adm95. I think I made a broadly negative comment about passive preamps above, However that was not really aimed at transformer types. I remember Max showing me an early Allegri and I was impressed so I am imagining that yours is pretty special. However I must stop thinking along such lines as I have already spent more than enough this year 
I love this discussion. Thought I would throw my two cents in here. I use a passive pre in my headphone rack because, even with my MSBâs two sets of balanced outputs, and pass-through loops on a couple of my headphone amps, I canât quite get enough signals to all the amps to avoiding swapping cables. So, I went in search of a good âswitching box,â precisely because I did not want any active preamp to add its additional (however âpositiveâ) coloration to the sound. Plus, remember that almost every headphone amp is actually an integrated amp already containing a preamp in the form of its volume and (sometimes) other controls. I owned a Tortuga LDR passive ore at one time, but embarrassingly could not locate it in my house. My wife thinks it may have gotten lost in our last move. I looked at the Allegri, but like many passives, it lacked sufficient outputs. But that got me going down the path. I looked at Bespoke, and may still go there, but I eventually found an interesting alternative in Poland: Hattor Audio, made by Arek Kallas, who some know for his lesser-priced stuff branded Khozmo Acoustic (a bit surprisingly favorably reviewed by 6 Moons). All I wanted was something to âstay out of the wayâ of the superb MSB DAC preamp (think Vivaldi, but probably a bit better), while affording me good switching controls for up to 5 balanced outputs. And wow, Arek did a superb job. I wish he was more on the map. Heâs gotten a few good reviews, but he deserves more attention. Anyway, thatâs been a very successful experiment/outcome for the headphone rack.
But for the speaker system, I have no such requirement. One input [maybe 2], one output. When it was primarily an all-PS Audio system, I had the BHK Preamp driving the BHK 300 monoblocks. Combined with the DirectStream DAC, it was quite musical and very pleasant. I would occasionally remove the preamp, but I always reinserted it. Something about the DirectStream just didnât have the âoomph.â But since the arrival of the Vivaldi, I made two changes: I removed the preamp and swapped out the BHKs for their predecessor Merrill Veritas. And wow, does that combo sing! I suspect the primary reason is the Vivaldi running at 6V. It definitely has more oomph than at 2V. And, I am able to do that while keeping the Vivaldi volume control within the range of -12 to -5db. Thatâs because there is actually already an active preamp in the system; itâs the custom Wavelet controller that is part of the Legacy Aeris speaker system. The Waveletâs sensitivity can be tuned by as much as -21db, while maintaining its ideal âsignal volumeâ setting of 85db. [I realize these are all relative numbers, but itâs how their system works, and I perceive this falls into the category of what Matej Isak calls âgain matching.â] Keeping the Waveletâwhich is actually a DAC (Iâve tried it, and itâs not bad), preamp, and DSPâat its setting of 85db helps produce the most accurate room corrections through the Bohmer room correction system. We throw the word âsynergyâ around a lot, but this combination really has it. I am waiting on the Merrill Audio Element 116 to replace the Veritas, and at that point, I think this will be, at least for a while, a I will not call it âend gameâ system I can relax and enjoy for some time to come. 
My dealer wants me to try an Ayre in the system. I will, but itâs with a jaundiced eye toward any (additional) active preamp. I just canât help myself, especially when I consider that I already have an amazingly over-active preamp in the speaker system. I might also explore the TotalDAC driver in both the headphone and speaker systems. Just for fun. I have owned very fine TotalDAC equipment before, but as I look at the specs of the d1, I have a difficult time seeing why or how its gain capability will make a big difference. Driving the Vivaldi at 6V is very satisfying. Vincent is a great guy to work with, so I plan to reach out to him and inquire. And I have inquiries into MFA and Townshend.
@adm95 I noticed the Allegri+ doesnât have XLR inputs or outputs. Do you know if the Allegri Reference would be a better option due to itâs XLR balanced inputs and outputs?
I would seek advice from Townsend themselves on this point. However, I would not assume that XLR is necessarily better in your application. I do know that they have suitable interconnects (xlr to RCA) for what you are asking.
If you need XLR, it is. 
but for clarity, I believe the Reference circuitry is actually single-ended throughout. The XLR connections are a convenience, not a sonic feature. FWIW, I ordered a Reference from Townshend just last week. Nice folks. A new review came out on it in The Ear this week.
Yes Greg, that is right. Max describes the Reference as " pseudo balanced" which reflects only the wiring of the receptacles . To have a properly balanced in/out would require transformers which Max says he avoids due to the " degradation of sound", rather a contradictory observation considering that the Allegri Reference is a transformer type passive preamp.
So the Allegri Reference will not provide the full benefit of common mode rejection.
I wonder if someone from dCS would like to comment as their usual advice is not to use adaptors from the XLR output to a single ended input but to use the single ended output instead. I guess that it might be argued that the Allegri may be acting as an adaptor with XLR input especially if its output to amp is single ended. 
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Yes, Iâve noticed that as well, though I think I understand the desire to avoid additional transformers in the signal path. I am likely wrong about this, but that sounds like a slightly different problem from the autoformers used for attenuation. The proof will be in the listening. I have also arranged to join the Bespoke Audio demo tour here in the US, and should be able to audition their box in the next couple of months.
@PaleRider Greg, am I seeing the price of the Cybershaft OP21A clock correct? Looks like approx. US$7,000. Is that correct?
In your writeup you mention SRS (Stanford Research Systems). Did you ever compare the SRS FS725 or PERF10 to the Cybershaft OP21A? I realize that the SRS FS725 is 50 ohm only, but Iâve been told 50 ohms will work just as well.
Hey Brian, yes, your currency conversion calculator is working. Cybershaft also makes less expensive models though. The SRS Perf10 was on my short list (I like to buy local when I can), but I could not get some questions answered. And it nagged at me a little that it was almost 10 year-old tech (I know that can be a mistake). Combined with the rubidium-vs-OCXO considerations, I started leaning back toward the Mutec and the Cybershaft. [I darn sure wasnât going to go with the Abendrot, even if they do make a slick stand for the Vivaldi stack.] The new Mutec was not generally available in the US (the dealers I spoke with couldnât tell me when they would get it). So, even though one Vivaldi owner (on Audiogon, IIRC) referred to the Cybershaft as âunobtanium,â I decided to pursue the Cybershaft. It didnât hurt that the WBF âreviews,â including dCS owners, were uniformly positive and ranked the OP21A first consistently (but please take that data point with a kilo or two of salt). To my delight, Kenji Hasegawa was very engaging, thoroughly knowledgeable, and very generous with his time and knowledge.
Iâm using Black Cat Digit D-75 MkII myself (Chris Sommovigoâs latest venture, having difficulty keeping up with brand names), but of the inexpensive ones I havenât seen mentioned in this thread and recommend, also because itâs thin, light and flexible, is Mogami Gold. Most importantly, however, stay away from audiophile snake oil brands - digital cabling MUST adhere to impedance specification! And Iâm saying this as someone whoâs experimented with lots and heard cool stuff over the years that cleary did not adhere to specs, by unorthodox thinkers with great ears, all good fun, lots to learn, but best avoided if one is on a budget.
Greetings from Switzerland, David.
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@PaleRider @PAR
Greg / Pete - you guys are a fountain of great dCS information. Iâd like to return to the discussion of whether to use a preamp with a Rossini (could apply to the Bartok and Vivaldi).
Based on the discussion here it sounds like the main reason to use a preamp is to avoid the dCS gain control being lower than 0.0dB to avoid loss of bit depth resolution. I always thought the dCS volume control was unique in this regard of not compromising bit depth at low dB settings, but thatâs a different discussion thread
However in the spirit of âtrying it for myselfâ I got out my trusty Radio Shack sound level meter and experimented using the voltage settings of the Rossini. I first set the Rossini at .6V and the volume control at 0.0dB and measured the sound level reading. I then set the Rossini at 2V and adjusted the volume control to achieve the same sound level reading, which was -12dB on the Rossini volume control. I then set the Rossini at 6V and adjusted the volume control to match the sound level reading. This put the Rossini volume setting at -18.5dB. I now had the Rossini volume control settings to conduct an A/B/C test.
Surely at -18.5dB I should hear some loss of bit depth, but Iâm not sure I heard ample difference in the 3 settings to pass a blindfold test. Is my test flawed or are my ears past their prime? Iâm OK with the latter as it would save me lots of $$.
I have decent equipment - my Rossini is direct connected via XLRs to a Boulder 2060 amp running at 240 volts connected to Rockport Altair speakers.
Iâll take a leap of faith with others that state thereâs a sonic difference in dynamics when the volume control is lower than 0.0dB. If this is true, wouldnât it make sense to ask dCS to give us a few additional output volume settings so we can keep the volume control in the -5.0 to 0.0 dB range vs. introducing a preamp and interconnects?
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Hello everyone - I have done quite a few listening tests with and without a preamp. I am using a Constellation Stereo 1 power amp and Wilson DAW speakers so a pretty standard setup with dCS. If you speak with dCS engineers they are adamant that a preamp is not necessary and the very slight loss of resolution with their digital volume control is inaudible until it is turned well down (which corroborates what Brian found in his tests). dCS can show this mathematically. In my own listening tests I do hear a difference with and without a preamp, but I remain unconvinced that one is better than the other. There is a slight apparent loss of dynamics and âslamâ without a preamp. However, I personally find that initially this may be a problem but on longer listening I find there is a greater transparency and naturalness without a preamp. Providing the Rossini produces enough current to drive a power amp (which it does no problem) then the preamp can only be acting as an active âtone controlâ. In the end I guess it all depends on your personal preference and the amount of money you want to spend on additional electronics, cables, power supplies, features, etc.
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As I think I wrote in one of the threads here, I have never heard any sound quality loss when reducing the dCS volume control setting from 0.0dB with direct connection. Others say that they do and that is their prerogative. However it may in fact reflect the input section of their power amps when given a lower voltage rather than the output of the DAC per se of course.
As for the question of preamps I have three choices of them here and all have been compared on numerous occasions to direct connection. I have always admired the clarity of direct connection. However technical perfection is not my objective. It is artistic satisfaction. For me that has come from the use of a preamp with all three generations of dCS stacks that I have owned.
However that relies upon my personal judgement of what sounds the closest to the sound that I am likely to hear from an orchestra live in a concert hall. That is my criterion and may well not be yours. Just to mix things up a bit I can prefer direct connection when playing well recorded rock music. Then the âslamâ that people like ( which is not what I hear live from the double bass section of an orchestra) can sound appropriate. However playing rock music is, for me, a tiny fraction of what I listen to. So, in my case, the technically less accurate but aesthetically preferable sound of my tube preamp is my overall choice.
This is not any sort of recommendation. We all seem to walk around with some kind of unique sonic ideal in our head. So equipment choice is ultimately subjective and may encompass all sorts of different ways to skin the cat.
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Brian, so glad you posted; I havenât heard the phrase âtrusty Radio Shackâ in a long time. Thanks for sharing your experimental results; they make sense to me. And FWIW, I was amazed by the quality of dCSâs digital volume control, Still one cannot help but wonder in oneâs head: am I hearing everything? For me, the short answer to your question is âwhat Pete and David said.â I think both are spot on, especially Peteâs last paragraph. In my case, it probably originated at a young time in my life when I was hearing a lot of live music in both large and small venues, rock and classical. Shortly before I went to work at a local stereo store, I was visiting friends and decided to check out their local audio [real audio] store. And thatâs where I heard my first Quads being driven by tube amps almost 50 years ago, I would eventually have the pleasure of hearing and even selling massive Infinity systems, but nothing would ever take the place of the magic in my head. But when I feel it again, wow.
We all have different pre/amplification equipment. I have experimented in my system with both the PS Audio BHK 300 monoblocks and the Merrill Audio Veritas monoblocks. I have tried the Vivaldi stack with and without the BHK preamp. I have settled for now on a direct connection between the Vivaldi DAC and the Veritas. The Veritas will soon be replaced by the Merrill Element 116 monoblocks. I have a Townshend Allegri Reference passive pre on its way here. It will certainly address the issue of bit depth loss, if any. For me, my system sounds âbetterâ without the BHK preamp; but before Vivaldi DAC, I had the PS Audio DirectStream DAC in the speaker system, and it was decidedly better with the preamp. Now, though, I do a lot of low level listening, using only the Vivaldi DACâs volume control, and my system sounds superb. For critical listening, I turn it up. So, it will be interesting to see how the Allegri affects my perception of my SQ, especially at low levels with the Vivaldi set at 0, and the pre doing the attenuation. Purely from an engineering point of view, I have a difficult time understanding why the insertion of any device, active or passive, should make qualities like detail, soundstage, and imaging appear different. And yet, better ears than mine say they do.
I guess, when pursuing that magical sonic image in oneâs head, you just have to be true to yourself. There actually are synergies in systems. and whether they appeal to each of us is entirely up to us.
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Thanks for all your replies. David summed it up perfectly, the sound may be different if a preamp is used, not necessarily better, but different. I used to own an AR Ref10 preamp and to me it sounded a bit more colored and less tranparent. But thatâs the magic of our hobby, we all get choices.
Thanks,
Brian âŚ
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Iâve used a dCS Upsampler/DAC combo without preamp for years, and tried a number of configurations, and heard many more at other peoplesâ homes, and come to the conclusion that itâs a matter of matching the DAC with the right power amp. Iâm back to Spectral amplification, with preamp. There are combinations, possibly because of the impedance matching, or because in this case, the amps are megahertz bandwidth designs, that inherently donât quite work. Itâs not the end of the world, done it, been there, but no, I wouldnât recommend it. The point is: itâs not a recommendation in favor of using a dCS DAC with or without preamp. Itâs a recommendation against using a Spectral power amp without preamp. Oh, and do I hear what the volume control does. Unfortunately, yes, I do. Itâs still the best digital volume control Iâve heard, and then, thereâs the realization that if one turns the volume way down, one canât hear what one canât hear anyhow, so what matters, does it affect what to me (and others in the house, e.g. late at night), is a comfortable volume level?
Greetings from Switzerland, David.
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And then thereâs my pet peeve, going back to when I designed loudspeakers: volume matching. Without it, weâre judging by feel, which may be all right to decide whatâs preferable in oneâs home system, but itâs insufficient coming (jumping) to conclusions on e.g. the quality of a componentâs volume control.
Greetings from Switzerland, David.
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I definitely agree David that the question of DAC-as-volume control is as much about the amp as it is about the DAC. And I also agree that low level listening, especially of a wide dynamic range recording, means one will lose some detail, regardless of the quality of the volume control.
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Thatâs one aspect where Vivaldi excels compared to earlier generation dCS Iâve owned (still own): listening at low levels. I tend not to be adamant about the superiority of one brand over another, but if I had to list any, this to me is one of its strong points.
Greetings from Switzerland, David.
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Indeed - the Fletcher - Munson curves mandate that your hearing frequency sensitivity varies with listening level so without âcorrectionâ such as a loudness switch it is inevitable ( and correct from a fidelity viewpoint ) that you will not hear the same content in the same relationship as the volume level is reduced.
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