. The other pre amps have splined shafts and plastic knobs (steady now HH), the 552 has a large lock nut securing the knob in position on a smooth shaft, it took the largest spanner I have (32mm) to fit it. I only half remember but opening the case required the transit screws so it can be inverted to remove the feet and possibly another screw or two, then, the right way up again, they have to be removed so the sleeve can be slid back while keeping it level, a feat Simon achieved with the amp balanced on his knees. There might even be a torque value for the case screws too when they go back in.

This is known as a collet type knob. There is no need to take the equipment case off to tighten this. Normally you can prise off the plastic end of the knob to access the nut and holding the knob with one hand tighten the nut with the other. The torque isn’t important - it has to be tight enough not to slip and not so tight that anything cracks.

You should use a socket to tighten the nut, but needle nose pliers may work too, if you are careful.



The nut and shaft are well within the case, so I think the cover has to be removed to tighten this. @NeilS can probably advise further.