Extreme_Boky Posted January 25, 2021 Share Posted January 25, 2021 Is the MAY DAC USB card / the USB interface powered up internally, or does it requires +5V supplied by the source (by the laptop)? Link to comment
Extreme_Boky Posted January 25, 2021 Share Posted January 25, 2021 That's what I thought. I hope the +5V coming from the source is used only for the hand-shake / initialisation. But, how would they separate the grounds (laptop ground - MAY DAC ground, using the isolator IC's, and still be able to power up the whole USB interface with the internal power supply. This would mix the grounds and make isolator chip redundant. It would be good to know exactly how it's done. Link to comment
Extreme_Boky Posted February 3, 2021 Share Posted February 3, 2021 I have been listening to DDDAC with WaveIO USB interface for 3-4 years. This was a DIY project that turned into a brilliant sounding, true NOS DAC. Extremely straight-forward with a lot of very low noise regulation (even the isolator chip on WaveIO board had its own, dedicated very low noise regulator). Many improvements over the original design had been made. The output from 33ohm I/V resistors was then taken straight to Aleph J clone (only 2 gains stages, last one working in a single-ended pure class-A config) - without a single coupling capacitor in the whole signal chain. Just wonderful.... with one minor annoyance -> DDDAC being a true NOS DAC (digital filters on DAC IC's disabled), suffered from the high frequencies roll-off + it had a fair bit of distortions (especially with higher sample rate material being fed to it). So, I was delighted to see a discrete, true ladder R-2R design that also measured exceptionally well. And I pulled the trigger and ordered May DAC. Well, what I've been looking for I managed to find in this DAC. It's an amazing blend of natural sound, plenty of details, and support of various file formats to allow people to obtain the sound that best suits their taste and the rest of their system. Outstanding! It is obvious that someone with great experience, true love and dedication for High-End HiFi, spent a lot of time and invested a great amount of knowledge to create May. I found the best results with true NOS, no overselling neither in hardware (May) NOR in JRiver that I use. Very close to analogue sound; very faithful to how the instruments should sound. Great dynamics (black background). Very quiet -> my Aleph J with 240Kohm input impedance picks up the tiniest amount of noise coming from the source - and this thing (May) is exceptionally quiet. And the total absence of distortions.... finally! What also helps is a minimal amount of noise coming from the PC - so, the CPU's that can be downclocked to 400MHz or 800MHz, low noise linear power supply, an OS that installs a bare minimum of applications.... all help. It is somewhat a different approach to oversampling to the max that May can support... but oversampling may work for others - that is completely fine and understandable. Link to comment
Extreme_Boky Posted February 8, 2021 Share Posted February 8, 2021 4 hours ago, John Hughes said: My source is a Stack Link II with LPS Ropiee XL endpoint (which is excellent) Hi John, What kind of power supply does Stack Link II use? Link to comment
Extreme_Boky Posted February 8, 2021 Share Posted February 8, 2021 Are they 19V DC? 2A? Link to comment
Extreme_Boky Posted February 8, 2021 Share Posted February 8, 2021 I am not sure what those trim-pots do.... but it seems the V out can be adjusted. If it's a true shunt regulator, then they may be providing for a current-out limit. Link to comment
Extreme_Boky Posted February 16, 2021 Share Posted February 16, 2021 That's what I expected, thanks for confirming. Once the handshake is done, the +5V is not required any more and it can be disconnected. Link to comment
Extreme_Boky Posted February 17, 2021 Share Posted February 17, 2021 2 hours ago, lpost said: Here's what Tim said in reply to my question about the 5V line. 'USB port needs 5V for handshake. So I just say these is zero advantage to make a cable without this 5V connection. Our usb module is isolated and does not use the 5V for anything other than the handshake. It’s self powered and ultra low noise voltage regulators. No worries. Hope you don’t bother with the usb non standard cable as it will only create issues with connections snd give no other advantages' Yes, I understand the above, thanks. The question is: do you believe that the 5V rail sitting in parallel with + and - USB data can influence USB data transfer in any way, or it can not... I like to disable the 5V DC coming out of the laptop, once the handshake is done.... even though the USB interface inside the May DAC has its own low voltage regulator(s). It's not what the laptop +5V DC does to the USB interface inside the May DAC; it's what it could potentially do to + and - USB data integrity (especially at those high transfer rates when oversampling; DSD256 for example)... along the full run of the USB cable. This is taking it to the Exterme... it doesn't have to be done, of course. Now, few of you may say: "+5V DC coming from the laptop can not do too much harm because there's no current running along that 5V DC wire, once the handshake is done!" ....but, without knowing the exact schematics and what type of IC's are involved during that hand-shake, I decide to turn OFF the 5V DC coming from the laptop once it's not needed any more. Link to comment
Extreme_Boky Posted February 18, 2021 Share Posted February 18, 2021 Those NS5 and NS9 noise shapers at 1.4112M sampling rate and 20 bit-depth look absolutely unbelievable. Thank you for posting the plots, you are a gentlemen 😇 Regards, Nick Link to comment
Extreme_Boky Posted March 11, 2021 Share Posted March 11, 2021 I ordered my May DAC L2 from Wildism Audio HK. Jo was exceptionally friendly and quick in his replies; he was replying to my emails pretty much straight away as I was clicking on "send" button. But the mazing thing happened when I ordered the DAC (from Hong Kong), and then received it in Sydney... after 4-5 working days. Stunning. Jo also found time to check the unit and confirm it was working correctly before he shipped it. Link to comment
Popular Post Extreme_Boky Posted March 11, 2021 Popular Post Share Posted March 11, 2021 The price of "tuned" versions seemed excessive to me. In addition, any tuning should be done once the player is inserted into the rest of the system, where it creates a musical presentation, a synergy that should blend with the room and suit individual need of the listener (owner). As such, applying the mods a priori will never yield the desired outcome. It's much better to do the final tuning with a blend of different interconnects, power cables and speaker cables, but only once the DAC becomes a part of the whole system. scintilla, Diavolo and kimgg 2 1 Link to comment
Popular Post Extreme_Boky Posted March 11, 2021 Popular Post Share Posted March 11, 2021 Nice! May sounds good straight out of the box. The funny thing is... I kept listening to it for a moth - moth and a half.... and thought to myself that the burn-in effect is not going to happen... buy it actually did. The sound suddenly became fuller, more relaxed, the bass gained extension, and the highs became even more crystal clear and natural. I do not know how and why exactly..., but be patient and it will happen for sure. It just proves what everybody keeps saying (Jo mentioned this as well few times in his email replies to me), that May needs 500 hours to start sounding at its best. Diavolo and kimgg 2 Link to comment
Extreme_Boky Posted March 23, 2021 Share Posted March 23, 2021 I have spent a lot of time experimenting as well. The most relaxed, detailed and natural sound I get is with LSN15 shaper, upsampled to 1.536Mhz, using poly-sync-lp filter and bit-depth of 20bits. It is an exceptionally enjoyable experience. Moving from 768KHz to 1.536MHz is like going from standard crystal oscillators to low phase noise ones (NDK SD to SDA). The bass frequencies are also fuller, better defined and fully integrated. Nothing sticks out; everything sounds just right. There's a caveat to the above.... I get much better sound (more natural and relaxed) with my laptop - battery powered, compared to NUC11 powered with a low noise linear power supply. The difference is striking. I noticed that many manufacturers are moving towards "zero noise" supper capacitors based power supplies, which they also use to do upsampling inside the DAC unit itself. I was just about to give up on digital and go back to analog (turntable and reel-to-reel)... and then along came the May DAC and the HQ Player. pavi 1 Link to comment
Extreme_Boky Posted March 24, 2021 Share Posted March 24, 2021 I can hear the difference with PLL ON, USB input. The sound is more spacious. Frequency extremes are more pronounced, they go higher and deeper. I like it better:) Link to comment
Extreme_Boky Posted March 24, 2021 Share Posted March 24, 2021 Asynchronous USB looks to be the perfect solution; you configure your PC for bit-perfect output and the DAC takes care of the timing totally independent of the timing of the PC. But there are posts on the Internet claiming that even in the case of an async USB DAC what is happening upstream is still affecting sound quality. Sending a signal to a DAC is done using a 100% analogue waveform/carier. The digital packets are superimposed on this, still analogue, waveform. But can software affect this wave? Is it done in bursts or is it throttled? The burst might induce periodic jitter, the throttle a constant jitter. Asynchronous USB is theoretically meant to make the USB receiving device immune to the PC, but..... it isn't immune. I can clearly hear the difference in sound when I use various laptops/desktops/NUC11. I found the lower the switching frequency of the CPU and the lower the switching voltage of the CPU (the switching voltages in general... on the motherboard) - the more pleasing and analogue sound I hear. Link to comment
Extreme_Boky Posted March 25, 2021 Share Posted March 25, 2021 4 hours ago, Miska said: Asynchronous USB Audio Class transfer sends data every 125 µs (8 kHz rate you can see sometimes leaking to DAC analog output). How much data is sent on this block is controlled by two things; 1) audio format (sample rate, number of bits and number of channels), 2) asynchronous feedback from the DAC. This data ends up in memory buffer at DAC which is then playing it out from there based on it's master clock. If the buffer level is dropping, it tells the computer "send me more", if the buffer level is increasing, it tells the computer "send me less". 44.1k base rates are not multiple of the USB clock, so the amount of data per transfer block varies all the time. While 48k base rates are multiple of USB clock and the amount of data per transfer block is more constant with less variation. But generally USB Audio Class is packet based transfer where the packet interval is constant but the amount of data per packet varies. Then there are some DACs that use something else than USB Audio Class and use so called bulk transfer, and they operate in totally different manner. But these also require custom drivers to operate. exaSound DACs are example of such. Thank you. Even though I was aware of the above, you worded it so nicely that it truly helps understand what an a-sync data transfer between PC and USB interface card means. Diavolo 1 Link to comment
Popular Post Extreme_Boky Posted March 25, 2021 Popular Post Share Posted March 25, 2021 On 2/18/2021 at 7:45 PM, Miska said: 20... You can actually see that from their linearity sweep measurement Fig 11, where the linearity begins to deviate at -120 dB which is equal to 20 bits: Setting DAC Bits to 20 won't affect noise floor when combined with LNS15, NS9 or NS5 noise shaper and high (>= 352.8k) sampling rates. This linearizes the D/A conversion removing distortion in low level signals while maintaining same noise floor. Note that Stereophile measurements are with flat TPDF dither, not with upsampling combined with noise shapers. You can even set DAC Bits to 16 when using the highest sampling rates and still the noise floor won't change as long as you use suitable noise shaper. In fact, setting DAC Bits to 20 and using for example LNS15 shaper at higher rates, digital noise floor at audio band is lower than it would be with DAC Bits set to 24 and TPDF dither, and without distortions. This is whole point of noise shapers; allows you to use linear region of the DAC while keeping or improving the dynamic range. But for the magic to happen you need higher sampling rates, noise shaper, and then the DAC's analog reconstruction filter does the rest. Here is example from Spring 2 (these were measured before LNS15 existed)... 1 kHz tone at -120 dBFS, with DAC Bits set to 24 (at 1.4112M sampling rate): Here with DAC Bits set to 20 and NS5 noise shaper at 1.4112M sampling rate: Here again the same, but DAC Bits set to 16, NS9 noise shaper, 1.4112M sampling rate, very little noise floor increase at 90 kHz: With NS5 shaper and DAC Bits set to 16, at 1.4112M sampling rate, you would begin to see noise floor increase above 60 kHz. So if you'd drop the sampling rate to 705.6k instead, the noise floor rise with 16 bits and this relaxed noise shaper, the noise floor rise would begin at 30 kHz instead - still above audio band. With DAC Bits set to 20 and NS9 shaper, at 705.6k sampling rate, you still have flat, unchanged noise floor. On 2/18/2021 at 7:55 PM, Extreme_Boky said: Those NS5 and NS9 noise shapers at 1.4112M sampling rate and 20 bit-depth look absolutely unbelievable. Thank you for posting the plots, you are a gentlemen 😇 Regards, Nick The benefit of LNS15 dither at 1.536MHz, using poly-sinc-lp filter and 20 bits of bit-depth are undeniable. This is my favourite combination. Nothing comes close to it... and I can no longer listen to anything else... It is like hearing all the details crystal clear, with great definition at all frequencies, firmly defined bass, shimmering highs, great width and height layered right in front of you. Truly enjoyable. But the best thing is in fact how the whole presentation blends together in the "right" way, as one would expect by drawing a comparison with the best analogue reproduction, with no hint of digital glare and associated tiredness. This is truly exceptional. lpost, w1000i and Diavolo 2 1 Link to comment
Popular Post Extreme_Boky Posted March 25, 2021 Popular Post Share Posted March 25, 2021 1 hour ago, lpost said: How many hours on your May? I’m right in the 200 hours mark and frankly some of it’s been exceptional and some of its been quite difficult. I just turn off the amps and do something else while it burns the hours. I did notice your previous post where you stated that the sound changed for worse.... This is what I experienced: Brand new May, right out of the box - very nice even with a “raw” (non-upsampled) 44.1KHz material. The whole spectrum was there (highs as well !!). Nice and spacious sound, very pleasant. There was no "dullness" that is sometimes associated with NOS DAC's. The rising edge attack was also there. I was impressed. It was also very natural; especially the string instruments. Piano sounded better in DSD…. the piano with PCM in NOS had that “clingy” harmonics that are sooo difficult to get right with a true NOS and non-upsampled material. This was the only negative that I remember. Around 200-300 hours’ mark: I noticed that the high frequencies have deteriorated somewhat...but only ever so slightly; the sound was shut-in, the high frequencies recessed. I am not sure why....I am also not 100% sure that this was indeed the case…I know, it’s funny but I do think that something was not right at around that 200-300 hours ‘mark. I just left May working with upsampled (1.536MHz) material, but I was also feeding it the DSD (256x) material... 50/50... 24/7 for around 4-5 days. Now I am at almost 3 –months‘ mark and May sounds lovely. I feed its balanced analogue-out straight to Aleph J with no capacitors in the whole signal path (apart from the speakers’ x-over). The interconnects and speaker cables are pure annealed silver ribbons and the silver alloy ribbons – respectively. I also use solid core power cables exclusively, a combination of pure copper, pure silver or a combination of copper – silver plated and then gold plated….This is my fine-tuning approach to achieve the most natural sound. The speakers are Dynaudio. The USB cable is Audioquest Coffee (I think it’s Coffee...). I have been building amplifiers and DAC’s, doing high-end modifications and playing with electronics all my life. My friends are musicians and my kids play musical instruments (acoustic guitar and violin). What they keep telling me is that everything sounds really lovely and natural, exactly how it is supposed to sound, with May, minimalist approach (I have only 2 gain stages in that Aleph J that I built, the second one working in pure class A, single-ended) and HQ Player with settings I posted above. I was just about to give up on digital sound reproduction, and then May and HQ Player came along (and the improvements in PC-to-USB DAC transmission – aka a-sync, for which we are eversograteful!). Also, people are finally realising that importance of a very low phase noise clocks/oscillators (NOT only low jitter per se)… heck, we are finally able to measure this phase noise at 0.1Hz and lower, properly, and at a reasonable cost. So, it took only 2-3 decades to get digital sound reproduction to sound decent. MichaelHiFi, fds and lpost 3 Link to comment
Popular Post Extreme_Boky Posted March 26, 2021 Popular Post Share Posted March 26, 2021 At those transmission frequencies, between the PC USB port and the DAC USB port, the amount of braid AND the way that braid is terminated to either (to both) USB shell metal cases, is of paramount importance. Next important thing is the impedance of the USB transmission line; not many manufacturers get it right - some (very boutique ones) do not get it at all - period. It should be 90 ohms. But, many expensive cables get this one completely wrong, and then we have reflections and dips that are clearly visible - reflections are particularly nasty. Then, there is a +5 V DC line there as well.... just to make things very difficult to get that USB data line impedance right.... So far, out of many that I checked, the one cable that got it right is Supra USB cable... Next, the USB line wire material makes difference as well. Many would say it's 0's and 1's and it is impossible that the DATA+ and DATA- cable material (metal) could ever make a difference, but it does; huge. John Hughes and 87mpi 1 1 Link to comment
Extreme_Boky Posted March 26, 2021 Share Posted March 26, 2021 6 hours ago, lpost said: Looks like I'll probably part with my AMD server with linear supplies since a bog standard Intel PC from 2017 equals or beats it in SQ and plays 1.5M/20bits without issue to the May. Saves power too! The USB input on the May is something special to not hear any difference between these two classes of computers/power supplies. ...just remembered that HQ Player caters for an on-the-fly phase inversion.... try that as well. Link to comment
Extreme_Boky Posted April 8, 2021 Share Posted April 8, 2021 Well, to start: - you would not have a detrimental effect of contact resistance X 2 (RCA's / XLR's) on sound quality - same applies to one interconnect cable (which you would not have to use).... each cable will have specific capacitance, inductance, resistance and the cable material (copper, silver) would also provide their own coloration - one less HiFi unit to pollute the power outlet Now, here comes the pre-amp in itself: - switches / potentiometers.... still only contacts / wipers / relays, all causing sound degradation - resistors, capacitors, PCB traces... same as above - internal hook-up wiring, PCB design => additional capacitance , inductance, resistance - active elements (transistors / valves); each gain stage will introduce a bandwidth limiting, phase shifts (that will not be the same for the full frequency spectrum, even audio spectrum)... Link to comment
Extreme_Boky Posted April 10, 2021 Share Posted April 10, 2021 Maybe the interconnects/RCA/XLR sockets & plugs and the inherent contact resistance introduced by all of them/those + the internal hook-up wiring to that volume pot and back from that volume pot... => has something to do with the overall impressions you experienced? Link to comment
Extreme_Boky Posted April 10, 2021 Share Posted April 10, 2021 Oooh, I forgot another important factor: the volume pot should be preceded by a gain (gain of 1) stage of some sort (valve/transistor) to ensure high input impedance for the source ....and.... be followed by a buffer stage (another gain stage), that will ensure a very low output impedance for the amp. Of course, the above is a good practice; however, it can be omitted... but then you'll have a varying output impedance, as seen by the amplifier (both, undesirable scenario and very high output impedance -> at most of the volume settings) ...and... a non-perfect input impedance, seen by the source. ... those gain stages, that should be used if the volume pot is to be implemented correctly, will require... a power supply, low noise of course,... Summary: measuring a volume pot in isolation does not mean anything.... we have to consider its performance within a contexts of actually controlling the volume in real life situation. And that real life situation includes all of the above elements that will provide sound coloration and will defenetly have a detrimental effect on overall sound reproduction. Link to comment
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