Ah! That reminds me that gold plated pins on a 13 amp socket, definitely improve the audio from good analogue audio amplifiers!

Andrew.

Edited By Andrew Tinsley on 26/02/2021 20:16:09

I think that someone has (apparently) been pulling your plonker.

IFF the bits are getting transmitted and received correctly the quality of the cable will make absolutely no difference.

Unless you are sending signals over too long a distance or in a high noise environment the chances are that a cheap cable should be fine (subject to correct manufacture).

Be wary of advice from hobby mags on these matters – particularly when talking about hi-fi – kit reviewers and bloggers have to maintain interest and hence sales; one of the ways they do this is by cooking up fashions for one expensive tweak or another. Remember when sounds weren't worth listening to unless your speakers were hooked up with cable capable of serving the National Grid – but with five million cores!

Hmmm, not an electronics engineer I presume? Electrons most definitely are fussy, and can be extremely annoying when they don't flow where you expect.

The USB signal (1.x and 2.0) is differential, transmitted over a twisted pair with a nominal impedance of 90 ohms. If the impedance is wrong and/or the lines are not terminated properly then reflections and overshoots will occur, ultimately leading to loss of signal integrity.

A digital signal is really an analogue signal. In some ways digital is more challenging than analogue as the fast edges imply a larger bandwidth than might be suggested by the data rate. If the transmission channel is not linear, ie, non-dispersive, then distortion of the signal will result leading to problems in decoding the signal. There's a vast literature available on the transmission and decoding of digital signals, with some pretty hairy mathematics.

Having said the above a quality USB cable will not be expensive. The cables linked to in the OP are nothing to do with technical ability; they're intended to separate fools and their money.

Andrew

A digital signal is most definitely NOT an analogue signal. Over copper it is transmitted by way of an underlying analogue signal, but that is a different matter and the two signals are quite discreet.

USB doesn't provide any error correction itself so maybe a bad connection due to an unshielded cable in an electrically noisy environment or wobbly plugs could corrupt the digital stream.

I don't know what hi fi systems do, but computers send and receive data in check-summed blocks and usually ask for repeats until they get clean data. Broadcast digital tv and radio can't ask for a repeat so they just drop the offending block causing audio to go silent or the screen to pixelate. The quality of received segments is perfect, but they are interspersed by obvious glitches. Unlike an analogue system It either works or it doesn't: there is no general low-level loss of quality, just good and bad blocks.

Maybe hifi systems use usb cables as ordinary audio connectors and aren't digital at all. A convenient bodge, but prone to analogue defects, that might be reduced by a decent cable.

What's needed is a good dose of double-blind testing. For some strange reason it's never done…

Dave

I have to agree with Andrew in this one. The signal is analog. The signal is interpreted as digital by the receiver circuit defined by it's threshold levels. Digital coding, analog transmission. You could transmit digitally by sending single electrons with the data coded in spin up or spin down but the cost of your system would make the USB cables above seem cheap.

regards Martin

Yes, I just spent $1,000 on a new sound system. Then realised the sound is only going to be as good as my two hearing aids!

Oh well, at least it's loud enough that I can't hear my neighbour banging on my door, or his bloody dog barking.

Yep that's me. Can't hear the beeper on the microwave any more or the "lights on" alarm beeper when getting out of the car. Shoulda worn earplugs in all those power stations I guess. Let alone Harleys with straight pipes and Nortons with megaphone mufflers. But that would have been uncool.

Martin Kyte: you may well agree with Andrew Johnston on this one but you would, with respect, both still bee wrong.

This really is DigComms 101 – kids' stuff. To say that a digital signal is really an analogue one because it is carried over an analogue channel is as ridiculous as saying that an analogue signal is really a piece of wire because the piece of wire carries the electrons. I've tried to think up an illustrative analogy with the difference between the meaning of word and a dumb spell-checker for you further amusement – but it proved to be too contrived.

Bit of a sting there James however it's read.

Emgee

A digital signal is an analogue signal with only two or three levels. That is why it is called a digital signal. (Yes, if zero is a level, and it is, then digital signals can have three levels, but they are still digital signals.)