Serviced NAP 500 non DR Channel imbalance?

Hi-Fi Corner
1

Hi,

some of you may remember my last posts about the service to my NAP500 and how glad I was about it.

Well, after 4 months I have a suspicion or more like a feeling that my left channel is a bit lower than the right one. It is a feeling I cannot pinpoint it because my room may well interfere with it.

Qualitative methods of listening from various points in the room or try to identify a possible interference are not working.

I need a quantitative method to put a final word on this issue. Ideally, I need some sort of device that can measure the output at each end of the speaker to measure the actual signal strength using, say, a wave signal.

I am not sure I can use a voltmeter or an oscilloscope, so maybe someone can help on this?

Thanks a lot

Salvo

2

What Preamp do you use ?

3

Hi Salvo,

I am not a current owner of any Naim amplification of the grade you have.

I have searched the forum and found the thread and pictures you posted of LASA doing the service work in Italy.

There are some simple things one could try to confirm by measurement channel balance differences.
However, before I start to go very very technical, have you asked LASA what to do in your home to diagnose and confirm your perception?

E of E

4

NAC 552 but is not it.

5

No Edmond, I have not. As I’ve said is a perception, but an insistent one, but before I start alarming people I want to self diagnose the issue if I can.

1 Like
6

Does swapping the L and R speaker leads at the rear of the 500 cause the perceived imbalance to also swap ?

7

No, I tried that. This is why I think it may be me. But as I said, I need a quantitative way of testing it.

8

I see ,often the 552’s have channel imbalance.

9

Igel, It cannot be because I have and headphone amp attached to a pre/out port, and listening with my headphone I cannot detect any imbalance. It is only when listening in the room with speakers and the NAP that the issue is perceived.

10

I see ,have you changed the speakers

left to right ?

11

Volume dependent? My old 552 did that at low volumes. At super low volumes one channel disappeared before the other. A bit of a “they all do that sir” when I asked questions about it. S1 doesn’t do it :grinning_face:

3 Likes
12

Well Dan360,

that takes the sting off this issue a bit. Glad you shared. Envy your S1! My wife would love it as a pretext to kick me out of the house :rofl:

Anyway, would still like to test for real channel comparison.

13

It’s probably just the room if the issue remains on the same side once the speaker cables have been swapped over. Try using some damping material in various places around the room to see if you detect a difference (just to satisfy your curiosity!).

14

The ideal would be to attach, at the end of the speakers cables, a two channel oscilloscope (which I have) rather than the speakers and feed a 1Khz, 2, 5, 8, 10… kHz signal through a source and see the wave output at various volumes is.

The point is: can this damage the amp? Not having a load at the end of it, what would be the result. This is really the issue.

15

Easier to to swap the speaker cables left right and just listen .

16

Done that Igel, as said the room could be playing up on this, but cannot tell.

1 Like
17

Okay and no difference when swapping over the speaker cables ?

Switch over the speakers if possible.

18

done that too

1 Like
19

Is your headphone amp attached to a pre out on the 552PS? Assuming your headphone amp has a volume control you would usually connect it to one of the DIN inputs (I think 4, 5 or 6) which have a fixed volume output.

2 Likes
20

Seems to be the room then..

1 Like