AV Fixed Volume custom level

If you getting excessive hiss with nothing even connected then its either faulty or your speakers are just not a good  match to the Atom or the Atom is not a match to your speakers. I hear absolutely nothing on mine with AV fixed volume. Have to go up to the tweeter to notice anything, As a matter of interest what firmware are you on? The latest 2.6.2314 build 4658?

 

Speakers are Focal Chorus 826V from the same company... FYI, the sensititivy of this speaker is 91.5dB.

The firmware version is 2.6.1.9794 and it says it is up to date in the app.

I don't know what to do.

And how does Atom sound when you disconnect the AV unit and use one of its other inputs?

Is the hiss audible when you listen at normal volumes?

There is a reason behind these questions, so please let me know

Andy76 posted:

Hi , Just to add, I also had hiss when AV fixed volume setting on my Atom. Also present when not connected to the AV amp. Also found reducing volume helped as per the original post but not sure if this can be changed as a default. 

I have recently had a few amps in my room: Cyrus 8A, Nad C 388 both have an Av bypass mode and neither had hiss as notable as the Atom all other equipment the same. 

At present I am only running 2 speakers so I stopped using the Av amp and not sure I could live with the hiss if I had a 5.1 set up again. 

Thank you for sharing. What were your speakers out of curiosity?

Adam Zielinski posted:

And how does Atom sound when you disconnect the AV unit and use one of its other inputs?

Is the hiss audible when you listen at normal volumes?

There is a reason behind these questions, so please let me know

Other inputs are always ok at normal volumes, even with the AVR connected.

Audible hiss from listener's position = only in AV Fixed volume for analog input, whether something is connected to the ATOM or not.

My diagnosis is that you have a ground loop between your Atom and the AV unit.

There is a simple and cheap solution for that - audio isolation transformer. It’s inserted between the audio outputs of your AV unit and inputs of your Atom. 

I use one of these myself - it’s dead quiet and given my setup with multiple connections it’s a the only way to tame it. 

Adam Zielinski posted:

My diagnosis is that you have a ground loop between your Atom and the AV unit.

There is a simple and cheap solution for that - audio isolation transformer. It’s inserted between the audio outputs of your AV unit and inputs of your Atom. 

Thank you for your suggestion.

I have already tried that, even though I'm pretty sure it is not a ground loop.

Indeed, even when the AVR is unplugged electrically & the ATOM isolated (ie not attached physically to anything except power & speakers), the hiss is audible in AV Fixed Volume with analog inputs.

My diagnosis:

- The ATOM introduces the hiss when in AV Fixed Volume because it goes into full amplification. This is either something normal on all Uniti Atom and the association with my speaker is not ideal, or my unit has a defect. 

- The true workaround: decrease the amplification factor in AV Fixed Volume so that equals the one when the volume is set at 75 (threshold from which the hiss becomes noticeable at the listener's position). This is currently impossible to do by the end-user.

- The dirty workaround: disable AV Fixed Volume and set a volume of 75 for the analog input. This is a shame as there is no bypass of the pre-amp section of the ATOM, plus the constant volume change when switching to another input.

My biggest frustration is that all the limitations encountered for me can be solved by software (this fixed volume issue, turning the display off for analog input after x min, or the ability to control the unit with something else than the remote for better integration in a complex system (IP, JSON, Logitech Harmony, IFTTT, whatever)).

Quite honestly, I was expecting better from a software point of view for such a product.

Perhaps you should the take it to your dealer and have it checked, rather than jumping to conclusions?

ardemk posted:

Andy76 posted:

Hi , Just to add, I also had hiss when AV fixed volume setting on my Atom. Also present when not connected to the AV amp. Also found reducing volume helped as per the original post but not sure if this can be changed as a default. 

I have recently had a few amps in my room: Cyrus 8A, Nad C 388 both have an Av bypass mode and neither had hiss as notable as the Atom all other equipment the same. 

At present I am only running 2 speakers so I stopped using the Av amp and not sure I could live with the hiss if I had a 5.1 set up again. 

Thank you for sharing. What were your speakers out of curiosity?

Hi, I was (and still am) using Kef LS50 with all 3 amps. Must say, currently don’t feel I’m missing 5.1 that much as the Atom sounds so good in stereo for TV, but bass management when using a receiver was handy and a little missed. 

I'd like to add that I am experiencing exactly the same issue as the OP.    My Atom has never hissed before. I recently started using it to power my front speakers in AV bypass mode using a Denon AVR as pre-amp.  When the analogue input of the atom is selected, there is a clear hiss close to the speaker (mainly tweeter) which is still, but only just, audible at the listening position (around 2.5m away).  The hiss is present regardless of whether anything is actually connected to the analogue input. The hiss is not present when any other sources (e.g. spotify) are selected.

In my case the hiss is more of a curiosity than a distraction. It is only just audible at the listening position and is easily masked when any content is playing. 

ARDEMK -- did you ever get a response to your email to Naim support?

Hello Radeber,

No answer from the Naim support team, even when my request has been transferred to the technical department.

My workaround is to set the volume manually to 75 for the analog input, and counterbalance with the auto-calibration from the receiver (Audissey XT32).

The painful thing is that you need to turn the volume down before switching to an audio streaming input such as Spotify. 

I just changed my speakers to Tannoy XT6F and I now can hear the hiss when using AV Fixed Volume, never got it with the other speakrsp. These must be a lot more sensitive. It's very noticeable from my viewing position.

Welcome to the club

Maybe I'm dreaming awake, but what would be nice would be to be able to assign a fixed amplification level, even if not bypassing preamp, so that we get rid of the hiss :/