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Naim dac hissing

A

asmith17

pfm Member
Looking for some debugging advice. Just picked up a ndac (from one the guys on here) and it’s working beautifully except for a hissing on the left channel. The hissing is only present when the dac is connected. Switch it off and the hissing goes away. I’ve removed as much as possible possible sources of interference and no improvement. Also moved the input (optical) to each of the 4 dac input options, as well as moving the snaic around the preamp input options and those variables don’t make any difference.

Before going down the repairing option with the ndac is there any other debugging ideas out there that I should look at?
 
Do I understand correctly that the hissing is present even when you use another source, just as long as the DAC is connected and powered on?
Try it with an extention cable from another outlet and/or (try all 4 options) use a different optical interconnect.
Can you try another type of output on the DAC? Analogue?

What I don't understand is why you would connect a DAC -digitally- to your pre, that seems to make it rather pointless doesn't it? I'm probably missing something obvious here, but the coffee hasn't sunk in yet.

I'm a bit confused: it seems like electronical feedback if the hissing is there even when you use another source, but an optical cable shouldn't have electric coupling, so that seems very odd. I need more coffee
 
It's either your source, the dac or your choice of connections. Change them all one thing at a time.

My money is on it being connections.
 
Tin said:
Do I understand correctly that the hissing is present even when you use another source, just as long as the DAC is connected and powered on?
Try it with an extention cable from another outlet and/or (try all 4 options) use a different optical interconnect.
Can you try another type of output on the DAC? Analogue?

What I don't understand is why you would connect a DAC -digitally- to your pre, that seems to make it rather pointless doesn't it? I'm probably missing something obvious here, but the coffee hasn't sunk in yet.

I'm a bit confused: it seems like electronical feedback if the hissing is there even when you use another source, but an optical cable shouldn't have electric coupling, so that seems very odd. I need more coffee
Click to expand...

Thanks for the responses guys, much appreciated.

Hissing is present only on the channel the dac is connected to and it goes if the dac is powered down or removed. When th dac is connected and powered the hissing is present irregardless if the dac has an input connected itself. The dac is connect to the pre’s analogue inputs. Hope that clarifies.

Will try to find another snaic as the next step. Thanks guys.
 
So basically it sounds like the left channel out of the DAC is noisy, which would suggest it's got a fault. I'd be really surprised if a different lead will make that go away, as leads will normally work/not work, or if wired incorrectly introduce a problem like an earth hum.

I'd be booking it in for a repair.
 
Just to clarify, if you're looking to get another cable, it's an interconnect that you require for connecting the analogue output of the DAC to the pre-amp, not a SNAIC; the latter carry signal and power.
 
asmith17 said:
Thanks for the responses guys, much appreciated.

Hissing is present only on the channel the dac is connected to and it goes if the dac is powered down or removed. When th dac is connected and powered the hissing is present irregardless if the dac has an input connected itself. The dac is connect to the pre’s analogue inputs. Hope that clarifies.

Will try to find another snaic as the next step. Thanks guys.
Click to expand...
It clarifies it. Second coffee helped also. :D
I'd still try switching interconnects and putting the DAC on another outlet, but as its only one channel, my gut feeling thinks its the DAC itself.
 
Thanks again. Swapping the cable had no effect so looks like back to the repair options. Thanks all though for great support.
 
The nDAC uses the PCM1704, which is not prone to going noisy.
Has anyone been messing with the output filter, rolling opamps, boutique capacitors etc?
Digital faults are not normally subtle.
 
Will you be speaking with the vendor? I bought a phono stage from someone on here and he ducked and dived when I mentioned that it didnay play pleasantly. I ended up buying another. Not bought anything from a private sale on here since.

Did it develop this hiss in transit?

Can we say such things on here? Haven’t identified who have we. Best of getting joy from the DAC.
 
just to follow up on the latest comments and thanks guys keep them coming.

No know changes/modification have been made, so it's a mystery why there's this hiss. I've debugged it as far as I can so the next steps are getting someone to have a look at it.

In terms of the vendor. Already spoken and discussed the issue with them. Have to say it has been a delight. They have been tremendously supportive and have offered to have it all sorted. We just wanted to make sure I wasn't doing something stupid with it before going down that route. Really impressive guy.
 
asmith17 said:
just to follow up on the latest comments and thanks guys keep them coming.

No know changes/modification have been made, so it's a mystery why there's this hiss. I've debugged it as far as I can so the next steps are getting someone to have a look at it.

In terms of the vendor. Already spoken and discussed the issue with them. Have to say it has been a delight. They have been tremendously supportive and have offered to have it all sorted. We just wanted to make sure I wasn't doing something stupid with it before going down that route. Really impressive guy.
Click to expand...
In which case accept his offer to sort it.
 
Just a thought, did you try both positions of the signal ground switch (Chassis / Floating)? I've had nDAC since 2011 and have never experienced any issues with the outputs. Hope you get it sorted out!
 
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