 De verschil in de kwaliteit tussen de vreemde DAC en de meest perfecte DAC is enorm, waardoor je een hoge kwaliteit-playback-systeem gebruikt. Maar wat maakt de meest perfecte DAC de meest perfecte? Een digital to-analog converter heeft een job dat is makkelijk te beschrijven. Het heeft te renderen digitale samples in verantwoordelingen op precies intervallen. Maar dat is misschien een beetje abstract en soms een explicatie in orde. Let's imagine a short piece of analog music signal by chance being a straight line like this. On digitizing amplitude samples, techspeak for measuring the voltage, are taken at the given sampling frequency, like 44100 times for CD quality. These measurements are stored in a table and sent to a transport of storage medium like a hard disk, CD of thumb drive. On playback, the table is red and then rendered in discrete voltages. This would have resulted in a staircase pattern if not for the reconstruction filter that slows down this signal so the original straight line has regained, if all went well. If the interval at which the voltages are plotted is not very constant, there will be amplitude errors as can be clearly seen when a white line is plotted behind the resulting red line. If the jitter is caused by the interference of a single frequency, this creates side bends at the modulation frequency of the clock and leads to what is commonly called the digital sound. In layman's terms it will cause tones in the signal that originally weren't there. But there are several signals that can cause jitter, including noise. The jitter then is less easy to identify, but still ruining the sound quality. Sound is a variation of sound pressure over time. The sound pressure is converted during recording to voltages and then coded in digital information while the time factor is stored in the sampling frequency. The time factor can be distorted by jitter, but the amplitude of the voltages can be of too of course. We call this poor linearity. If the digital signal says the output voltage of a given sample should be 0.123 volts and the real output voltage is 0.156 volts, the converter is not linear. We measure this by applying digital signal levels to a DAC and measuring the output voltage. This is such a measurement. You see that minus 30 dB digital input generates a voltage that is 30 dB below the maximum output when you look at the turquoise line. The same goes for minus 40 dB, minus 50 dB en so on. The green line shows the deviation from the full linearity and you can see that this DAC is very linear down to minus 100 dB, with only minor deviations down to minus 120 dB. Minus 120 dB equals a resolution of 20 bits, which is about the best I have ever measured, regardless the price of the DAC. A real-world 24-bit DAC does not exist. DACs that claim to be 24-bit will accept 24-bit long digital signals, but the lower 4 bits will be irrelevant unless the digital filtering uses it for dithering and rounding off. The audibility of a DAC's non-linear behavior is questionable, at least in my experience. In de mid-80's we measured a lot of CD players, many of which didn't even manage to perform a 16-bit converters. But it was always jitter that was the main factor, although we didn't know back then that it was jitter. We learned that some years later. In the animation on how digital works, we have seen that without the reconstruction filter the output of DAC would be a staircase. I must admit that a staircase as in the animation is most unlikely since that would need analog electronics with unlimited bandwidth. It rather is a staircase-like signal. The reconstruction filter is a solution for this. It slows down the signal to a degree that is just fast enough to connect two samples in a natural way. But there is no such thing as a free lunch. Filters have not only influence on the amplitude, the wanted roll-off, but also on the time behavior. They have in many attempts to make the perfect reconstruction filter, but very good filters often are very expensive. Most often the digital signal is upsampled and filtered during upsampling, then sent to the digital to analog converter circuit and since the upsampling is done to a higher sampling rate, the analog filtering can be done at a higher filter frequency of half the sampling rate. This causes the artifacts to happen in a higher frequencies too, mostly outside the audio band. Digital audio works with square waves like signals that require steep voltage changes and thus instant current. This is where the switch mode power supply excels, but these use switching at very high frequencies and therefore generate a lot of noise on the power lines in the ground plane. They have the advantage of being very efficient. Very little energy gets converted to useless heat. Basic designs are also very cost effective. But if you need to have very low noise figures, as you would in a DAC, you need to filter the output of the power supply and do that without slowing it down, as simple filtering will do. So there are four main factors that influence the sound quality of a DAC. Jitter, linearity, reconstruction filter en power supply. It is safe to conclude that low jitter is the most important factor to the sound quality of a DAC. But a poorer power supply will cause poorer jitter behavior and an input signal with a lot of jitter might ruin this audio quality as well. In my set of one, I have used the same DAC for some years now, the MyTech Brooklyn. Initially the first generation and currently the Brooklyn bridge, that is almost identical, but has a network bridge integrated. The sound wise, there is a little to no difference between the DAC function of both. I use them with the SBooster BOTW PMP Eco MK2 12-13 volts so bypassing the internal switch mode power supply. That can easily be done since there is an external power connector on the rear. The initial source was an Apple Mac mini running run and connected over USB audio class 2 connection. That was followed up by the Sonora MicroRendu Network Bridge that gave a clear sound improvement. Resolution was better, there was less stress and the lows had more texture. When the MicroRendu had to be returned, it was replaced by the SOTM SMS200 Network Bridge that gave just a very small improvement over the MicroRendu. A real big step was taken when the SMS200 was replaced by the SMS200 Ultra. It was like having a new stereo altogether. Remember that we are talking digital signals only and I'm sure there are people that can't imagine the impact of this change. Then I heard of the Syntax power supply, a hardwired hand-built 6.2 amps linear power supply, specially developed for the MiTech Brooklyn. It appeared to be an 8 amps design fused at 6.2 amps en did wonders for the Brooklyn. The switch to the i-conversion again gave some improvement and at 1200 euros it should. The latest change was replacing the SMS200 Ultra Network Bridge by the Auralic Aries G2 digital transport, as Auralic calls its network player. I use it mainly as network bridge for Roon. Again the sound quality went up a notch or two, of four depending on the size of your notches. I know they are significant jumps monetary wise and of course being a company I usually pay a different price, no VAT, the European sales tax and the remaining amount is tax deductible. But the sound improvement between the SMS200 Ultra and the Aries G2 again is impressive. I can't judge your financial position and other personal factors that define how you value money and how you value sound quality. But I can judge the sound quality difference, at least in my perception. We have seen in the beginning of this video that in a DAC there are four factors important to the sound quality. Jitter, linearity, power supply and reconstruction filter. I have stated that linearity only will have minor effect on the sound quality, at least within the real world variations. The reconstruction filter of the MiTech leens on the MQA philosophy, also when non-MQA material is played. Other reconstruction filters can be chosen when MQA is switched off, but I like the MQA based filter. And that was a given throughout the upgrade process. The only two factors that did change and had a profound effect on the sound quality were the digital input signal and the power supply. The technical reasons behind this I will cover in a future video. I've been asked several times if it wasn't possible to build a DAC with the perfect power supply. And of course, that's possible, but it will have consequences on the price and the size of the housing. The same kind of question is why the internal streamer in the Brooklyn Bridge can't be made as good as the external network bridges I use. Again, the answer is yes and again it will have impact on the price and probably the cabinet size. I've not reviewed the MiTech Manhattan DAC too, that with the same features cost 2,5 times the price of the Brooklyn Bridge. I gues they made that it will sound clearly better with its over 300 watt linear power supply and the 995 euro costing network bridge card. And I'm sure the digital input circuits are better too. So yes, that can all be done but can or will you pay the higher price. If not, the upgrade path, like I described earlier, might be nice. In the end, you will have paid more, but you also enjoyed quality improvements earlier. I used the MiTech Brooklyn Series DACs as base for this video simply since that's my reference. The same will go for all kinds of other DACs, although not all have the provision for an external power supply. Using a network bridge is not the exclusive right of ruin. Both Sonori and SOtm offer working with DNA squeezebox emulation based on logical media server, music player daemon and airplay emulation. See the review of the Sonori and SOtm products. Using, for instance, Audivana 2 or Jbrif Media Center, you can send music to a network bridge dat support DNLA of you can send music from iTunes over airplay to a network bridge set to SharePoint. A quality streamer is, of course, also an option. If you don't already own a DAC, you could opt for a streamer with integrated DAC. And if you already have a quality DAC, go for a streamer or network bridge that only has digital outputs. In general, it's easier to get USB Audio Class 2 output better sounding than SPDIF or AES-EBU outputs. Although when these are very well designed on both sending and receiving side, there will be no sound quality difference. But these devices are few and far between. Oh yes, the Manhattan DAC 2 uses the ESS9038 DAC chip while the Brooklyn 2 and the bridge use the 9028. Something you might be able to measure but all other things being equal I would be surprised if there is an audible difference between those two DAC chips. And on that bombshell we are at the end of this show. I'd love to see you back next Friday at 5 p.m. Central European Time in a new show. If you don't want to miss that, subscribe to this channel or follow me on the social media so you will be informed on new videos around. If you like this video, give it a thumbs up. Many thanks to those viewers that support this channel financially. It keeps me independent en thus trustworthy. If you like to support my work too, the links are in the comments below this video on YouTube. I am Hans Beekhuyzen, thank you for watching and see you in the next show or on theHBproject.com. And whatever you do, enjoy the music.