Jud Posted January 21, 2016 Share Posted January 21, 2016 Rob, have you had a chance to mention to your engineer friend the test I proposed to see if your Disruptor is operating as you have suggested it might? One never knows, do one? - Fats Waller The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature. Link to comment
robpriore Posted January 21, 2016 Share Posted January 21, 2016 Rob, have you had a chance to mention to your engineer friend the test I proposed to see if your Disruptor is operating as you have suggested it might? Hi Jud, thanks for asking. Here's what he said: Impulse test is theoretically useful measure for filters. It basically shows how the filter shapes and delays signals in the time domain. It might be possible to construct an impulse in MATLAB the same way that I made the sine waves and then send this through the DAC chain, but I don't know how well we could test this. I think the sine test is more representative as it gives more time to sample and FFT the signal. However, the impulse test would give the time domain response that everyone wants to see. Maybe a square wave test would show the same thing and be much easier to capture on a scope. Let me mull it over and see what I can come up with. As you can see there are challenges, perhaps he'll think of a way to do it. Link to comment
CR250 Posted January 22, 2016 Share Posted January 22, 2016 Hi Jud, thanks for asking. Here's what he said: Impulse test is theoretically useful measure for filters. It basically shows how the filter shapes and delays signals in the time domain. It might be possible to construct an impulse in MATLAB the same way that I made the sine waves and then send this through the DAC chain, but I don't know how well we could test this. I think the sine test is more representative as it gives more time to sample and FFT the signal. However, the impulse test would give the time domain response that everyone wants to see. Maybe a square wave test would show the same thing and be much easier to capture on a scope. Let me mull it over and see what I can come up with. As you can see there are challenges, perhaps he'll think of a way to do it. Rob, you have more excuses than a politician with bad poll numbers. Link to comment
jabbr Posted January 23, 2016 Share Posted January 23, 2016 I love your Buckaroo Banzai pic! I thought I recognized that. Big Boo TAY! Don't tug on that ... Have you considered that if you kill the power connection from the source, it means the power never leaves the chip itself, so maybe it can't leak into the data lines in the first place. Just wondering if you considered that possibility, because you say to everyone that "replacing the power supply provides limited benefit" but that is not the experience I have had personally, nor my many clients. John Swenson has written much about this topic, the way that suboptimal SI on data lines can transmit noise between systems. He does a great job of explaining some widely accepted principles of high speed digital design. One of the reasons that high quality power is important is that it affects the phase noise profile of the clock oscillator it is powering, but that is not the only thing that affects phase noise (for example). There are other types of noise to be considered as well. Another principal is that the circuit needs to do more work to recover the data when SI is suboptimal and this itself generates more noise. Yes power is important but not the only thing that is important. Think about it this way: a good USB DAC receiver doesn't use USB power at all, instead properly isolating the input USB signal from the output I2S signal which is itself repowered and reclocked. Custom room treatments for headphone users. Link to comment
robpriore Posted January 26, 2016 Share Posted January 26, 2016 Don't tug on that ... John Swenson has written much about this topic, the way that suboptimal SI on data lines can transmit noise between systems. He does a great job of explaining some widely accepted principles of high speed digital design. One of the reasons that high quality power is important is that it affects the phase noise profile of the clock oscillator it is powering, but that is not the only thing that affects phase noise (for example). There are other types of noise to be considered as well. Another principal is that the circuit needs to do more work to recover the data when SI is suboptimal and this itself generates more noise. Yes power is important but not the only thing that is important. Think about it this way: a good USB DAC receiver doesn't use USB power at all, instead properly isolating the input USB signal from the output I2S signal which is itself repowered and reclocked. I thought this was pretty interesting, his comments about ethernet too: [h=5]Hi Rob,[/h][h=5]First let me say that I’m the worst person at articulating what I hear so if I don’t make sense, it’s me not you. Second, I quiet like their.. umm.. format. A similar thing I had before was an iFi iPurifier which is a rigid piece and I always felt it must have loaded my usb port funny (as in supplying a moment/torque where there’s supposed to be very little) so your seem more suitable for sticking on the back of a DAC and forgetting about it.[/h][h=5]So what do I think of your disruptors sound-wise? I use them in 2 different setups. The first is my umm.. desktop setup using an Antipodes DX server into a Schiit Gungnir (old version, but USB gen 2) and then to a Cavalli Audio Liquid Gold headphone amp, ending up with a pair of LCD3’s or HD800. With this setup, (using LCD3’s) notes seem tighter. It’s only marginal, but there’s definitely more bite to guitars and drum beats. Definition seems better all-round which is nice. The changes are subtle, but then again, as far as USB sources go, I think my Antipodes DX is one of the better ones out there. (I’ve tried a few other USB tweaks and actually found no improvement at all, so well done!) Definitely “tighter”. Like everything went more “Dire Straits”, if you see what I mean.[/h][h=5]The second set up is mac mini->PS Audio Direct Stream. This is a speaker setup but at the moment I’m using a really crap amp driving budget speakers so hardly fair. A $6k DAC into a $199 amp and to $299 speakers! On this there’s certainly an improvement again in simply the… “clarity” of the sound. I can’t really point out where it is in the frequency spectrum, but it really did make the speakers sound a touch less confused like they normally do. What I really noticed with this is a little long so bear with me. My PS Audio DAC actually has an ethernet input – this takes files from a DLNA server into the DAC’s i2s input and from a budget SYNOLOGY NAS, this is the best input for this DAC, imo. While USB for this DAC is pretty amazing, ethernet beats it quite clearly. What’s nice about your disruptor is that it seems to take USB quite a bit closer to the LAN route. It doesn’t quite beat it, but I am now happy to compromise and go with USB’s combination of sq and convenience.[/h][h=5]So, sadly I can’t give you any jumping up and down with excitement type comments but I think for the price, these things are hard to beat. A complete no-brainer for anyone with a USB DAC and honestly, I think they will show themselves more clearly in lesser systems for sure. If I have the opportunity, I will try it on my lesser systems and see what they do.[/h][h=5]Congratulations on making something really great value in hifi. Such things are rare indeed. Best of luck![/h] Link to comment
Andyman Posted January 26, 2016 Share Posted January 26, 2016 Are you sort of implying / pretending that John Swenson wrote that to you? Link to comment
sandyk Posted January 26, 2016 Share Posted January 26, 2016 Are you sort of implying / pretending that John Swenson wrote that to you? He is implying/pretending that he came up with something new that is worthy of a patent ! Absolute rubbish. There is NOTHING new about what he has done !!! How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
devs Posted January 26, 2016 Share Posted January 26, 2016 Everybody's making fun of the poor man. USB Decrapifier Thread Bugs,Regens,Wyrds all that shizzle | Page 9 | Super Best Audio Friends Link to comment
robpriore Posted January 26, 2016 Share Posted January 26, 2016 He is implying/pretending that he came up with something new that is worthy of a patent !Absolute rubbish. There is NOTHING new about what he has done !!
Recommended Posts