Bartok as a preamplifier

dCS Products
21

Superb info. Thank you James.

This says it all for me. I was about to push the button on a long-winded explanation of why I find it handy to have the Townshend in my signal path after the Vivaldi DAC. The reality is that the majority of my listening is low level, and I find it advantageous to keep the Vivaldi at 0, and have the Townshend handle volume attenuation in the analog domain as transparently as possible subject to Jame’s points about cumulative electric circuits in the signal path. I find the AVC approach to volume attenuation the most pleasing for me.

6V is all about driving the DAC at its highest performance level. That’s all. Erno and Pete addressed that before and better than me. And James as well. The Townshend doesn’t seem to care, and the Wavelet is easy to adjust for the output. On your second question, the functionality of the two are so different that to me it doesn’t seem like a “choice,” but the answer to the question is easy: the Clock, hands down. The passive pre is simply an attenuator that I find useful for low level listening [which is the majority of my listening]. As James so succinctly describes, the pre cannot create more information, but if the system sounds “better” to the listener that owns the wallet, then it means it is changing the sound information from the state in which it was received from the DAC in a way the listener finds gratifying. I enjoyed the glowing reviews of the TAR, and I prefer it in my system over the Bespoke and the Ayre I tried, but that is because it seemed to change the sound the least. My first reported listening impressions were purely subjective as compared to the Bespoke [wider soundstage, better micro-detail, etc.]; I don’t know if a direct comparison would again produce the same reactions, but I am long past caring. I don’t have other preamps available to me right now other than the PS Audio BHK, but I already know that I no longer find its presentation pleasing. With the Townshend, I now have the conveniences of the BHK and Ayre, done better than the Bespoke, with the least amount of alteration [“reduction in transparency” to borrow James’ terminology] in the Vivaldi DAC’s information that I can discern. That’s what I wanted. If I could play my system at what I think of as normal listening volumes all the time, I would not need/want the Townshend. I would have the DAC feed directly into the Legacy Wavelet.

The Clock, though, truly improves the informational completeness of the sound. If you want the best out of the Vivaldi DAC, in my view, the Vivaldi Clock is required. After that, it’s about convenience and psychoacoustics.

3 Likes
22

Excellent news: I can spend my money on a dCS clock :smiley:. Unless I would prefer the distortion of a preamp :thinking:

Fantastic information James thank you. Just what I was looking for.

The only question that remains in my mind is whether the SNR is noticeably reduced for a lesser output V level than a 6V output level given that the DAC noise floor is fixed. Vivaldi “Residual Noise Better than -113dB0 @ 20Hz-20kHz unweighted (6V Setting)”. Are you able to reveal the residual noise at other output V settings? I suppose the question is if the preamp added less noise than the lower DAC output V introduced then a preamp could theoretically increase the SNR IF you would otherwise have to use 0.2V or 0.6V output setting. I doubt it but would be interested to know.

How about introducing an enhanced volume control that automatically changes the output V as you increase volume demand much like an automatic gearbox in a car. So it starts at -80dB digital attenuation at 0.2V output and as you increase the volume setting to 0dB digital attenuation it automatically changes the output to 0.6V and simultaneously drops the digital attenuation to -10dB (or whatever it needs) and so on up to 6V so that it maintains a smooth response and best possible SNR at all times. There would of course be a min a max setting option somewhere much like roon offers.

Did I take that too far? :zipper_mouth_face:

Thank you for the advice Greg.

2 Likes
23

Thank you, James. Like Greg, I usually listen through speakers at low level (neighbours issue). When driving my power amp directly, I ended up around -50dB setting at 2V out. No gain issue in my system. The result at this low level was not pleasing. Adding a preamp is.

3 Likes
24

Thank you James, you have provided serious food for thought :slight_smile:

25

Also, thank you all for sharing your personal experiences and thoughts on this matter :+1:

26

@James would you advise going down to 0.2V line level output to allow lower volume?

Like @Ermos I need to attenuate significantly, in my case when I am listening late at night in the room below bedrooms

If I remove the preamp and go direct from Bartok to my ATC actives, what are your recommendations for addressing the gain issue?

Thanks

27

How should we react to the two articles below that express opinions of dCS volume controls? Are they mistaken? I do not hear what they seem to.


Last paragraph: " However I also tried the Bartók volume control and would not for myself accept the sacrifice in sound quality: it significantly affected clarity, timing, image depth, micro detail and subjective dynamics, so I would leave it at one of the several fixed levels and use a top class external control instead."
“Running off a top-pedigree dCS source, Angel demonstrated how the slightest engagement of its volume control—which we can assume was executed to a very high level—was immediately obvious as a filtering effect. It sounded like an opacity command by contrast to his own analog controller.”
28

Just my personal opinion, 6moons is full of subjective opinions that very often has no real basis in fact. Only to be read if one wishes to indulge in mindless entertainment :wink:

2 Likes
29

I was influenced by the HFC article to try a preamp between the Bartok and ATC actives

Whether due to euphonic distortion or lack of digital attenuation, I do prefer it with the recently added preamp

But James’ post has now prompted me to A-B test … one for a snowy lockdown Sunday :notes: :cold_face:

2 Likes
30

The 0.2V and 0.6V output settings were added as a reaction to modern streaming technologies – AirPlay connecting to your system, whacking the volume up to full and blowing some drivers for example is not fun. Lower output voltages are a useful safeguard against such things. I once serviced a speaker which spat a voice coil across the room because of a smartphone jumping from being connected to the user’s car to their streamer via Bluetooth – by all accounts it gave the cat a hell of a jump.

With that said, to my knowledge in the event of night-time listening where a lower volume is required, the benefit of using a lower output voltage setting and keeping the volume control towards the top end of the range is that with a lower output voltage and higher volume control for quiet listening you keep the signal to noise ratio in the Ring DAC itself higher, as the volume control stage immediately precedes the FPGA’s output to the Ring DAC whereas the output voltage setting takes place after the D/A conversion. The signal to noise in the analogue output stage will still be lower whether using a lower output voltage or a higher voltage but lower volume control, but the conversion stage retains a higher ratio with a lower output voltage in this case. My advice would be to use whatever output voltage setting that allows for higher range usage of the volume control – though I will double check this point on Monday.

Talking about the volume control implementation used in dCS DACs, given the fact that the volume control is simply the last step in what could easily be a very long stage of digital filtering, if working at a lower volume control meant the maths behind this processing was in some way flawed and could create a loss of dynamics in itself, the effects of digital filtering would be pretty horrendous. This definitely isn’t the case when done correctly. The argument is therefore not whether a digital volume control is the correct way vs analogue, to my mind the conversation is actually around whether volume control pre-D/A conversion or post using one of a variety of methods is most appropriate. That becomes incredibly tricky to draw anything meaningful from, because the art of product design is being aware of the trade-offs with different approaches and striking a good balance between the competing compromises. It is possible to get good results with either, and I have no doubt every approach has been considered over the decades with a dCS product. From conversations with our engineers on these topics, honestly the sheer number of angles that are considered when designing each stage of a dCS DAC are genuinely staggering.

I will say that as is the case with every area of dCS products I have ever thoroughly investigated, the system as a whole and end user experience as a whole has been taken into consideration. We aren’t in the game to make products which will win at spec sheet comparisons, we are out to make ones that are at the forefront of what is possible for sound quality. For example, if digital purity was the name of the game, even at the expense of the “end product”, one could simply connect the DAC outputs to the output jacks of the product and let whatever is on the other end of it deal with load matching and such. Adding a line output stage to the DAC will add in the “downsides” an analogue stage will naturally bring (distortion, noise etc.), but will likely allow cables and (unknown) input stages down the chain to be driven much better than would be possible simply by connecting the DAC output directly. This is what, from a spec sheet, would be seen as a compromise in the unit design – but it is one that in the real world results in an improvement in system performance.

I appreciate this may not be a popular opinion in some areas of the internet, but any opportunity for blind testing should be taken where possible when A/B comparing kit. If sound quality is king to you, let your ears be the judge, not the parts of all our brains that are predisposed to want us to think a certain way about a piece of equipment. If that test concludes you prefer the preamp in the system, more power to you (I‘m sure there is a bad pun in there somewhere)!

8 Likes
31

The verdict :grin: Then you are stupid.

I did several not just A/B, but A/B/X comparisons. Let us say: just my bad taste, or psychoaccoustics, or …?

Adding a line output stage to the DAC will add in the “downsides” an analogue stage will naturally bring (distortion, noise etc.), but will likely allow cables and (unknown) input stages down the chain to be driven much better than would be possible simply by connecting the DAC output directly. This is what, from a spec sheet, would be seen as a compromise in the unit design – but it is one that in the real world results in an improvement in system performance.

That is why I asked this community if someone is interested in a separate dCS preamp. It might break your philosophy, on the other hand it might open a practical choice.

32

:rofl:I think most of us are in this for pleasure. If you enjoy it more routed through an old amp with the bass and treble turned up and the loudness on then why not?

Of course dCS cannot voice the dac to try to make a particular group happy. They have to make it as close to the recording as possible. It’s up to the individual to alter that to whatever they enjoy if they wish.

3 Likes
33

James, thank you for this superb explanation. I am in fact going to spend some time comparing (the extended type, over time, not blind quick-switching) the Townshend with direct output at lower voltage. I won’t be surprised if I learn something new. But it might not change my listening much, because one of the reasons for the Townshend is its easier-to-use, unobtrusive remote. Hmmm, but maybe Mosaic for both voltage and volume control . . … Such wonderful choices we have.

I never thought this was about “breaking philosophy,” so much as it is not what they do. There are hundreds of high-end preamps that, almost by definition, are about individual taste. The DAC, however, is agnostic to all of them. Why step into an inherently lower market share outside their principal expertise?

34

Not just 6moons. Much of the industry/review press, even some of the forums like Head-Fi and WBF, is little more than hyperventilating tabloidism. The amount of advertising on those pages tells you everything you need to know. They are marketing and selling our wallets to the advertisers. Objectivity is a bit low-octane for that purpose.

1 Like
35

FWIW HFC carries no advertising so in that article Colloms and Todes may be less influenced by revenue; they are still of course only two opinions

36

Andy, I liked the Colloms piece as well, and other HFC work, and while I am not looking to pick a fight, it’s naive to think they are not affected by industry relations. They are affiliated with many others that do accept advertising. For example, Colloms’ reviews appear in Enjoy The Music, which accepts advertising, and HFC appears on ETM’s web site as an affiliate along with many others. It’s unlikely MC’s extensive reviews are uncompensated. Perhaps they are, but I hope you’ll forgive my circumspection.

P.S. I also think MC is over-infatuated with the Bespoke, which has caused me to be a little more wary of his enthusiasm. I demoed more than one passive pre in my home, including the Bespoke graciously arranged by Harry Sullivan. It was very nice, but to my ears, not the best or most convenient, and I didn’t buy it. To each their own. I also thoroughly enjoyed the Rafael Todes and Jason Kennedy reviews—both of which appear in advertising-supported publications—of the Allegri Reference, but some of the effusive “makes the music sound even better” has to be taken with a grain of salt. I think the Reference is superb. I like the technology it uses and the theory of its design. But its purpose was to add convenience to my system while doing the least damage possible to the music. I don’t think it makes the music sound “better” than straight out of the Vivaldi.

1 Like
37

I’m no defender of those two authors or their opinions, of course the pieces are compensated, we all have to make a living :grin:

If they were affected by industry relations with dCS I’m ok with that; it led me to a demo, purchase and happy place :laughing:

1 Like
38

I can’t argue with that :wink:… That said, some, like 6moons, PFO etc., tend to veer more towards mumbo-jumbo explanations than others like Stereophile.

You’re also right about HFC, although their biases are not as apparent, once you scratch the surface, it becomes a little clearer that their allegiance is with the manufacturer community, rather than the paying subscribers; after my recent direct interactions with MC about their Ethernet cable/switch review, it became apparent that MC is more interested in staying on the good side of some very questionable Ethernet Cable/Switch manufacturers than providing their readers with actual science. Pity. :pensive:

3 Likes
39

Agreed. When I first encountered 6moons, I rather enjoyed the unorthodoxy. After a while, it became tiresome.

1 Like
40

Great. Look forward to hearing if SNR varies by output voltage. And if it would even be audible.

Regarding those articles I wondered if they were referring to an older DCS design that maybe didn’t do volume attenuation so well but 7 years would be current Vivaldi I guess. Or a more revealing speaker than mine might reveal what I currently do not hear.

For no good reason I’m pretty sceptical of most UK hifi publications but less so about Stereophile. As a bigger operation I hope they would be less susceptible to review massaging. But who knows.

1 Like