Audio grade USB cables
My engineering advisor says "The whole point of differential communications schemes is immunity to common-mode noise." He also says you're right about ground loops, but that is "one of the most tangled webs you can weave in electrical engineering." It's ironic because all of this back and forth is well and good but it's only half the story. If you don't listen then you can't really understand what it's doing. In this case, the observations back the theory that unwanted noise from USB vBus affects the time domain. That in turn flattens the sound stage - makes sense that it would - and throws off spatial directions just enough to cause voices to bleed and shrill and harsh tones at times. |
Shielding will not reduce CM noise.. USB is differential, so the ground wire is not involved in the data transmission, however it does set the reference for the source qnd receiver.. If there are any ground loops in the system, CM noise will be present.. This can be measured with a scope, but the measurement needs to be differential, using differential probe with no earth ground affecting the measurement. |
Hi, would common mode (CM) noise show up on a scope? We did readings between using a certified USB 2.0 cable and the same cable with the USB Disruptor connected. The readings displayed the 5khz tones and we didn't see anything problematic. We may already be filtering it out, our solution is shielded. |
There is more to this issue than claimed here. It is certainly good to provide ahigher quality USB power source than that provided by the cable/computer, particularly for those USB interfaces that utilize the 5V in the cable.. The the other issue that is a primary cause of jitter is the common-mode noise in the USB connection.. Replacing the power supply will not fix this.. CM noise requires filtering in the cable. There are several companies that sell USB power supplies and there are several that sell filters.. None of these combine a really low-noise, fast-reacting supply withan effective CM filter, except Empirical Audio.. Our Power Block contains effective filtering with a custom Hynes-regulated USB supply. The filter will not adversely affect SQ.. In fact it will improve it. As for these things affecting the data, I have tested this and they dont.. My DAC does not have resampling in it and any data errors are immediately rejected by muting the DAC, or causing clicks. |
Thanks Williewonka. If it sounded better without the extra cable, no matter what type of cable, then it could be a shielding problem. The connector would have to maintain the shielding and maybe it's not as good at doing that as a properly constructed USB cable. That may account for the sonic differences you heard, especially if it was better without the extra cables. |
Rob.... Williewonka, the operating principles of USB Disruptor would suggest that the type of USB cable from the computer into the Disruptor would not matter, so long as it's a certified USB 2.0 cable. In my case, I tried several cables attached to the signal cable of the Doukmall cable and although the differences were small I could discern improvements between several cables - especially when using a higher quality DH Labs Cable. But even the DH Labs cable did not perform as well as simply connecting the Doukmall Cable directly to the computer. Perhaps the USB connector could have introduced problems? - I don't know, but it was very simple and a very short female/female adapter like this one http://www.amazon.ca/niceEshop-Female-Adapter-Adaptor-Coupler/dp/B00A4RI326/ref=sr_1_1?ie=UTF8&q... Without actually trying the Disruptor I am unable confirm your observations. But I do believe the Disruptor achieves the improvements you cite and provides a very affordable solution alternative to overcoming the inadequacies of computer USB power. Regards... |
Jaybe, check out this part of my site for some answers to your questions: http://usbdisruptor.com/how-usb-disruptor-works/ The Jitterbug may be filtering something out because I heard it on a very resolving system with USB Disruptor and it caused an unwanted ringing around one of the voices in Guinnevere by CSN. It was repeatable and was the Jitterbug. Maybe it doesn't play well with USB Disruptor, not sure, it really shouldn't matter though because USB Disruptor is really very, very, simple in terms of what it does, which is to disrupt the influence of the 5 volt power coming from the computer. We don't force the signal through any circuits, it's a very hands off approach in terms of the signal. That's why I said I don't like to knowingly filter anything when it comes to audio. |
Williewonka, the operating principles of USB Disruptor would suggest that the type of USB cable from the computer into the Disruptor would not matter, so long as it's a certified USB 2.0 cable. I tried testing it with a range of USB cables and I could not hear a difference. I have some empirical data that may help explain why it works. I've added that to my website: http://usbdisruptor.com/how-usb-disruptor-works/ I |
Jaybe - not a problem - I had to search all over when I started looking at why different USB cables perform differently. I originally "assumed" USB transfers would error check and resend - just as a computer communicating to a USB drive would - but that was not the case for streamed content. Regards.... |
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Jaybe - the phrase you quoted RE: "But one thing for certain..." is from one of my posts - so in response... I read it here... http://www.thewelltemperedcomputer.com/HW/USB_Trouble.htm
And here... http://www.beyondlogic.org/usbnutshell/usb4.shtml#Isochronous Isochronous transfers occur continuously and periodically. They typically contain time sensitive information, such as an audio or video stream. If there were a delay or retry of data in an audio stream, then you would expect some erratic audio containing glitches. The beat may no longer be in sync. However if a packet or frame was dropped every now and again, it is less likely to be noticed by the listener. And several other places on the web If that has since changed - I stand corrected. Regards... |
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I can tell you from many years as a Audiophile and experimentation and working in pro audio the noise on the 5 v digital line can be very dirty . i bought first a Jitterbug which does filter the incoming digital signal . Two can can strip out some of the fidelity of the music. the USB Disruptor has been by far the most out effective product used anywhere in my system and I have tried a lot of tweaks. and it was do simple to implement just plug it in to a outlet connect to your dac then plug your digital cable into that. The sonic benefits were like lifting a sheen or fog ,separation of instruments was clearly better ,yes even more so then the jitterbug with more Bass impact and depth of soundstage.even at 2 x the price a steal in my opinion,With a money back guarantee you have nothing to use . |
Or just add an UptoneAudio Regen and benefit from both the +5V separation and regeneration of data for a bit more money than the Disruptor but definitely worth the little extra. Add an affordable hand made Supra USB cable and you're good to go for a solid upgrade. If you like (even) more sonic improvement, the Curious Cable from down under is worth looking into. |
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Rob - I've just looked at your web site and at the pictures of the Disruptor and "in principle" it is very similar to the Doukmall cable...
Basically - As I see it, the differences between the two products are... The Doukmall product...
The Disruptor product...
The debate about the use of Computer Grade vs Audio Grade USB cables for audio data transfers will be ongoing and the outcome is always based on the "opinion" of a specific consumer. But one thing that is certain - asynchronous USB data transfers, as used in streaming to DACs, ARE NOT vetted for completeness by the DAC, i.e. it is not known whether the data sent by the computer actually arrived at the DAC intact - and as a result SQ can be affected. With all that said, I do believe the Disruptor offers an alternate approach to providing "clean power" to the DAC, which will improve the performance of any DAC/SPDIF Converter that utilizes power normally made available via the computers USB cable! It is unfortunate that I had not seen your product earlier, otherwise I would have purchased it - it just did not show up on my Google search at the time. :-( Regards... |
Mesch -here’s the cable... One side goes to the computer and the other to the power supply... Enercell 5V/1A AC-to-USB Power Adapter Charger or http://805onlinedeals.myshopify.com/products/new-enercell-5v1a-ac-usb-charger-purple-2730703-2-pack Please post your findings here - I would be interested to know how it compares - thanks Enjoy :-) |
I have the Audiophilleo with PurePower and run the USB Disruptor there too. The difference is the same, dirty USB power infects that product too. I think the dirty power is composed of super high frequency noise that is able to travel on the surface of components. It's hard to clean up, so it's best just to disrupt it for good. |
Sorry Willie, I live in southern Illinois. It seems that the Doukmall cable is a good inexpensive way to separate power from signal and probably would provide much of the sonic gain provided by the PurePower to the Audiophilleo. I would like to try the Doukmall in my 2nd system. It seems Doukmll makes several cables. Is there a particular make? |
Mesch - I’ve just been reading about the Audiophilleo product range and it looks very interesting. I would agree with your assessment, but only if the Pure Power option is used. The Doukmall cable addresses one basic issue...
The Audiophillio Products with the Pure Power option will also alleviate this issue - i.e. by NOT using the power provided via the USB port. THEN - they go to some extraordinary lengths to ensure extremely clean power is supplied to the digital circuitry. However, if the Pure Power option is not used, the Audiophillio USB-SPDIF Converter uses USB power. In which case, it too is subject to the same issues any other USB powered device is subject to.
Personally, I have tried many "experiments" with providing "clean" power - especially to digital circuitry and found it paid big dividends in SQ every time and the Audiophillio products seem to be addressing this to the highest order. It would be very interesting to hear Audiophillio + Pure Power compared to my Doukmall setup - I would imagine the sound is very nice indeed - alas, the price is the only thing stopping me. You wouldn’t happen to reside in the Toronto area would you? :-) Regards... |
Robpriore, Thank you for your post and answer. We think alike, in terms of minimalism. I also don't use a preamp, I have volume control inside of my DAC. I've also used stepped attenuator before, now it's digital volume control in my DAC. And I haven't noticed any loss of resolution, unless i go under 50% setting. this is my favorite volume control this far, and I own 4 diferent types of volume control. Personally, i would go diferent path - low power SET amp0, high-sensitive and ohm-stable speakers, and separate amps for bass drivers. That's how i do it, and it is the best sound i've heard. Pretty soon, I will modify DAC to power USB input (amanero), from DAC, not USB cable. I will report with the changes in sound. """""This becomes maddeningly apparent after using USB Disruptor, and I can't think of a single audiophile upgrade that accomplishes so much for so little cash." That's because you make them. """"" Maybe. But maybe it is also because there is a logical science behind this product, and it actually works. I think it should. I would order it and try it, if I couldn't modify my DAC. |
Audiobb, I think in that scenario USB Disruptor would not be needed at all. The power would come from the DAC itself, just a 5 volt lead. And The DAC maker could leave the 5 volt pin off the USB connector on the DAC to guarantee dirty USB power can't leak into the DAC from the computer. I would bet that some DAC makers have figured out the problem and basically install a USB Disruptor type solution inside the DAC, which would be a great way to make a great sounding DAC, and then charge a big dollar amount because the sound is very different, and it's obvious to everyone that it simply sounds different. I'm serious, the sound with USB Disruptor is different. In my opinion, and to my ears, the sound with USB Disruptor through my reference setup is the best sound I've produced in 25 years, and I think it's the best sound I've ever heard, on any system. It's not loud, I mean I could spend more to add 8 additional speaker drivers and more amps but that would only make it louder - it would provide no more clarity or detail. I'm a total minimalist with the analog section of my system, having abandoned chunky preamps in favor of a single input passive preamp. The passive pre utilizes a state-of-the-art stepped attenuator, which is a volume control, but the signal passes through a single resistor only, and the volume control has 27 positions each with a single resistor for each level, so the total is 27 resistors. Bottom line on this, the signal is passing through what may be an absolute minimum in terms of volume, and for sure in terms of the preamp since there are no preamp circuits. It's hard to imagine a more pure circuit. After the pre it goes to my custom Odyssey amp, then to my Von Schweikerts. Again, it's hard for me to imagine a better sound - the Scanspeak drivers in the Von Schweikerts and the Sanken transistors in the Odyssey are found in some of the most expensive and best sounding audiophile gear- at any price. Buying another amp of similar quality, just more powerful, wouldn't help me do anything but go louder. The point of this is that I didn't use USB Disruptor in this system until recently. And because of the difference I now know the cause of my digital woes to be dirty USB power. Had USB Disruptor been invented years ago I may not have upgraded my Adcom amps or Mirage speakers, because the problem I was trying to solve, unbeknownst to me at the time, is caused by dirty USB power. The symptoms include shrill or sharp tones, a kind of graininess to the sound at times, and the silent spaces between notes are often lost. This becomes maddeningly apparent after using USB Disruptor, and I can't think of a single audiophile upgrade that accomplishes so much for so little cash. |
Mesch - On the Doukmall cable there are 2 legs and a total of three USB terminals. The signal and power legs are joined at a shared B terminal that is yellow. The A terminal of the signal leg is also yellow. The A terminal of the power leg is black. I can't say whether the signal leg lacks power leads or if those leads are present and simply not connected. I did not think to try and connect only the signal leg of this split cable to confirm voltage is carried solely by the power leg, though that is my assumption; an easy thing to check, however. Hope this answer helps you. |
Hi Robpriore, I really appreciate audiophiles who contribute to tze hobby. Your USB disruptor certainly seems like a step in that direction. I agree with you - 5V in USB cable is a problem. Definitely. If one is able to completely cut it off (let's say, makes a DAC with USB input powered from the DAC itself) - and then makes a USB cable without +5V leg - would you USB disruptor make a difference in such case? USB cable then would have + DATA, - DATA, and -5V (ground) legs - and that's it. Would your product make any difference in such case? |
Mapman, I tried a lot of USB cables while testing and they all sound equally bad running direct from the usb output port. When you disrupt the computer's 5 volt USB power line in many cases you get a really big improvement. And this improvement was not due to USB cables of one flavor or another, because when AB testing those units running the disruptor I couldn't tell one from another. This finding is consistent with the logic of digital signal processing. There should not be a difference, not according to what we know, real and theoretical. However, it is likely that some USB cable designs do in fact reject some of the USB power noise. But they can't get rid of it completely. And in that case one USB cable would in fact sound better than another, having removed some of the noise would improve the entire signal chain. But it's still incomplete, and most people have not spent $1000+ on their USB cable to get that benefit, so in most cases it's very incomplete. And that means dirty power is leaking into the entire signal chain and polluting everything all the way to the speakers. In that case it gets to be a very frustrating process of elimination to find the cause of the problem. In my case it took six years of experimentation to get to the truth. |
I am a software/systems engineer, but I use very basic USB cables mostly AmazonBasics which are not expensive and seemingly well made. I have trouble getting my arms around what makes any digital cable worth a lot of money. Most any I try sound pretty good and leaving me uninspired to try anything different. I have no such problem with analog ICs and power cords. I have heard clear differences in sound quality with these. I think I can with speaker cables as well though I have not tried very many different ones over the years. |
Czarivey, do you connect your computer to your DAC with one of those Walmart USB cables? Because if you do, then you're being robbed of dynamics, atmosphere, tones that soothe, and silence between notes. It's not the USB cable, it's the computer. And you can't fix it unless you disrupt the dirty 5 volt power that the computer generates. It's common sense this power is dirty - think of the millions of circuits those electrons must flow through, think of hard drive noises, and all the operations being conducted in the background. That causes noise. And that noise goes into your stereo if it is physically connected to your computer by means of a USB cable. Even if you have a device, it doesn't matter what it does, it's still connected to the computer, and that is the problem. So to make your USB DAC sound how it's supposed to sound, you need to supply a clean power connection to the USB cable, separate from the computer. There are few products that do this. Some of them have been mentioned above. With one of these products your Walmart cables will sound at least as good as the expensive audio grade USB cable I used to test USB Disruptor. Good luck. |
Yup...the signal leg of the Doukmall USB cable plugs into a USB port on your computer. The power leg gets plugged into a 5V AC to USB power adapter as used for charging cell phones, etc.. This must be purchased separately but they're pretty ubiquitous and cheap (under $15). The "joined" end gets plugged into your DAC. Less than $75 for the whole shebang. |
Robp - You are correct - you do need a USB power supply adapter Plugging both ends into a computer is not advised - I did try it and although it was still better than my DH Labs USB cable, it did sound much better when plugged into the USB adapter I use an adapter like this for $5.99 Enercell 5V/1A AC-to-USB Power Adapter Charger I tried several adapters, ranging in price from $5.99 to $25 and ranging from 0.5 amps to 2amps and the one above performed the best. I've since tried it with my new Samsung Tablet adapter and it did not sound too good with that either - so the power supply is critical. Regards... |
And one more thing about the DoukMall product: if you plug it into a separate USB port on your computer to act as the power then you're not disrupting the computer noise at all. For that product to work like USB Disruptor you have to plug it into a completely separate wall outlet. Doesn't look like it comes with that piece. So it's incomplete! |
For those of you who want to buy a Chinese made cable, be my guest. The fact is that this technology really works and few tools address the problem. The DoukMall product doesn't actually come with a power supply. USB Disruptor is hand made in the USA, tested by me personally, and includes an outstanding power supply for nearly the same cost as a Chinese made import. This is not a blatant advertisement either, it's sharing information with my audiophile brothers. We're mostly men, we spend a lot, and we demand a lot. I'm giving back to you guys by sharing my learnings, and if I can help you reach sonic bliss, then great. If you want to buy my product, good, if not, that's okay too. |
I followed Willie's advice (he's posted about this elsewhere) and bought from Doukmall on ebay (Chinese). The first cable they sent was dead but they replaced it even before they received the cable I was returning. It works fine and was quite a bit cheaper than some of the $200+ versions I've seen from "main-line" audio equipment companies. No affiliation with Doukmall. DoukMall ebay - USB w/separate signal & power |
