Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
I connect my Touch to the M-Dac via coax(by MIT). The plugin works fine with 24 / 192k FLAC's. It shows 24/191.999k though. I tried the USB connection too (Audioquest Cinnamon). I got it work and it showed 24/91.999k. However, there were clicking noises. I have not tried using it with a high-speed hubs yet. singasong's Profile: http://forums.slimdevices.com/member.php?userid=56581 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
JJZolx wrote: How does jitter get through an asynchronous interface? Isn't that a bit like talking about jitter on an Ethernet connection? John is probably talking about non async usb dacs (of which there are still many) - adding an issolator to these could easliy make it worse. In the cause of the M-DAC as the designer (John Westlake) recommends trying an issolator, I think you are safe assuming the clock is reasonably well issolated from usb jitter. Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
JJZolx wrote: How does jitter get through an asynchronous interface? Isn't that a bit like talking about jitter on an Ethernet connection? Good question, unfortunately things are not as simple as it seems on the surface. The supposition goes that as long as you have a local clock, the only jitter you can have is what is inherant to the clock itself, but there is more to it. It's primarily noise on the groundplane. Let's first look at how digital logic works. You have transistor circuits running in a high gain mode with a threshold which is some ratio between the VDD and VSS power nets (power and ground). The signals going between chips are not perfect, they take a finite amount of time to transition between a high and low (and low to high) state, the voltage ramps between the states. Exactly when those transistors switch is dependant on when that ramp reaches the threshold of the receiver, and that threshold is dependant on the instantaneous voltages on VDD and VSS. Thus any noise on either power or ground will cause the time at which the threshold is reached to vary, otherwise known as jitter. This noise on the supply nets comes from current flowing through the wires in three places, the chip itself, the package the chip is in, and the board the chip is soldered to. The first two are just influenced by what is happening in the receiving chip itself. Note that this includes all the input signals. Every time an input changes state current flows through circuitry in the chip causing noise which will add to jitter of other input signals and outputs. How much noise happens internally is extremely chip dependant. A very robust power network in the chip will generate very little noise, but a very robust power network increases chip size and cost, there is always a tradeoff here by the chip makers. Certain chip functions (such as recloking flops) can actually change the sound depending on which manufacturer and logic family is used, simply because of variations in internal power networks. Noise developed across package wires is similar to chip noise, though much simpler since it is JUST dealing with the I/O signals. Here smaller packages are usually better. The groundplane is where all the fun comes in, because here we can have chips whose signals are not connected affecting another chip, and processing going on in a chip affecting another chip. Groundplanes are NOT equipotential everywhere, currents flowing through the plane DO generate voltages across the plane. They are not huge, but they ARE there. Unless you are very careful about parts placement and groundplane design it's very easy to have circuitry on the board causing noise which can significantly increase the jitter of that ultra low jitter clock you are relying on to provide a very low jitter clock to your DAC chip. I hope it's obvious by now that this groundplane noise is not static, it ebbs and flows with the switching going on in the chips, which can change due to jitter on the inputs of THOSE chips. Not just jitter but things like packet timing (both USB AND ethernet) can have a big impact on the dynamic nature of this groundplane noise. This is why my prefered method is to have the USB receiver chip powered by VBUS with an isolator on the OUTPUT signals going to the DAC chips. This way the ground planes are completely separate and the noise caused by all the processing going on in the USB receiver chip cannot get get into the sensitive DAC groundplane. Jitter on the signals can still cause groundplane noise, but that is much less than the noise from the processing in the receiver chip. Ethernet has exactly the same issue (if not worse), ideally you would have a separate ethernet processor with an isolated groundplane so all the stuff going on in there is not producing noise getting coupled into the groundplane around the clock and DAC chips. For something like the Touch with an integrated processor there should be separate groundplane for all the digital stuff and the audio stuff (clocks, reclocking flops, clock muxes, DAC chip, S/PDIF output). So yes even an asynchronous interface with a local clock can be affected by jitter and other timing issues on the input interface. The causes and fixes are much more subtle and difficult to analyze than the first order effects such as PLL jitter. Getting rid of them in a design are much more implementation detgails such as exactly how the groundplanes are implemented and exactly where the chip are places and signals routed rather tghan broad catagories such asynchronous or PLL or ASRC. These are real and do affect sound but it's really hard to talk about in marketing literature! John S. JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
I found optical to a DAC (Cambridge Audio DACMagic) from my Touch (and then into an Arcam A85/Dynaudio Excite X12) to be better than coax. For a £4 spend it was well worth the experiment! gw43's Profile: http://forums.slimdevices.com/member.php?userid=11327 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
The USB isolators block a potential path for a ground loop through the ground of the USB connector of the computer (Touch in this case). Whether this is necessary will of course depend on the computer and DAC and how the power supplies are hooked up. There has been so little use of USB DACs with the Touch that all the reports I know of are using the isolators with regular computers, so may or may not have relevance for the Touch. The isolators themselves that I am aware of put the isolator in front of the USB receiver in the DAC, they all use the same chip. These chips DO add a significant amount of jitter to the USB signals themselves, whether this jitter winds up as jitter on the clock feeding the DAC chips (the only place where jitter really matters) is going to be VERY implementation dependant. In some DACs it won't get through to the clock, in others it will. So in some situations it comes down to a tradeoff between higher jitter and lower ground loop noise, or it may not do anything at all. Or it may make things worse! My personal favorite approach is to have a USB reciver running off the VBUS with the logic level outputs going through isolators (I prefer GMRs) to the rest of the DAC. This way everything having to do with the USB stays on the computer domain. John S. JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
JohnSwenson wrote: These chips DO add a significant amount of jitter to the USB signals themselves, whether this jitter winds up as jitter on the clock feeding the DAC chips (the only place where jitter really matters) is going to be VERY implementation dependant. In some DACs it won't get through to the clock, in others it will. How does jitter get through an asynchronous interface? Isn't that a bit like talking about jitter on an Ethernet connection? JJZolx's Profile: http://forums.slimdevices.com/member.php?userid=10 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
Does the USB isolator though just perform a familiar job to a mains filter? If you've got clean mains you don't really need one? I'm still to do extensive listening via USB compared to coaxial? Anyone else got the same setup? tank121's Profile: http://forums.slimdevices.com/member.php?userid=17169 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
main filter does not isolate the interface Touch to DAC not the same thing, nb I have no idea if USB needs isolation or not , if these products are used for non audio application to then they might have a real purpose (not just fleecing audiophiles ). Mnyb's Profile: http://forums.slimdevices.com/member.php?userid=4143 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
USB isolators are not the same as mains filters. As far as I understand it, isolators remove the electrical connection (grounds) which exists otherwise, and prevent the introduction of noise into the DAC and its digital and analog circuitry (some of which can be quite sensitive to such pollution). I think that PSU noise is more a factor here than Mains noise. One could achieve the same results with a USB-optical-USB connection, but this costs more than the £20-30 of an isolator. Isolators should not alter the signal and don't have any negative effect (besides cost and throughput limits which are above what is needed for USB 1.0 Audio)... as can easly be demonstrated with the MDAC and its bit perfect test. They do provide some added protection to the DAC (and are commonly used with USB experimentation boards and other testing equipment, for this reason). eiffel's Profile: http://forums.slimdevices.com/member.php?userid=46208 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
I must add that using the Mdac via usb is sounding sweet.Can I be bothered switching back to coaxial? I've never purchased a 192k track. tank121's Profile: http://forums.slimdevices.com/member.php?userid=17169 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
[SlimDevices: Audiophiles] Triode plugin with M-DAC
Just wanted to gauge from my fellow Touch and M-dac users the best combination. 1. With plugin and using usb cable 2. With plugin (set to digital out) and coaxial cable 3. No plugin and coaxial cable Please share your findings PS I'm using Belden based Coaxial and cheap usb cable. tank121's Profile: http://forums.slimdevices.com/member.php?userid=17169 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
I have my Touch connected to the M-Dac via coax and can confirm this works fine with 24 / 192k FLAC's. The M-DAC is limited to 96k on the USB input - so personally can't see any advantage in trying the USB connection as access to my (very few at the moment (1 album)) 192K recordings is what I was after. steve-g's Profile: http://forums.slimdevices.com/member.php?userid=52057 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
Re: [SlimDevices: Audiophiles] Triode plugin with M-DAC
I'm still waiting for my replacement M-DAC (Original unit had a defective relay and was returned in December!), so can't really write from experience. The USB connection offers one key advantage thanks to the asynchronous communications it enables (this should greately reduce jitter). It is limited to 96 kHz but should definitely be worth investigating. One other consideration is electrical isolation (mainly form power supplies pollution). You may want to try using a USB isolator (£20-30 from Olimex or Danish online shop) -Cable quality should not matter, provided the cable is good enough for bog standard USB applications-, or a Toslink/Optical connection with SPDIF (up to 192 kHz sampling rate if so inclined). From what I gather from communications with John Westlake, the MDAC designer, its likely that the best results will be achieved via the USB interface and an isolator. PS: John plans on designing a 192kHz USB interface for the MDAC, which may be even better, but that's still just a concept. eiffel's Profile: http://forums.slimdevices.com/member.php?userid=46208 View this thread: http://forums.slimdevices.com/showthread.php?t=94822 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
