Hello, I am using the Vivaldi DAC. I have just swapped my pass labs preamp for an Audio Research ref6.
I find that using the 2v output I have to keep the preamp at half the unity gain, and I wanted to keep the preamp closer to its unity gain.
I understand that lowering the output to 0.6v, I will have an attenuation equivalent to aprox 10db, which would be sufficient.
I wanted to know your experience in using this 0.6v setting and confirm that I will suffer no sound quality penalty, and that the SNR is maintained in this setting.
The 0.6v setting is primarily in place for use with Airplay. I don’t know of anyone using it for normal listening.
You have too much gain in your system for what you’re trying to accomplish using any normal settings so you need a volume control somewhere. You can either use the VC in the REF6 as intended (being close to unity gain isn’t really critical since the VC isn’t adjusting gain, it’s just attenuating the signal) or you can set the REF6 to unity (or theater bypass) and use the VC on the Vivaldi.
I run without a preamp so I obviously use the VC in the Vivaldi. I have zero complaints with this setup and have no desire to add a preamp.
I’m curious, why would one want to run the Ref 6 pre-amp at close to 100% volume? I have an ARC 40th Anniversary Reference Pre and I found that my system sounded quite a lot better with it in place as opposed to bypassing it and running my Vivaldi straight into my D’Agostino M300s. I have played around with volume settings on the DAC and I find that running it at 0dB and 6V gives me the most dynamic sound. I tend to run my pre-amp’s volume control at 30 - 40. Won’t running the pre-amp at unity gain (100%) shorten the life of the tubes?
I don’t think anyone will run their pre-amp anywhere near full volume be it the Ref 6 or other. Before I swapped out my original Momentum pre-amp for a newer HD version I had set my Vivaldi DAC to 6v. With the changes in the HD model I find it better with the DAC set to 2V. With this setting I am nowhere near having to set my pre-amps volume even close to half way, maybe 1/3.
If I remember correctly your Ref Pre will display ~40db under normal circumstances
At that time, I was.experimenting with the digital x analog volume controls. I was also following the trail of common lore, that you should try as much to keep equipment near their unity gain, so that the pots are mostly out of the way. And that was my experience. I never got to a point where I was completely satisfied with the ref6.
From that time, I upgrade to a nagra hd preamp. All is solved now. The volume control implementation is terrific. I keep the vivaldi at 2v, to match the input sensivity of the Nagra and never think about it anymore.
Hi Jim, thanks for the reply. Actually, the Ref 40s volume control starts at zero and I think goes up to 100 (but I’ve never pushed it up that high). The highest I’ve had it was 70 and that was for some very quiet Reference Recordings pieces. I tried it last night at 2V and found it to be quieter by about 20 points on the volume dial and less dynamic. So, it’s back to 6V.
I’m also interested in the fact that you have the Momentum HD pre-amp. I added the M300 monos last September and was blown away by the increase in dynamics over my Bryston 28B monos (which are rated at 4x the output power of the M300. I’d like to try the Momentum HD pre but my dealer tells me that I would be hard pressed to improve on the Ref 40. Can I ask what you had before the D’Ag pre-amp? Realistically though, I think that a Vivaldi Upsampler and Master Clock might be the better path to follow.
Your experience with the improvement in dynamics when inserting he M-300’s into your system is similar to what occurred when I replaces the ~1200 wpc McIntosh 1.2k;s with M-300. At the time my speakers were MBL 111F’s and the 300wpc Momentum’s gripped the MBL’s so much better that I actually though I must have been listening for a few year with them connected out of phase. I went thru a few pre-amps including both tube and solid state before picking up one of the original Momentum pre-amps. A few years later I had the opportunity to purchase a pair of Momentum M-400’s in black which was a nice yet subtle upgrade. During a event at my dealer I had a lengthily discussion with Dan D’Agostino regarding the improvements he had implemented in the HD version of the Momentum pre-amp as was developing the new pre to match his Relentless amps. I decided to bite the bullet and order a new black HD pre to match my amps rather than upgrade my silver one. When the new pre-amp arrived I was stunned that the new pre-amp seemed a bigger upgrade than the move from the M300 to the M400’s.
There are a lot of individuals like yourself who like a tube pre in there set-up and if I were you I would borrow a demo HD version to see if it meets your needs. Fortunately I have a dealer who allows be to A/B anything in my set-up.
Hey Jim, thanks for the reply and your valuable insight. I’m actually not married to the idea of a tube component, it’s just where I ended up. I actually don’t like the idea that the tubes slowly degrade with use and require replacement every ~2000 hours. I would love to not have that hassle but the “bloom” offered by a tube pre-amp does add some magic (2nd order harmonics?) to the sound. I would also love do a home demo of the HD pre in my system but I’m hampered by geography: there is a D’Agostino dealer about 200 km from my house but I have an 18 year relationship with a dealer who is about 2500 km away (I moved). I don’t want to waste the time of the local dealer only to then buy somewhere else - not cool. But, I will sort that out eventually. My impetus for doing the M400 upgrade is that these amps were used and there is a noticeable transformer buzz coming from one of them and the power meters also seem to be out of calibration. So, as they need to go back to the factory for a check-up anyway I thought it would make sense to do the upgrade at that time. Thanks again and stay safe in these crazy times
That figure would not be realistic in general with small signal tubes and is more applicable to power tubes. 10K + hours is not unusual with preamp tubes and longer usage can be found. However and putting aside gradual degradation tubes are, of course, ultimately less reliable than transistors. It all depends on what you are aiming for. I would rather have the performance I want for several years at a time rather than something less satisfying for eternity.
You could give the nagra a try. It has tubes and wonderful dynamics. I know people that have up the momentum for the Nagra, and never looked back. And yes, the tubes are 10k hours rated
A Nagra HD preamp and a dCS Vivaldi…hopefully it solves the problem …otherwise you would be in big troubles unless there are some hifi shop on Mars
Hey everyone; thanks for the reply about tube life. ARC recommend replacement of the power tubes every 2000 hrs and signal tubes every 4000 hrs. There are four power tubes and 8 signal tubes so that does tend to add up if one is buying good quality tubes. I hesitate to think that their recommendations are atavistic, perhaps just leaning toward a more conservative approach. I have heard an improvement in the sound when I have replaced my tubes at the recommended time intervals but I agree that tubes should last longer than that. I will experiment with this at the time of the next scheduled tube change.
As for the Nagra HD pre, it looks quite interesting and I’m sure the sound is stunning but I have not had any experience with that brand and I think that’s a bit rich for me at this time. I’m pretty happy with my ARC pre-amp otherwise, it’s the forerunner of their current Ref 10 and my dealer tells me that mine has the superior sound of the two. Perhaps I’ll circle back to the pre-amp when I’ve finished with the Vivaldi trio
What is the best value for output voltage on Bartok? If I use the dac directly to ATC SCM 50 actives with a 2v gain, then I use the range of -30-20dB, usually -25dB volume level.
If I set 0.2v, then I can completely bypass the digital adjustment and set the volume to 0.
What will be better - digital attenuation ~25dB at high gain or a decrease in digital attenuation at low gain?
Sorry to but in as you are specifically asking Andrew but the answer to your question will partly depend upon the age of your ATC 50As.
The power amp sensitivity on earlier models, albeit with the later tri-amp design ( post late 1993), had a rated input sensitivity of 0.5V. Later models changed this to 1V though I am unsure of the date when this commenced.
If you set the Bartok to 0.0dB with no preamp then clearly 6V output is too great for this input sensitivity and 0.2V is too low and 0.6V marginally too low. So 2V is possibly the best choice. Although this may seem to offer a chance of overload this will not happen in practice as the difference between 1V ( ATC input) and 2V ( Bartok output) is only 6dB which the overload capacity of the ATC amp should easily cope with without going into audible distortion.If it is too high then the amp is designed to self limit in order to avoid harm though it is preferable to avoid this limiting. However it could also put the active speaker at nominally full output or circa 112dB given a recorded signal of 0.0dBfs . That is dangerous for your hearing . Fortunately few recordings are made with a continuous 0.0dBfs level. But even given that the disc may keep a few dB in hand to avoid running out of bits and the resulting distortion ( a very few dBs with a lot of post millennium rock recordings ) the result could still be ear damaging.
OK, so instead of 2.0V you move to 0.2V. But without a preamp and with the Bartok set at a fixed 0.0db you then have no way of altering the volume which will then depend upon the recording level of the programme material. This will vary from disc to disc. So I do not see the practicality of using a fixed 0.0dB volume setting without any preamp. Better to use a sensible output voltage from the Bartok and be prepared to use the volume control as intended.
Yes some do say that the best sound is with the volume control at 0.0dB but reality of this hobby is that it is always involves compromises when reality enters the picture. My compromise in this respect is to set my DAC to 2V with volume at 0.0dB but to use a preamp.
With no preamp and with these speakers 0.2v is too low. 2V will mean you selecting low volume settings in practice ( -25dB) as you have found. I suggest not setting the volume control at 0.0dB and relying on the possibility that the recording has been mastered at a suitable level but try 0.6V and use the volume control. Do compare this with 2V and using greater volume attenuation and see if you find a preference.
Thanks for your detailed response. I see you are very familiar with the ATC.
The essence of my question is what range of attenuation in the digital domain will be no worse than an additional component in the system, such as preamp (+ cables).
As far as I know, a high level of digital attenuation is undesirable, so I suggested that using 0.2v, I can use digital attenuation minimally, with minimal impact on the original signal.
I have ATC’s SCA2 preamp with which I can use Bartok at 2v in bypass. But I want to try to simplify the configuration and get a refund of some funds
I think that my ATC have 1v, this is a model with a amp-pack MK4 and a SEAS tweeter. Also, they have 2 trimmers. This is bass boost and gain. If I’m not mistaken, from standard 1v to 2v…
You have the SCM50ASL Pro version which does indeed have variable input sensitivity over the range that you quote. The SEAS tweeter means it was made between 2001 and 2017 ( I think).
I don’t think that is easily answerable as the range of permutations ( what preamp, what cables?) is huge and unpredictable. Further “worse” is in this context is ultimately subjective. What is worse to you may be better to me. As I said, try 0.6V line out with a small range of attenuation compared to 2V line output using a wider range. Only you can decide which you think sounds preferable to you.
…otherwise you would be in big troubles unless there are some hifi shop on Mars 
) the result could still be ear damaging.