Rossini vs. Preamp Volume Control and Setting

dCS Products
1

Hello,

My Rossini is currently feeding (at full volume) a Soulution preamp. At one point, I did experiment without the preamp in the path, however, to my ears, with preamp sounded better.

My question is this. Now that i’ve settled on a preamp in the path, do the Rossini volume settings matter? I’ve read on a few publications that it’s better to let the preamp do as much around volume control. Also, in theory, the lower I set the Rossini volume, the less work it has to do and the more it can concentrate on D/A conversion?

Thanks,
Udi

2

Check out this discussion regarding volume control and preamp

3

You should set the Rossini to full vol. do not turn the vol down on the Rossini, otherwise you will loose bit depth resolution!
You can clearly hear the difference with your own ears.

Also set the Line output from Rossini to 6 volts in setup meny for the best S/N ratio possible.

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4

I would not recommend doing that by default! Some Pre-amps can overload as they have input sensitivity of just 2V.

I would highly recommend people read the dCS manuals, there’s a clear warning;

5

Thank you for this. I did notice this warning in the manual and set my line output to 2v. So, otherwise, everyone agrees that setting the Rossini volume to maximum is likely to yield best SQ?

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6

In my opinion, the best SQ would be achieved by checking what’s the exact input sensitivity of your particular Pre-Amp and then matching to that as closely as possible on the dCS DAC.

7

Digital volume controls work by “discarding” bits.Therefore when set at 0.0 nothing is discarded and you have maximum resolution. However it is unlikely that you would actually be aware of any subjective loss of sound quality until the reduction in level below 0.0 is significant. By then, however, the loss of volume may be such that you would not actually be aware of the quality loss. I have listened and listened to the effect on sound quality that setting the control well below -20dB brings and , frankly, have nothing to report. It just sounded quieter as it should.

As for the voltage settings these are limited in scope on the Rossini and exact matching rather than approximate matching is not possible. The 0.0 figure refers to dBfs ( decibels full scale). That is if the programme material has a section at the maximum recordable level (0.0dBfs) then the Rossini will put out a voltage of 2 or 6 volts , depending upon your voltage selection. Of course the actual voltage level will vary in accordance with the recording level moment to moment and a 2 or 6 volt output may rarely or only briefly be encountered in practice ( partly depending on genre of music).

That figure of 2V and the recommendation to use it is not a random figure but is based on the industry standard for the voltage that CD ( and SACD) players should produce for a recorded level of 0.0dBfs. The majority of modern preamp line inputs are designed with something around that figure in mind for sensitivity. The need for 6V for a line input on a preamp would be, IMO, unusual. It may, however be appropriate for certain tube power amplifiers with comparatively low input sensitivity and where the DAC is directly connected ( no preamp).

Some old preamps, mainly dating from before the CD era, may overload even with a 2V input. dCS does cater for this circumstance ( and for some power amps with very high sensitivity) with e.g. the Vivaldi DAC which also offers outputs of 0.2V and 0.6V for 0.0dBfs recorded level.

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8

Just to add I have tired the Rossini direct in to the power amps (balanced) at 6v and it sounded great. By the way, 6V is better sounding than 2V. But the same into the Preamp albeit single ended was just a little better. So, I’m sticking with my Preamp with the Rossini set at 0dB.

9

You may find it so but that is not a universally applicable conclusion. It will vary for person to person and system to system. For example with my power amps and their 0.5V input sensitivity it would be impossible to use a 6V setting in practice without the volume control turned down to a level where a possibly audible loss of resolution would occur or by using an in-line attenuator, the latter a great way of screwing up the sound from my experience.

I am sure that dCS would tell you that the output signal at 6V from the DAC is identical to that at 2V except 7 or 8 ( or whatever the number is) dB higher.

10

Yep, agree with that.

Just what I am hearing.

What I love about the Mosaic app is that there are many settings I can try towards finding what feels good to me in my circumstances :slight_smile:

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11

Yes, but you will get the highest SNR ratio nevertheless, it is also confirmed in the Vivaldi DAC manual under Specifications where you only get the highest SNR output with 6 volt output .

You will hear distortion if you over-steer the input stage of the pre-amp.

If you turn down the digital volume to - 40 or -50dbs you can defensively hear the loss of bit-depht in form of digital distortion artifacts, but like dCS have stated the digital volume is pit perfect from -20db - 0db

12

@PAR

As I’ve mentioned on this forum a number of times, I’ve always used my Rossini as a pre-amp direct to my Boulder 2060 amp and have enjoyed the transparent sound this results in as many people on this forum have pointed out. I always pay attention to the Rossini voltage output level so I can run the Rossini volume control between 10 - 0.

However, I recently purchased Magnepan 20.7’s and thought they didn’t do well at low listening volumes, A friend of mine that also has the 20.7’s suggested a pre-amp might add a bit of punch at low listening levels so I gave in and purchased an Audio Research Ref 5 SE.

First thing I noticed was that I needed to turn down the gain of my sub-woofer with the Ref 5 SE. That gave me an indication that the Ref 5 SE was doing something that resulted in boosting the output signal.

I’ve only been listening for less than a day but the Ref 5 SE took care of low listening levels as it introduced more punch, kind of like the ‘loudness’ button we experienced on receivers back in the 70’s. And the best part is that it doesn’t appear I’ve lost much if any transparency.

The funny part is that a couple years ago I tried Audio Research’s flagship Ref 10 and it seemed to darken the sound so I went back to going direct from the Rossini. Perhaps a system synergy thing.

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13

I love these forums — such well-written, friendly input. They’re not all like this! Figured I’d chime in and bring it down a couple of notches :slight_smile:

I’ve just finished up a weekend of comparisons with my Bartok, and the results really surprised me, because it’s the first time that going direct to a power amp has come out ahead for me.

I had had a good go before with my Ayre QX-5 Twenty (now departed), but it was never even close. I lasted a few tracks then swapped the preamp back in. It sounded thin and my mind kept wandering to other things, which is hardly why we spend the time and effort…

What prodded me into seeing how I would feel going direct with the Bartok was reading this:
http://www.enjoythemusic.com/magazine/viewpoint/0601/audiohell.htm

It’s a slightly different approach to drawing comparisons, and while the writing is a bit over-the-top in places for me, there was a fantastic nubbin in there that I’d not heard before — that listening to the same reference tracks over and over can serve to nudge our perception of our current system’s sound into a cosy feeling of familiarity, and therefore something we enjoy. (My other half likes the way I look, but I’m sure I’m an acquired taste!)

I’m not for a moment suggesting I’m about to start listening to music that I don’t enjoy, but it was a total revelation for me to use unfamiliar tunes as I compared the system both with and without the preamp:

dCS Bartok
– Tellurium Q Silver Diamond (balanced)
(Pass XP-30 preamp)
– Tellurium Q Silver Diamond (balanced)
Pass XA60.8 mono-blocks

More often than not (80+% of the time, probably), with new music, it was going direct that sounded better to me. It wasn’t just that it sounded better in passages that I was ear-balling critically, either. Perhaps even more importantly it was the same when I wasn’t paying too much attention — just relaxing into the music.

I had another go this morning with some properly quiet-LOUD-BANG-CRASH dynamic things, and it was similar. Maybe ever-so-slightly more bangy and crashy via the preamp, but only ever slightly, and generally at the expense of something else. I don’t feel like I’m losing dynamics.

The only time there was ever the hint of something that I’d like to lift and shift from the sound I got with the preamp was with some vocals, when the preamp filled things out just a smidge. Only a smidge, though, and again, generally at the expense of something else.

Colour me surprised.

For what it’s worth, I used the following settings:

Direct: Bartok set at 0.6V.
My first lot of comparisons were done at -20dB on the Bartok, my second at -10dB.

With preamp: Bartok set at 2V.
Levels matched with what the settings above gave me.

Does make me wonder whether going to the Rossini or the Vivaldi one day mightn’t be a good idea…especially with the new funds from the preamp :smiley:

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14

Thanks for sharing that link. Perhaps a bit over the top, but still interesting. Abstractly, I like the idea of “comparison by contrast.” I am not sure it will inherently produce the most pleasing system, but theoretically, it should lead one to the most revealing. But I am still digesting, and plan to re-read and consider it. In the meantime, I am going to enjoy some music.

15

Digesting is exactly the word, Greg! I must have read that article half a dozen times. It eventually clicked, and the enduring takeaway for me was that I’d been honing my system for a few reference tracks.

Interestingly, I’ve since been happily ploughing through tracks from when I was a kid, as well as letting Roon Radio do its thing with lots of new stuff. I’ve spent what feels like more time enjoying myself. While small parts of some tracks occasionally sound ever so slightly less incredible than before (i.e. the preamp improves them), on the whole the system is exactly what I was hoping for — a happier place to soak up the majority of the music I listen to.

As if I’ve turned out of a very comfy cul-de-sac of familiarity.

Would love to hear how you get on. I’ll get back to some listening now too :smiley:

16

Ben, this is another thumbs up for Roon Radio. I love how much new stuff it has helped me discover. With my system where it is now, I am not all that concerned about comparing it to the “latest/greatest.” I am very happy with its resolution, and what sounds, to my ears, like something very realistic. The one difficulty I perceive in the “comparison by contrast” approach is that it might be more difficult to employ in an upgrade setting. When one is at the dealer—and let’s hope it is a dealer with wide-ranging inventory—and comparing several choices of equipment, the “CBC” approach makes perfect sense, both abstractly and pragmatically. In fact, one might well argue that when starting from a blank sheet, CBC is inherent to the process. But when one is enticed by a dealer or friend to go hear the latest/greatest, what should one do? How does one not make use of comparison by reference? In my system, Peter Gabriel’s Mercy Street sounds a certain way. When I go to the salon, I can know how it sounds in my home; is it really so difficult to employ both CBC and CBR at the same time? Does CBR truly keep me from saying: “Wow, I never heard that bass note that way before!”? I don’t think so, and as I consider the notion, I would say that any good listener probably employs, or should employ, both methods in the same evaluative scenario. It might even be more difficult not to.

I don’t know, as I consider it, I am starting to wonder if this might be a bit of a false dichotomy. Just my two cents; still fun stuff!

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17

I’m with you — it’s an AND rather than an OR. Just that for me it’s been an AND that has helped my sanity enormously.

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18

That makes perfect sense.

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I think this is an important point. Audiophile forum contributions can read as if fidelity is the goal irrespective of enjoyment. I wouldn’t argue against a revealing system; I would argue for one most pleasing to me.

20

:+1: :+1:

There could be a very tedious philosophical argument started here. I hope not :thinking:

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