Possible fault with KEFs or NAIM

[SohoAudiophile]

Hi All,

I've been living happily with my first ever audiophile setup for about 8 months now.

Speakers: KEF R3 Metas & S3 Stands,
Streamer/dac/pre:NAIM NAC N-272 streamer/dac/pre
Power: NAIM NAP 200DR

A few weeks ago I started to realise that my left channel felt like it was audibly quieter than the right. In the NAIM's controller app you can switch the balance and I listened to both carefully and the left was definitely quieter.

In fact it's not just quieter, it seems like the right has much more bass extension and a fuller, higher quality sound. The left seems to have more mid and has that hollow 'gramophone' sound.

I tried the usual:
- Switching the speakers in the back of the amp (no change)
- Checking that I hadn’t put either speaker out of phase (I haven’t)
- Physically swapping the speakers to see if the culprit is room acoustics (It isn’t)
- Trying the alternative biwire terminals (no help)

I've also tried disconnecting the HF/LW bridge behind the speakers and listening to just the bass side-by-side, and just the HF. But in that case it became quite difficult to identify any problem at all.

I've contacted my dealer who has been very helpful but in order to get the speakers to them under warranty I have to wrap them up and post them 200 miles. I'm loathe to do this if there isn't a good reason.

I've tried testing using an iPad graphic equaliser app and there do seem to be consistent differences but the microphone on that is weak, I'm not sure how much low frequency it can detect and small differences in placement etc can affect the result.

I'm now starting to doubt myself and wonder if it's just me. Sometimes the difference seems obvious and ruins enjoyment of certain tracks Other times I move the speakers and I can't hear it any more. OR it could be one of the NAIMS and I'm just getting mixed up changing speaker cables and locations and all that.

Highly stressful! So I thought I'd check the brains on here!

Is there an objective test that you would do in this situation? What sounds or tracks should I play? Beyond relying on my own hearing is there any (affortable) equipment that I can absolutely depend on to test the performance of all the equipment here?

Thanks in advance for any help!

John

 

[podknocker]

Hi there.

If you've swapped the speakers over and swapped speakers and it's still quiet on the left channel, it does sound like the NAIM NAP 200DR left channel is at fault.

Have you swapped the outputs from the streamer to the NAIM NAP 200DR to see if it's the left streamer output or the left NAIM NAP 200DR output at fault?

If you swap left and right from the streamer to the power amp and the left is still quiet, then it's the power amp at fault.

If you swap channels to the power amp and the right channel is quiet, then your NAIM NAC N-272 streamer/dac/pre left channel is faulty.

Someone please correct me if I've got that wrong!

 

[daytona600]

Do you have/or can borrow another amp/speakers to check / compare

 

[nopiano]

I will try to decode your tests:-

- Switching the speakers in the back of the amp (no change)

So you connected L cables to R output and vice versa? No change means the left speaker is the issue. Either the speaker itself, or it’s placement or connection.

- Checking that I hadn’t put either speaker out of phase (I haven’t)

You can’t put *either* out of phase. If one is out then that’s what out of phase means! But it shows you’re connected ok.

- Physically swapping the speakers to see if the culprit is room acoustics (It isn’t)

What did you hear? No change? Need more info here.

- Trying the alternative biwire terminals (no help)

So, unchanged?


Ok, so you’re on the right lines, but you need to be more specific, and think it through logically. I think @podknocker is on the right lines.

My hunch is it’s either one speaker, the placement, or the power amp. Or you’re imagining it, because you listen to stereo which means each channel has different content. You need a nice predictable content, in mono if you can switch it, or central, like a BBC newsreader or continuity announcer. Or try white or pink noise (start with volume low) from YouTube or a streaming test source. You’re listening for changes in character or level between left and right.

Last thought. If cables allow, move speakers next to each other, as that reduces room influences. Obviously only for your experiments.

Get back to us, please.

 

[jjbomber]

Hi there.

Someone please correct me if I've got that wrong!

One other option is the left channel interconnect.

 

[twinkletoes]

Hi All,

I've been living happily with my first ever audiophile setup for about 8 months now.

Speakers: KEF R3 Metas & S3 Stands,
Streamer/dac/pre:NAIM NAC N-272 streamer/dac/pre
Power: NAIM NAP 200DR

A few weeks ago I started to realise that my left channel felt like it was audibly quieter than the right. In the NAIM's controller app you can switch the balance and I listened to both carefully and the left was definitely quieter.

In fact it's not just quieter, it seems like the right has much more bass extension and a fuller, higher quality sound. The left seems to have more mid and has that hollow 'gramophone' sound.

I tried the usual:
- Switching the speakers in the back of the amp (no change)
- Checking that I hadn’t put either speaker out of phase (I haven’t)
- Physically swapping the speakers to see if the culprit is room acoustics (It isn’t)
- Trying the alternative biwire terminals (no help)

I've also tried disconnecting the HF/LW bridge behind the speakers and listening to just the bass side-by-side, and just the HF. But in that case it became quite difficult to identify any problem at all.

I've contacted my dealer who has been very helpful but in order to get the speakers to them under warranty I have to wrap them up and post them 200 miles. I'm loathe to do this if there isn't a good reason.

I've tried testing using an iPad graphic equaliser app and there do seem to be consistent differences but the microphone on that is weak, I'm not sure how much low frequency it can detect and small differences in placement etc can affect the result.

I'm now starting to doubt myself and wonder if it's just me. Sometimes the difference seems obvious and ruins enjoyment of certain tracks Other times I move the speakers and I can't hear it any more. OR it could be one of the NAIMS and I'm just getting mixed up changing speaker cables and locations and all that.

Highly stressful! So I thought I'd check the brains on here!

Is there an objective test that you would do in this situation? What sounds or tracks should I play? Beyond relying on my own hearing is there any (affortable) equipment that I can absolutely depend on to test the performance of all the equipment here?

Thanks in advance for any help!

John

First port of call is swap the speakers around, left to right, it will tell you if there is a problem with the speakers or the pre/amps.

BUT this sounds like good old Naim unbalanced volume pot at lower listening levels, as the volume gets turned up the imbalance disappears, its inherent in there design (for better or worst). The problem will lay with the pre amp.

You could also check you connections are fully inserted RCA's/DIN's and loose speaker wire in the banana's

But what your writing sounds like classic naim volume imbalance.
If it bothers you unfortunately you'll have to box it up and send off for a "repair" which naim will do free of charge (if under warranty though the n272 is a fairly old device now ) and as long as its sent with the correct postage it will be fully covered. I'd send with parcel force personally.

 

[Al ears]

One other option is the left channel interconnect.

easy to swap L and R to check, agreed. However they usually work or they don't.

 

[Al ears]

As you suspect speakers best bet is to try to borrow another pair and see if issue is replicated.
Problems can occur when you biwire unnecessarily

 

[twinkletoes]

I got this with my Quad Vena 2 although turning up the volume sometimes didn't work. It was also scratchy and noisy. The ALPS pot was a sealed unit, so no chance of getting any electrical contact cleaner in there. Again, not a fan of volume knobs and pots. My Omnia has buttons for up and down and seems to be a better method. NAIM are really expensive and an issue like this is unacceptable in 'high end' audio.

Ive had few naim amps/pre's and they all have this problem, at a volume where its just bouncing off the min mark they can be really bad. Take it just over 8 o'clock and it will all level out, strangly I dont have this problem with my nait 50 so lucked out there!, but my superuniti had it my dac v1 had it (and other issues) and my 202 pre had it.

Some are worst than others, But agree it shouldn't happen at this price point, I will say it doesn't affect there new design uniti's with that funky control on the top of the chassis.

Google " naim volume imbalance " and its everywhere

 

[Al ears]

Ive had few naim amps/pre's and they all have this problem, at a volume where its just bouncing off the min mark they can be really bad. Take it just over 8 o'clock and it will all level out, strangly I dont have this problem with my nait 50 so lucked out there!, but my superuniti had it my dac v1 had it (and other issues) and my 202 pre had it.

Some are worst than others, But agree it shouldn't happen at this price point, I will say it doesn't affect there new design uniti's with that funky control on the top of the chassis.

Google " naim volume imbalance " and its everywhere

So are you saying his speakers do not have a problem?

 

[SohoAudiophile]

First port of call is swap the speakers around, left to right, it will tell you if there is a problem with the speakers or the pre/amps.

BUT this sounds like good old Naim unbalanced volume pot at lower listening levels, as the volume gets turned up the imbalance disappears, its inherent in there design (for better or worst). The problem will lay with the pre amp.

You could also check you connections are fully inserted RCA's/DIN's and loose speaker wire in the banana's

But what your writing sounds like classic naim volume imbalance.
If it bothers you unfortunately you'll have to box it up and send off for a "repair" which naim will do free of charge (if under warranty though the n272 is a fairly old device now ) and as long as its sent with the correct postage it will be fully covered. I'd send with parcel force personally.

This may be it actually - it might be at lower volumes.

Thanks to everybody for replying - I've got the weekend free so I'm going to go through everything and do checks as you've all proposed.

Appreciated - I'll be back with more info.

 

[twinkletoes]

So are you saying his speakers do not have a problem?

I don’t think so no not by what the OP is discribing . Naim have know imbalance issues that would be easy to diagnose by simply swapping the speakers around. If doesn’t follow the speaker I’d be looking the volume pot first

 

[Al ears]

I don’t think so no not by what the OP is discribing . Naim have know imbalance issues that would be easy to diagnose by simply swapping the speakers around. If doesn’t follow the speaker I’d be looking the volume pot first

I thought he had already swapped the speakers. His only option is to try borrowed speakers and, if necessary, borrowed amp.

 

[Gray]

This may be it actually - it might be at lower volumes.

Plug some headphones into the pre-amp.
If the volume control has any tracking error, headphones will highlight the issue.

Going slowly up from zero volume you may notice that one channel 'starts' before the other.
(Further up, there may still be a less noticeable imbalance).

That's the problem with analogue volume controls - there's no way that the resistance of the L and R tracks can be identical throughout the travel.
Fortunately, it's usually close enough not to be a problem for most people.

IF you confirm an audible tracking error......you can decide on your next action.

 

[RJW232]

BUT this sounds like good old Naim unbalanced volume pot at lower listening levels, as the volume gets turned up the imbalance disappears, its inherent in there design (for better or worst). The problem will lay with the pre amp.

You could also check you connections are fully inserted RCA's/DIN's and loose speaker wire in the banana's

But what your writing sounds like classic naim volume imbalance.

Interesting. Do you have more information about this issue? E.g. circuit diagram, information about the potentiometer used. Do they use the pot for gain control or to attenuate the signal?