@georgehifi : yeah; I am not at all mechanically minded, so what you you offer is, indeed, "sound advice"! Thanks for the pic.
DACs and bass response?
I'm auditioning dacs in my system. One (COS) was way to analytical, overall, but had very tight bass. Another (Aqua La Voce) is what some would describe as "musical" and sounds terrific in all aspects except bass. My cdp alone does better in that regard. I have monitors and no subs. Can I expect that dacs that are hyper-detailed will also offer tighter bass as a rule?
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In general I found that there is a trade of between mid/high to low dynamics and not only in Dacs, gear that sounds very detailed and 'sweet' (strong at mid and high) doesn't peoduce strong punchy bass and in contrary gear that has accurate and tight bass tends to be less detailed and musical at the mid/high section. In general I prefer to sacrifice a little bit at high/ mid to achieve strong and tight bass . |
Shadorne - I think the problem lies in where jitter is measured. Most manufacturers measure it at the oscillator or even use the spec sheet oscillator number. What I'm talking about is measuring the jitter of S/PDIF signal as it arrives at the DAC. I have never seen direct measurements of this, except what I published. Companies that make Transports, converters, reclockers and servers all need to measure this directly, but they don't. They don't need to clip probes onto chips to do this. They need a 75 ohm termination inside the scope or AP equipment. Measuring jitter inside the DAC, say on a I2S bus from a USB or Ethernet converter makes a lot of sense, but it requires measuring both the bit clock and the Master Clock. The D/A can use both of these or either one to affect jitter. I doubt if this is done in this J-test. Steve N. Empirical Audio |
Since you are clearly able to build a device that takes 800 psec jitter from an Oppo and turn that into 20 psec jitter with your Synchro-Mesh, then why do you believe that nobody else has a DAC that can correct incoming jitter to completely inaudible levels - around 20 psec or less? Good question. The answer comes from 10 years of modding equipment, seeing the circuit boards exposed in these DACs and hearing them at shows. I don't see the things implemented in DACs that are required to achieve these low jitter numbers. It's not just selecting a low phase noise oscillator, or providing a dedicated power supply for it. It goes WAY beyond that. It has taken me 10 years of modding and tweaking on my own products to learn these tricks. And I don't hear the SQ that would result in exhibit rooms at shows if they had implemented these optimally. After I retire in a few years, I may write a technical book so that other designers can benefit. I have thought about teaching a course at a college, but I live in the sticks. For now, these are trade secrets that differentiate my products. Steve N. Empirical Audio |
In general I found that there is a trade of between mid/high to low dynamics and not only in Dacs, gear that sounds very detailed and ’sweet’ (strong at mid and high) doesn’t peoduce strong punchy bass and in contrary gear that has accurate and tight bass tends to be less detailed and musical at the mid/high section. This is not inherent in components, it is a function of the design. This has everything to do with 2-3 things: 1) values and placement of decoupling caps 2) types of decoupling caps, ie; Teflon, Polystyrene, paper-oil 3) jitter If proper attention is paid to 1 and 2, you can usually have your cake and eat it too. My 10 years of modding has taught me that many designers don’t understand power delivery, so they pick capacitors just like other manufacturers pick, or what it recommends in the data book of the integrated circuits. Many of the guidelines in data books are only to make sure the circuit functions, nothing to make sure it delivers great audio quality. The errors just get repeated over and over. This is a bit of a black art I have to admit. Tube equipment is a case in point. Many audiophiles avoid tube equipment because of a "tubey" sound. This is generally due to 2 things: poor choice of tubes and non-existent decoupling caps, particularly for high-frequencies. Designers somehow think that because of the high voltages and low currents involved that these are unnecessary. If they are optimally chosen and placed along with selecting good tubes, it can sound almost identical to SS. Steve N. Empirical Audio |
@audioengr The J-test does not use probes. I am surprised you are not much more familiar with the J-test, as it is an industry standard jitter test (used by Stereohile and others) and since everything related to jitter appears to be your specialization expertise. See this link http://www.nanophon.com/audio/diagnose.pdf The J-test uses a known digital signal and analyzes the spectrum of the analog final output of the DAC for spurious frequencies that should not be there. It is actually a complete approach to testing the entire audio chain from digital signal passed through any cable into the digital input of the DAC and a detailed examination of the final analog output. Any jitter at all anywhere that reaches the D to A chip will result in quite obvious spurious analog signals that do not match the known input. Any source jitter, cable jitter, interface jitter, LIM jitter and intrinsic jitter (in fact the sum of all and any jitter) is tested for. |
Why would someone buy a tube component that almost sound identical to Solid State? Because Tubes are usually lacking in dynamics, bass tightness or HF extension. You can get the liquid midrange of tubes and the dynamics, bass and HF extension of the very best SS without having that "tubey" distorted sound. Steve N. Empirical Audio |
The J-test uses a known digital signal and analyzes the spectrum of the analog final output of the DAC for spurious frequencies that should not be there. It is actually a complete approach to testing the entire audio chain from digital signal passed through any cable into the digital input of the DAC and a detailed examination of the final analog output. Any jitter at all anywhere that reaches the D to A chip will result in quite obvious spurious analog signals that do not match the known input. Any source jitter, cable jitter, interface jitter, LIM jitter and intrinsic jitter (in fact the sum of all and any jitter) is tested for. I don't believe the DAC output is a good indicator. It will change with every DAC you use in the test, so testing for instance a reclocker or a USB or Ethernet interface would be insufficient. What if the particular DAC used introduces spurious signals unrelated to the jitter of the incoming signal? It is a result of the DAC, not the USB converter driving the DAC for instance. I also don't like using a fixed signal. I would rather see actual music data. I have seen lots of J-test plots in Stereophile over the years. None of them seem to correlate well with sound quality. I think this direct digital measurement I am making is superior to the analog measurement for correlating to SQ. So far, its helping me make decisions on future products. Steve N. Empirical Audio |
@audioengr Hi Steve. I took a cursory look at the overdrive info on your website http://www.empiricalaudio.com/products/overdrive-dac and user manual. I couldn't find anything about the type/kind of D/A chip(s) or whether or not your technology is considered delta sigma, multibit r2r or something else. Please advise. Thank you. |
Steve wrote, “Because Tubes are usually lacking in dynamics, bass tightness or HF extension. You can get the liquid midrange of tubes and the dynamics, bass and HF extension of the very best SS without having that "tubey" distorted sound” I am sure you’re going to tell us if there is component out there that is capable of all of the above without the “tubey” distorted sound. |
Hi Steve. I took a cursory look at the overdrive info on your website http://www.empiricalaudio.com/products/overdrive-dac and user manual. I couldn't find anything about the type/kind of D/A chip(s) or whether or not your technology is considered delta sigma, multibit r2r or something else. Please advise. I decided to use a Analog Devices delta-sigma, but only because I can select the digital filters for it rather than it selecting the filter for me. I cannot seem to get the HF transient response from older ladder chips that I can from newer delta-sigma chips. It also supports 24/192 PCM, as well as allowing for reference voltage-based volume control. I previously offered a tube DAC design using a ladder chip called the "Spoiler". It was very musical, but ultimately did not deliver on the accurate HF sonics that I'm after. It also required hard-to-get expensive NOS tubes to sound really good. The only other option is to design a ladder DAC from scratch or in an FPGA. I don't have the bandwidth for that unfortunately. BTW, audiostream will be reviewing my new SX DAC soon. Steve N. Empirical Audio |
I am sure you’re going to tell us if there is component out there that is capable of all of the above without the “tubey” distorted sound. There are a few. My own customized SET monoblocks fall into this category. Others are: Nagra VPA Any Wavac Prima Luna Arte Forma Due Volte - I have the customized version of this one I prefer SET amps, but the Prima Luna sounds really good at shows, and they use quality parts in them. I always enjoy their room. Steve N. Empirical Audio |
Here is basically my setup, but this one was used at a show, so its not my amps or speakers. I have my own custom versions of both. http://www.arteformaaudio.com.tw/due-volte.asp The Vapor picture at the bottom. Steve N. Empirical Audio |
It’s hard to believe that a DAC designer wouldn’t use effective caps in their design. Before changing out caps, why not try a signal re-clocker and a high end fuse and maybe, up sampling? I’m not trying to over simplify this but most audio enthusiasts lack the ability to evaluate equipment via scientific measures. Some may have higher standards but I’ve always trusted my ears. |
@audioengr Oh yes I absolutely agree that the J-test is not diagnostic. If there are spuriae then it is unknown where the jitter came from. All it says is that the DAC failed to produce the digital test signal properly - it could be jitter or it coyld intermodulation distortion or both. However, if a device passes the J-test with perfect results then one can only conclude that all distortion spuriae including any jitter of any sort are all below the noise floor. Devices that pass this test perfectly are indeed rare which is why I agree that most DACs need a reclocker. |
Stuartk - I haven't seen any references to Bel Canto here so I'll put in my 2 cents worth since I just upgraded from a 1.5 w/ LNS1 to 3.75 w/ VBS Bel Canto DAC and everything including the bass is clean and tight through all the instruments. Although you can use the Bel Canto DAC to replace the Pre-Amp also, I still use it as DAC only. And for the techno and sales boys, the jitter is 70 femtosecs (fs ) ( aka .07 picosecs (ps ) ) ! FYI - My 1.5 Bel Canto was 2 psec on the jitter scale. The interconnects DO make an overall sound dif also, but I think you should lend an ear to a Bel Canto 1.5 or higher and put the excess monies saved in other upgrades you might want. Happy listening ... |
I ordered La Voce yesterday. This is my first DAC, so I’m no doubt a good deal less sophisticated than many who’ve posted on this thread in my capacity to assess this type of component, but it seems to do a good job occupying a middle ground. It’s not what I would consider overly analytic but provides a much detail as I want to hear. At the same time, it’s what I would call "musical" (a term reviled by some, but each to his/her own) without straying into what I would regard as tube-like euphonics. PRaT is very important to me and La Dolce serves up a generous helping. The other two DACs I auditioned were, by contrast, to my ears, in my system, quite extreme. The COS was unnaturally detailed while the Metrum’s cholesterol count was off the scale. In the end, hearing presentations at these extreme ends of the scale proved useful in evaluating the Aqua. BTW, I found Alex at Alma Music and Audio in San Diego (the sole CA Aqua dealer) to be terrific. I hope this doesn’t violate any thread rules. Thanks to all who offered suggestions and warm wishes for a happy holiday season! |
That Arte Forma SET amplifier seems like a very high tier no nonsense effort. No doubt that it is exceptionally honest, open, transparent and natural in its sonic character. I suspect it is quite capable of revealing the fine nuances of the various upstream DACs and sources. The nice thing about it is that it is DC-coupled, so no caps in the signal path. Also, the version they sell now contains a circuit-board. The one I have was a point-to-point wired prototype that I further modded. It's too bad they don't offer the wired one, but they could not seem to get consistency in the build. I don't use any of their tubes BTW. Steve N. Empirical Audio |
However, if a device passes the J-test with perfect results then one can only conclude that all distortion spuriae including any jitter of any sort are all below the noise floor. This assumes that the DAC has excellent HF response and transient response. If it doesn't, the spuriae will be masked, filtered. Take the same source to another DAC that has better HF and transient response and you might see more spuriae. I think it depends on the DAC, which it should not. DAC analog circuits should not be part of the measurement IMO. Steve N. Empirical Audio |
It’s hard to believe that a DAC designer wouldn’t use effective caps in their design. It is, but I would not have had a lucrative modding business for 10 years if it was not the case. I trust my ears also. I have to because measurements just don't cut it IME. A good audio designer must rely on both measurements and their ears. I cringe when I read about someone starting out in this industry and thinks they can navigate on measurements alone. I recently read this on DIY forum... Steve N. Empirical Audio |
stuartk DACs and bass response? Aqua La Voce The Aqua La Voce uses the R2R Multibit PCM1704, a killer D/A converter especially in the bass. Used by Naim555, LinnCD12, ML39 ect all which have killer bass. The La Voce I/V stage after the 1704 should be fine and the output buffers should be fine, all that is left is the cheap blue coupling Cap. As I pictured before, or even better go direct coupled. Cheers George |
@charles1dad: I tried swapping out the digital cable, then the power cable. At first, I thought they were both contributing to the improved bass. After posting the above message, I listened further and and determined that the replacement power cord was actually rolling off highs, resulting in an overall "darker" tonality. It was also diminishing the overall sense of organization. The latter may not be an audiophile term. What I mean is that, with the replacement power cord, simultaneously overdubbed guitar parts, for example did not sound as if they were properly synced. Instead, there was a sense of chaos. Replacing the original power cord yield a sound I preferred. Nevertheless, I’m going to try still another digital cable. as this is my first DAC, I have no previous experience with digital cables and it seems prudent to explore a little further. |
Here is what I determined by designing and building many digital cables, and making measurements on those and others: 1) the 75 ohm impedance of the cable is critical and should be uniform over it's length 2) Termination of the 75 ohm cable to RCA plugs is a non-starter. Must be terminated to a proper 75 ohm connector, and a good one, like RF or BNC. 3) Use of pure silver in the 75 ohm cable is preferred, much better tonality. 4) 100% shield is beneficial 5) Conductor gauge is critical. Should be 26 Gauge or smaller to avoid skin-effect Here are a few measurements: http://www.audiocircle.com/index.php?topic=154425.0 Steve N.Empirical Audio |
Here is what I determined by designing and building many digital cables, and making measurements on those and others: I went with a Belden 1694A cable with Canare RCAPs from Blue Jeans Cable. I'm pretty sure it meets the quoted criteria. https://www.bluejeanscable.com/pages/technicaldocs/canarercap.pdf |
@audioengr I appreciate the fact that at least you measured the 1694A and have data results handy. No doubt the results would be less than exactly perfect. I’ve also read - here on Agon - that the length itself (of any cable) can be critical in minimizing jitter. I’ve also read - here on Agon - to ignore measurements completely and simply rely on your own ears. You know as well as I do that this "hobby" is an endless pursuit of perfection, and after a certain point - when one already has a good sounding system with quality components - diminishing returns sets in rather quickly. In my opinion, and from my own pragmatic approach, right or wrong, changing cables produces only infinitesimally small changes. I believe changing cables (power, interconnects, whatever else) simply produces a difference and not a "better or worse" scenario (irrespective of measurement data). I use this cable to feed my Schiit Yggdrasil DAC. I am relying upon Belden’s and Schiit’s "claims" (published marketing BS as well as third party independent lab testing which in the case of Belden is ASTM D-4566) in addition to my own listening and derived enjoyment to arrive at the conclusions that (a) I’m not sacrificing any enjoyment by not having a better cable (or better anything for that matter) and (b) if I’m wrong and simply haven’t experienced the better enjoyment yet to realize I’m actually missing it then "Oh well, so be it". EDIT: And for what’s worth - and given the thread title - IMO the Bass from Yggy is phenomenal. And I've read quite a few posts from owners/others who report the same (in comparison to other DACs). |
gdhal, based on my experience, everything matters at varying degrees. When I recently replaced gold plated locking banana plugs with silver plugs on my 6 gauge speaker cables, the clarity and detail improved exponentially. The benefits to my recently added ISO Regen and LP1 proved beyond what I could have predicted. I really wasn't expecting a difference by changing my banana plugs from gold to silver. However, it seems as if dealers and distributors will tell us that what we need, are whatever cables they just happen to be selling. In other words, I believe it to be difficult for hobbyists to determine exactly what they want or need in their stereos, especially in an age where most consumers will make purchases via the internet rather than making comparisons in the dealers show room. As funny as it might seem, I recommend that audio enthusiasts read about aesthetics and music theory in order to find their solutions in equipment, tweaks or upgrades. After all, isn't this about musicality? Happy Holidays. |
@gdhl: With all due respect, the difference I heard in the bass presentation as a result of changing digital cables was not "infinitesimal". I was about to give up on La Voce and continue my search. Swapping out the cable changed my mind. I bought La Voce. My experiments with cables has been varied-- some indeed seem to be merely "different". In other cases, cables have provoked a strong appeal or strong distaste. @goofyfoot: I wish you luck in getting a majority of audiophiles to agree on a definition of "musicality"! ;o) As a guitar player, I'm familiar enough with music theory but I have to say it's never figured in any way into my gear selection. However, I'd love to hear more about the connection you perceive between the two. As for reading about aesthetics, isn't reading a |
I believe it to be difficult for hobbyists to determine exactly what they want or need in their stereos, especially in an age where most consumers will make purchases via the internet rather than making comparisons in the dealers show room. This is precisely why I’m doing these jitter measurements and trying to correlate them to sound quality. If a measurement can be proven to be useful, then no amount of snake-oil claims can compete with it. After all, marketing BS is what is mostly written about cables. Most cable manufacturers don’t put ANY measurements on their sites. I’m trying to improve that situation. gdhal - If I could significantly improve my system dynamics, imaging and clarity for $275, I would jump at this. Chump-change, besides it’s 30-day money-back. I recently got a IFI SPDIF iPurifier for my Home Theater. Another no-brainer. I lowers jitter for Dolby Digital and DTS for $150. Improves movies significantly. I can finally hear all of the quiet dialogue in the starting scene of "Gravity". The movie makes sense now. I prefer my Synchro-Mesh for 2-channel. Steve N. Empirical Audio |
stuartk, there's of course nothing definitive about the term musicality, it's subjective and ever changing but I do believe that having a certain amount of musical knowledge is an asset. I'd never advocate for, checking your brain in at the door. For me, harmonic theory and aesthetics act as a road map for what I want to hear and for what I am listening to. |
@goofyfoot / @stuartk / @audioengr I appreciate your encouragement and advice about the paths to improvement. At some point I suppose I’ll try new things (cables?, isolation platform?, not sure where) and presumably get closer to nirvana. I’m good for now though. FWIW, my next improvement attempt (which will happen in the coming days, not weeks or months) will be to use shorting caps on the inputs to lower my already very low noise floor. |
...but I do believe that having a certain amount of musical knowledge is an asset. @goofyfoot I agree. This is why soon after I obtained my Yggy I enlisted the help of my dear friend whose a professional musician (electric bass) and who has formal musical education. It didn't take him all but a few moments to direct me as to what to listen for to detect the sonic differences between my Oppo UDP205 and Yggy! That plus finding the proper source material made things ever so obvious. |
FWIW, my next improvement attempt (which will happen in the coming days, not weeks or months) will be to use shorting caps on the inputs to lower my already very low noise floor. This is a mod that will have little effect IME. Inputs that are not selected are not involved. Better off to figure out how to eliminate ground-loops. Now this will actually reduce the noise floor. I have zero ground-loops in my system. Jet black background. Steve N. Empirical Audio |
Why don’t you use an APX555 from Audio Precision? Triggering is automatic and programmed. It's a programmable scope with special jitter program. It does have some limitations of scaling the axis etc., but useful so far. The newer scopes don't have as many limitations, but they are way more expensive, like buying a house. This particular scope when new was $130K with the jitter software. I purchased it used. The active probes alone are $5K new each. The AP stuff is great for analog, but this is digital. Even the APX555 only has 1MHz bandwidth. Way too low for digital. Even the clock fundamental can be 49MHz. Edge-rates have GHz components. The Tek scope I'm using has 7GHz bandwidth. This is 7000 times higher than the AP. This is what is needed for accurate digital measurements. The newest version of what I have is the DPO70000, which lists for $315K and that is not including the jitter analysis software which will probably be $25K more. Steve N. Empirical Audio |
This is a mod that will have little effect IME. Inputs that are not selected are not involved. Better off to figure out how to eliminate ground-loops. Now this will actually reduce the noise floor. I have zero ground-loops in my system. Jet black background. "Little" effect is precisely what I anticipate. As to inputs that are not selected not being involved, I recently raised this "question" elsewhere on the forum in a related thread (like RCA plugs, shorting caps, etc.) and was advised that (paraphrasing) theoretically they *are* involved and that shorting them can only help, albeit however slightly. Moreover, there have been some folks on this forum who have reported positive results by shorting unused inputs. Further, I did some do diligence by checking with the manufacturers of my gear (Golden Ear and Musical Fidelity) and both state there is no harm in doing so, although also state there shouldn’t be a noticeable benefit. This is a low cost attempt ($20?) on my part anyway, so I shall see. Besides, I’m a big Joni Mitchell fan (a Grateful Dead head nevertheless). She so eloquently puts it (Amelia) People will tell you where they’ve gone They’ll tell you where to go But till you get there yourself you never really know Where some have found their paradise Others just come to harm Consider this my holiday musical gift to all: https://www.youtube.com/watch?v=1N7gPcCgkZU |
