Theoretical arguments are not in themselves convincing. Audio forums are replete them.
You really haven’t answered the query I posed: If as you pose there is substantial sound degradation with unfiltered USB, short of corrective measures, such as the FMJ, why aren’t and haven’t audiophile level cable, streamer and dac developers been talking about dealing with it as absolutely necessary and providing solutions? Has there been a conspiracy of silence, incompetence, or what all this time? Even AQ, centrally a cable company, took years to come out with the FMJ. Yet, it’s posted as an accessory, not a necessary element of using their USB cables.
Whatever the value of filtering – I don’t have an opinion – something doesn’t add up in the insistence of your claim (and the examples provided in the articles you linked).
The problem is directly proportional to the DCR RF ground differential, that’s why it was stated as such. You seem to want to adopt the hersey and not the proven facts, or even read the papers that educate you on the problems. Your choice, I’ve gone out of my way to help you with the physics that is reproducable and factually correct, ALWAYS and ALL the TIME. DCR between grounds is a fact of electronic life.
YOUR system ground network is at fault for external ground differential, not the devices that are designed to an ohmic tolerance on most grounds. There is no conspiracy. You have adequate ground or you don’t. RF, not being audible, can be tricky to pinpoint in BER excursions. A simple isolation device for mere pennies on a audiophile’s budget can put that to rest.
You don’t want an answer. There is nothing that doesn’t add up in the insistence of my “claims” because they are not a claim, they are the facts. But you’ll side with heresay? Again, the magnitude of the ground ground differential define when we hear it and call it a ground loop. The two articles that I can easily deduce you didn’t read show the problem in tests very plainly. This is not a liberal argument. Science just isn’t. It can be currently unquantified at times, but until the physics is valued in measurement, it is there to be found and never changes it’s spots just because we haven’t defined a test yet. In this case, we certainly have.
The problem is as easy as the factual DCR of a wire. Got any with no resistance? Most ground loops are below audability in a proper ground system.
This isn’t theoretical, it has been PROVEN and CONSISTENT. Grounds are not all at the same potential to a reference, it is impossible.
Wrong. They say that IMPROVEMENTS that are well defined and repeatable are just too good to be heard. Not the same thing at all. “We” say that done well and thorough enough in a resolving system they do improve things. The science of cables done right are measurable. We need to move on from ignoring that.
If you’ve decided that Fred and Rob at Lampizator NA are who you choose to believe then just buy a streamer with a USB output that fits your needs and an appropriate USB cable and be done. A safe starting point would be the same coax cable you like in USB. I’m partial to the Inakustik Reference or the Tubulus Concentus. Continuing down the current discussion path is pointless.
If you read my post, the challenge is general, not just Lampi, although Lampi would have all the interest in the world in saying something. It’s not like USB is some esoteric option few would consider. Where are the developers who are informing customers of the problem? PS Audio?
Academics and many other engineers claim cables don’t make a difference on theoretical and scientific grounds. Until they listen — with an open mind. The distinction I’m making is between the theoretical and practical applications, about the evidence for the latter in high end gear. I say again, I have no basis yet for an opinion (I’m soon to hopefully find out more). Thus, short of that, as a scientific thinker, I’m looking for corroborating circumstantial evidence of an empirical kind that one would expect to find were USB a common problem, or at least a substantial one, with the level of components discussed in forums like this.
USB isn’t a common problem. I get the idea you feel the problem has to be endemnic to the technology. It isn’t. It is a problem when ground differential is too high and that can be mitigated. It exists because of the ground path DCR.
Claims are meaningless to me. A verbal claim is an unproven hypothesis and the beginning of the scientific process, not the end of the process (a real and unbiased repeatable confirmation). In God we trust all else bring the data.
Analog and digital cables do measure differently in many ways, and all to accepted measurement methods. If someone wants to trial and decide that a cheaper cable is good enough for them…no problem. That doesn’t all of a sudden erase the differences between cables.
Well, while I have been very skeptical of your claims, and a cable maker I checked with also disagreed, I did say that I would try the AQ FMJ noise filter. On a run from an SSD in a Inateck USB 3.0 case to an Oppo 203, I’ve now tried the AQ with two USB cables, the WyWires Diamond and the CAD II-R (I prefer the latter, but then a QSA is coming). With each and the FMJ inline, the sound is clearly better in most every way. Whatever the validity of the claims you’ve laid out, it’s hard to argue with that. I’m told a DDC might even be better. In any case, I thank you for the suggestion.
However, there has been one other drawback in use with the FMJ, especially with the CAD cable. Specifically, loading time is slower with the AQ, very much so with the CAD. With the CAD, the delay is in 1) loading the SSD drive (30-35 seconds), 2) starting music files (many seconds) and 3) playing them smoothly without early momentary pauses (that mainly occurs with the first file played). Without the FMJ, there is little delay with the CAD and little in either condition with the WW. In addition, with the CAD/FMJ combo album cover files load very slowly and often seem to hold up the starting-to-play process, as well as sometimes affect whether the file playing displays on the TV screen, vs. staying at the whole album display.
I’m wondering what might be causing all this. Would it be some kind of USB 2.0 time delay effect? The external difference between the WW and CAD is that the latter’s ground line runs apart from the main line (the SSD picks up power and ground from the Oppo). The CAD also uses an internal filter. Any ideas?
I have not experienced any streaming delay issues with my USB to the T+A DAC that I use or better to say, I have not NOTICED a delay as I generally turn the DAC on and stream continuously so a small delay that might be there isn’t noticeable. I use the JRIVER streaming software on an AMD 5600G PC with a 6 TB Seagate NAS drive.
I also use a “standard” USB cable, not a design with any active components. Have you for information used a totally passive cable? Yours may already be passive but for grins, use a “typical” non audiophile cable and just see about the delay. I’d also check with AQ to see if they have suggestions as to what may be going on.
It may be specific to the kind of run. Like yours, ordinarily the start up time is not something I’d notice beyond perhaps a slight delay, since between turning on five components 30 seconds passes anyway. The difference between the two USB cables really caught my attention when switching cables back and forth or between FMJ and not. The cables are both passive. I asked the CAD cable developer, but it is holidays.
OK on the observations of start-up delay. The Jitterbug FMV could be active as it sees a USB power source and can have handshaking going on. That can cause a delay. The AQ web site doesn’t really say how the FMJ works, passive or active design.
The claims aren’t “claimed” but the actual test data by IGOR’s Labs. If we do have ground current loops, we “may” see a benefit based on how bad the current is to none at all if we don’t have ground loops. The FMV does work to mitigate ground current but the audible DA circuit with no ground current compared to unmitigated is what’s always in question to our ears. The data isn’t questionable though, it is real on that specific measure. Our ears aren’t just the measurements, agreed.