Popular Post OAudio Posted April 1, 2021 Popular Post Share Posted April 1, 2021 3 hours ago, hopkins said: The question remains of what is a "well engineered USB board" ? If it were so simple to answer you would not see Taiko investing so much in the development of their board, and keeping it "secret", and you would not have audiophiles tweaking endlessly their sources to prevent noise from polluting the DAC (since there is no perfect galvanic isolation on the DAC side for a USB input). The noise has multiple sources (not just the clock) and all components matter, including on these small boards. From experiance, in an engineered approach the main levers that need to be pulled on are: Timing (inc usb and upstream PCIe clock quaility), Signal integrity (inc usb transmission, detection cable effects and upstream PCIe comms), PSU quality and matching (inc differential noise between PSU systems in the USB card, PC and DAC) Managment of conducted noise, PC to DAC. Chipset selection Lesser items such as EMI and vibration also need to be covered off. I put the linked post up in a thead about USB not being bit perfect. It dosent frame all of the above problem space but there are a hand full of areas touched on in a little more detail that IMHO are some of the engineering challanges that need to be addressed. OAudio. Exocer, kyoya78 and One and a half 3 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
OAudio Posted April 1, 2021 Share Posted April 1, 2021 5 hours ago, matthias said: There was no disclosure by Emile, he said it is an "industrial" one. Matt Renasus UPD720202 from the package and circuit's pin out. The -711 variant is the -40 deg C temp range otherwise not sure what would attract the "industrial" commet if not this, there are only two variants. Elberoth 1 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
OAudio Posted April 1, 2021 Share Posted April 1, 2021 2 hours ago, wittao said: Yes, we are using the same. They are very nice looking boards in your pics. I had noticed the UPD's 😉 thanks for confirming. Looks like you are also using the 701s with ROM which is the way I went as well. I have some 711s I might have a look at them again. My understanding was that they are for embedded use where BIOS writes the firmware blocks to the chipset at boot time. That "industrial" comment has me wondering if I missed a way to use these ? OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
Popular Post OAudio Posted April 14, 2021 Popular Post Share Posted April 14, 2021 Hi, This is the OAudio RealStream USB card which I hope people will find interesting. It's designed and constructed without compromise for what I think might be the ultimate in USB sound reproduction. Sound quality is best simply described as "next level". A few details: Highly developed master USB RealStream clock subsystem incorporated onto the card. 12 LDOs for people that count, many more commonly found in applications like top end RF test equipment. Two user configurable USB ports Both ports No1 and No2 can have USB chipset firmware changes applied to modify the USB chipset's transmission characteristics. In addition Port 1 has a bespoke system controlled via setting controllers at the rear of the card to allow Port 1's USB transmission signal integrity parameters to be modified to suit down stream system and musical taste. Various Power options including PCIE sourced or dedicated 12 volt to rear of card. No plans currently to offer this commercially but without a doubt listening to it, I think it is a contender for the title of this thread Enjoy. OAudio Dev, 87mpi, Marcin_gps and 6 others 2 6 1 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
Popular Post OAudio Posted April 14, 2021 Popular Post Share Posted April 14, 2021 1 hour ago, Exocer said: Thanks for sharing @OAudio. So this card is voiced for a server you will be offering as well, correct? Exciting times. Cheers, -Rob Indeed exciting times, thanks Rob, Yes that's correct it is intended to be part of my music server and was developed primarily for use in single and dual core c621 systems. There were a number of iterations pro of concept and prototypes to confirm the way the card should be designed. Voicing will obviously be spot on with c621 systems but in other servers its been remarkably consistent as well. vhs, Exocer and 87mpi 1 2 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
Popular Post OAudio Posted April 14, 2021 Popular Post Share Posted April 14, 2021 29 minutes ago, Dev said: @OAudiothe card looks very similar to the Taiko :-) it looks like you guys sharing the same reference design. The user configurable USB ports are an interesting addition. Why not offer it commercially ? Hi Dev, Haha you have some thing there. The Taiko, Core Audio (very nice looking design) and my card have all settled on the same USB host controller chipset and the "house" colour scheme for high end USB cards of black and gold :-). The card pictured was built in January this year after 5 months of very intensive development work, but pulls heavily on earlier ideas I had and projects going back a number of years. There was a lot I wanted to packed into the card so its actually had to be larger than the other designs I think and uses a full size PCIE blade. It has been in a 2u case but it was defiantly a tight squeeze. My aim is that the components I am producing will by used in the in the server I am working on. I am targeting a very high level of sound quality performance so having the flexibility to change individual components where I need to specifically to suit this application is important rather than producing components for general use. Gavin1977 and wittao 2 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
Popular Post OAudio Posted April 14, 2021 Popular Post Share Posted April 14, 2021 No argument there Marcin and full credit. Like a good wine I think it has aged well and is still an excellent choice. I was very close to going with the ASM3142 which I think you also use I just checked your card also has the high end black and gold "house" scheme to that's a full house wittao and Marcin_gps 1 1 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
OAudio Posted February 3, 2023 Share Posted February 3, 2023 I am working on a new card at the moment (listening to it as I type) and plan to provide an update after posting here about my earlier USB RealStream card Its been something of a mission, like many of us, I have always found USB to be "broken" to a greater or lesser extent for high end audio. I first started using and working with USB in 2007 and have been gritting my teeth listening to its digital signature stamped on music since then . The technical challenge of streaming over USB in really high fidelity systems is without question a many headed beast. Just look at threads here on Audiophilestyle and the countless threads elsewhere discussing what might be happening to fragile music streams as they are piped from server/streamer to DAC over USB. Finally eighteen months ago for me it had to be either fix it or look to other standards for an interface. An objective since then has been to create a genuinely transparent USB interface regardless of the work required. And, I think its finally done . The card will be PCIe but unfortunately it has to function a part of a broader system with bespoke interfaces so it cannot be made generally available. Sorry. It will be a recognisable PCIE card though in a few months, so I will post some pictures here when its finished. I hope they will be of interest. marfanuk 1 OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
OAudio Posted February 18, 2023 Share Posted February 18, 2023 On 2/17/2023 at 12:20 PM, wittao said: In addition about Crystec's 957 series oscillators: the theoretical parameters are ok and gives to the engineers important informations. Earlier (5-6 years ago) we used that Crystec oscillators in our USB/SPDIF converters 24 - 24.576 - 22.5792 MHz freqs and works well but unfortunately in the PCB the oscillators working different then alone connected to the measurement equipment... -90dB@10Hz is a typical phase noise at that oscillators. We dropped them finally and started to develop our own oscillators. For an £10-20 part they offer amazing performance however all of the "Femto" clocks I have looked at are limited by their BOM costs and formfactor limitations. Once you load their outputs they are unpredictable for high level audio use. Drive even a 50 ohm PCB trace (in fairness they are not really spec'd to do this) let alone coax and be prepared to see audio performance pulled all over the dial. Of course you can use them to drive high impedance loads over very short trace lengths but even here the outputs can struggle. I have spent months and months understanding these problems and working out solutions. These devices fundamentally offer decent close in phase noise performance and excellent phase noise floor performance away from the carrier frequency. Here the above limitations are fixed but the solutions cost many 10s of times the cost of the "femto" clock itself. Well worth the effort though in terms of musical performance . OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
OAudio Posted February 18, 2023 Share Posted February 18, 2023 15 hours ago, Jarek_Jcat said: This discussion is heading in a bit wrong direction, as clock phase noise, important of course but not the only aspect of good sounding clock. Same as noise of power supplies. If we compare Jcat Initio3 and Optimo3Duo, even thou they share same circuit design, have more or less same PCB and noise wise measure exactly the same, they do sound different and Optimo3Duo is significant upgrade over Initio3. Same goes with clock. There are so many other aspects affecting it’s performance. From power supply and it’s distribution, buffering, signal distribution, output stage, PCB design and many more. Also removing oscillator from USB card and it’s power supply equation, affects SQ. All that matters and was addressed in Master OCXO module design, and is reason it looks quite complex. Master OCXO is step up in phase noise performance over oscillator used on Jcat USB card, but all in all from sound quality perspective it is much more complicated. kind regards Indeed, phase noise performance only counts when it is delivered directly onto the pin of the device you are driving. Not withstanding the oscillator's performance, implementation is everything. I'm not sure that I would say Master OCXO module design is quite complex though, here we are developing the firmware for the imbedded micros that control both the clock system's functions and the USB card . Still a good looking board and defiantly a good move to take the clock off the USB card IMHO. OAudio Ltd. OAudio Supreme - music server. OAudio RealStream - digital audio components. Link to comment
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