I want to bypass my preamp and use my dCS Rossini apex with clock straight to a pair of Nagra Vpa monoblocks. So as not to create a stress mess, I am asking what if any settings need to be changed in the Rossini.
ThankYou
Mike Garver
The only thing that comes to mind is that you need to ensure that the line output voltage of the Rossini is correctly selected for the input sensitivity of the Nagra amplifier(s) This amp has an input sensitivity of 400mV for maximum power output.
When using the Rossini direct then its volume control should not indicate attenuation greater than around -30dBfs for an average decent listening level and something less may well be preferable for you.
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Yep, as Pete says 
And if you want a calm, safe, step-by-step for when you get into the setup I’d do this:
- Start off at a whisper by setting the output of the Rossini to one of the lowest options (0.2V or 0.6V, which you’ll find in Audio / Line Output).
- Turn the volume on the Rossini down nice and low (-50dB or something).
- Hit play.
- Turn up the Rossini until you’ve got tunes.
Fine tune from there. As Pete says, you want step 4 to have you in a range that’s not too attenuated — something like -30dB–0dB is good. You’ll get that by twiddling the volume knob and moving between the 0.2V, 0.6V, 2V and 6V steps in Mosaic.
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In case it is helpful, dCS Rossini manual page 10:
"Using a power amplifier directly:
• Set the DAC’s Volume to around -40.0dB as shown on the display.
• Connect either the balanced (XLR connectors) or unbalanced (RCA phono connectors) outputs on
the DAC’s rear panel to matching inputs on your power amplifier. Switch on the power amplifier.
• Turn the DAC’s rotary control slowly clockwise until the music is at the right level.
• If the Volume setting for a comfortable listening level is higher than –10.0 or lower than –30.0, try
changing the Output Level setting.
• Press the buttons in this sequence: Menu, ►, ►, Menu, ►, Menu.
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I now run my Bartok direct into my power amp. The amp has an input sensitivity of 2V for 100W. In my setup running 0dB at .2V output is generally loud enough. When I need to crank it, -3 to -6dB on the .6V output setting works. This amounts to about 1W to10W of output on 0dBfs signals
Everyone will have different needs, I listen mid to near-field in a room with fairly low ceilings, hence the need for little power.
Subjectively I prefer running direct. The sound appears to me to be more transparent. Although I do occasionally miss the extra weight in the mid bass when using my preamp.
thanks to both!! I am looking forward to trying this
Mike
HI all, looks like my new D’Agostino S350 Stereo amplifier will be here next week (they ship via aircraft don’t they?). May I ask some owner if I should set my Rossini DAC output at 2V or 6V? Of course I will start with the volume at -50dB.
In other words, is 6V compatible? Won’t it oversaturate?
Thank you
A.
I was curious of the setting myself, so, I asked Dan at D’Agostino as I’m running my Rossini APEX DAC thru a Progression preamp > Progression monos and he stated 6V on his dCS gear. I do have the balance at -15db. I’m quite satisfied & put the issue to rest.
I believe Dan ships exclusively with FEDEX (Ground for USA and assume Air for International). Could be wrong about the International.
Congrats on the S350 – brace yourself. 
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These sound like great systems
Just a short note to say that I would not start at 6V if you’re going direct to power amps. The note above from @honchi is a bit ambiguous — it’s one thing to say that Dan goes direct to a preamp at 6V and another to say that he goes to power amps at 6V.
I don’t think I’ve ever turned a preamp up to full volume with any of my power amps, which is the equivalent of what you’d be doing if you (or someone else) turned your dCS to -0dB. Likely ok at 0.2V, likely not ok at 6V. I’d start things off a bit less hot, as I wrote further up. Mind you, perhaps that’s what Robert meant by “Brace yourself” 
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First off, follow the manual. I have the Bartok and use 6v directly to the DD Progression amp and 2v when using the DD Progression pre-amp. FYI, I prefer it with the pre-amp. I’m in the queue for the Apex upgrade and will try it without the pre-amp again. I REALLY want to ditch the pre-amp because I only stream Qobuz.
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I have tried 6V from my Vivaldi to my Momentum HD pre but prefer 2v. With 6V normal listening volume is achieved at a point so low on the volume knob that in my case does not leave sufficient room for minor adjustments.
That does not apply direct to amps since you will be using the Rossini’s volume control. It’s just a bit of info why 6V may not always be the answer.
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Thank you, so I understand that the Progression S350 amp accepts a 6V input (I will start with 40dB attenuation as recommended of course).
Looks like next Thursday is the day.
On a tech note: the difference between 2V and 6V should be
20*log10(6/2) approx equal to 9.54 dB
is that right? So I should achieve the same spl with 2V and -10dB as with 6V and -20dB?
Since we are here, I will obtain 6V from my Rossini if:
- the output is set at 6V and
- the volume setting is at 0 dB attenuation and
- the digital signal is “all bits on”
Is that right?
Thanks
A.
Back to the Future, the scene with the guitar and all potentiometers full right …
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going into a pre amp you will get 6V out on the 6V setting with a 0dBfs signal. Going direct into you amp at 6V / 0dB might break your speakers!
For what it i worth I run my Bartok on the .2v or .6 v setting into my Bryston 3B(3) amp direct. In my room with my speakers I can run the volume at 0dB on the .2V setting and -10 to -3dB on the .6V output to get things satisfyingly loud. So i’m using milliwatts to about 10w max! I find running -10-0dB on a lower voltage setting seems to sound better to me that running 6V at -40 to -30 dB or 2V at -30 to -20ish dB
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