I like to run my Lina DAC straight into a Naim nc 250 with balanced outs @6V and listening between -44 dB to -20 dB for optimal sound quality. I am afraid of someone inadvertantly cranking something full blast when I’m not there. Anyone else facing this same low level anxiety? Seems like a feasible firmware implementation, perhaps?
Feedback invited.
Best wishes,
Eric
Running you system with the maximum line voltage of 6v then needing to set the volume control as low as -44dBfs indicates that you have set the line voltage too high for your system.
You want the volume control to offer a range that is easily controllable. A high line voltage then dropping it by lots of attenuation by the volume control is self defeating as your power amp is receiving the same result as using a lower line voltage but with the volume control range less optimal for practical use.
The answer is to use a lower line voltage.
dCS actually advises to use the lower output levels 0.2 or 0.6V to be used when streaming AirPlay over a direct-to-amp connection:
My car has a valet setting which limits things, so some type of safety/guest setting for airplay?
Hi Eric,
I have 250’s and 300’s myself and if you are running NAP250’s with the Lina set to 6v output then they will be driven to clipping by a 0db source at about -12db on the volume control so my first suggestion would be to drop back to the 2v output setting (that drops the output level -10db over the 6v setting) so that you have much less chance of clipping your 250’s anyway, this would bring your normal “operating range” to roughly -30 to -10db.
However, and as @Ermos has already mentioned, the 0.6v and 0.2v settings will additionally drop the maximum output level by a further -10db and -20db respectively and will help prevent any issues with overzealous Airplay usage … the output level can be selected from within Mosaic and cannot be overridden from Airplay itself so makes a very effective (and foolproof) volume limiter.
I hope that helps.
Phil
Exactly. I know I can drop the voltage, but I don’t want to because I found a sweet spot. I’d prefer to stay with that setting and not have worries. Just a bit of streamlining is all I’m after really.
Thank Phil,
I pretty much re-derived your setting values through my own listening, so I get you there. As August implies, maybe this is a bit of a luxury ask, but also practical.
Pete,
Many on this forum experience degradation at lower voltage settings, as do I. dCS assures no degradation in digital attenuation around -40dB. I think the choice of operating range is more open than you assert.
Eric, that you should use a lower voltage has been suggested to you by three of us; Phil, Ermos and me. As one of the audio designer greats once said to me “ If you don’t like the answer, why ask the question ?”.
The volume control range that you CAN use is not the same as the rage that you SHOULD use to deal with the issue you originally raised. Also note Phil’s comment regarding 6V with a NAP 250. BTW, he knows what he is talking about as his previous job was with Naim.
Pete,
If I understand you, you are letting me know that my feature request to improve the functionality is invalid, because the old way of doing it already exists. That’s very forward thinking for a response to a new feature request, not. I think you may have missed the gist of my question.
I think it is a reasonable proposal for a small evolutionary improvement.
Hello Eric,
Yes, your enhancement request is fully valid. Having a way to set a maximum volume threshold via Mosaic App and dCS control boards should be possible.
Now, Pete and Phil comments are valid as well: it looks like your current sweet spot is not appropriate for you amp. If using your Lina as a preamp your amp is clipping when you go above -20dB, the output level is incorrect.
Moreover listening below -30, and even worst below -40dB, you have signal degradations.
If your amp clips at -20dB with output set to 6V, best would be to try setting the output level
To most of people here, me included, dCS DACs volume sweet spot is in the -30 to -0dB range…
My two cents,
Erwan
Erwan (Pete, Phil too),
On this forum, it has been asserted that the S/N of the 6V output bests 2V by ~8 dB (per Hi-Fi news measurements). It has also been asserted by Andrew S, on behalf of dCS, that the digital attenuation by dCS in the volume control has no degradation of quality down -40 dB. And, it has been asserted that the proper voltage for the amplifier can be obtained through the combination of output voltage and digital attenuation in a continuously variable way.
So taking these propositions together, what am I missing? I am talking about tickling the transistors in my rig, to my satisfaction and then wanting that to be my new normal range, with a safeguard.
I can’t understand why the suggestions here completely bypass these concerns/realities. You guys are not seeing your own blindspots, perhaps.
Well, some prefer 6V, some don’t.
I prefer 2V for example.
There’s no best, regarding the output level, there’s a preference for some, and a coherent setting with the rest of your system for the others.
Now, if this preference leads to some inconsistency/discomfort/risks… for your ears or the rest of your system, best is to change your settings a bit.
To me, safer to have a setting that will never make your amp clip, and my preference to have a preamp setting a comfortable, loud enough actual volume with the knob at 12 o’clock, rather than having something already too loud at passing 9 o’clock…
My two cents,
Erwan
Thanks for the feedback Erwan, appreciated, but I think we are not yet on the same page here. I am living in a hi-fi world beyond knobs. Maybe my thoughts will sink in over time.
Ok, let me rephrase it. 
It’s no issue and even desirable for many to reach a comfortable loudness by pushing your preamp pretty high.
Again, not an issue to have your settings made so that your default low listening level is there at a high -30dB or -25dB.
You won’t lose any definition at those levels, and if the output settings is set accordingly, no risk for your amp/speakers either.
Yes, exactly. Now what about protecting that range of settings from being subverted by an unwitting guest with an iPhone?
That is the crux of my request, not to understand how to provide the correct voltage to my amp.
For example, I want to set the Lina to never output more than -20dB at 6V, no matter what, until I change the limit through the front panel. That would take care of my issue just fine.
Again, I think your enhancement request is valid.
And again, I see two different issues there… why not give a try to the settings change we proposed for the second?
Have a nice evening/day/night wherever your location is.
As Eric says, having some kind of safety feature specifically for direct to power amp users would be nice @Phil
