Tír Na HiFi

nige2000 wrote:

jkeny wrote:I was wrong above - I read it stated on equipment that 720Mhz is greater than the speed needed to pass the 3rd harmonic of hi-speed USB signal & not GHz as I said.

do you know the calculation for impedance, (lenght, diameter) i might experiment

I don't think it's that easy to calculate as it's the characteristic impedance we are talking about i.e the resistance that the cable represents at the frequency of the transmitted signal. http://en.wikipedia.org/wiki/Characteristic_impedance

I think the easiest way to assess the characteristic impedance goes something like this - use a scope & signal generator - send a signal of the desired frequency (? not sure what MHz this should be for the 3rd harmonic of 480Mbps) down the signal wires & measure the voltage at the far end of wire - then using a 45ohm resistor connected to ground at the far end of each wire, measure the new voltage - if the characteristic impedance between the wires is 90 ohm (45 ohm to ground for each wire) then the voltage will be halved.

So not an easy spec to satisfy

jkeny wrote:

nige2000 wrote:

jkeny wrote:I was wrong above - I read it stated on equipment that 720Mhz is greater than the speed needed to pass the 3rd harmonic of hi-speed USB signal & not GHz as I said.

do you know the calculation for impedance, (lenght, diameter) i might experiment

I don't think it's that easy to calculate as it's the characteristic impedance we are talking about i.e the resistance that the cable represents at the frequency of the transmitted signal. http://en.wikipedia.org/wiki/Characteristic_impedance

I think the easiest way to assess the characteristic impedance goes something like this - use a scope & signal generator - send a signal of the desired frequency (? not sure what MHz this should be for the 3rd harmonic of 480Mbps) down the signal wires & measure the voltage at the far end of wire - then using a 45ohm resistor connected to ground at the far end of each wire, measure the new voltage - if the characteristic impedance between the wires is 90 ohm (45 ohm to ground for each wire) then the voltage will be halved.

So not an easy spec to satisfy

ok will read

was hoping for a/b=c sort of thing
but i think ill stick to winging it.

I have a frequency generator and a scope - but I don't think my freq generator goes that high, I think it only goes to abut 100kHz.

tony wrote: Got my Nigecat USB cable in the post this morning and what a surprise. Out of the package I can already see that this cable is going to make a difference.

Positive expectation. And of course it sounded good.

If it had looked rubbish you would have thought the opposite.

Negative expectation. Would have sounded bad.

The actual sound quality would have been identical regardless.

You listened to your expectations, not the cable.

maxflinn wrote:

tony wrote: Got my Nigecat USB cable in the post this morning and what a surprise. Out of the package I can already see that this cable is going to make a difference.

Positive expectation. And of course it sounded good.

If it had looked rubbish you would have thought the opposite.

Negative expectation. Would have sounded bad.

The actual sound quality would have been identical regardless.

You listened to your expectations, not the cable.

Now, Tony, bet that's flummoxed you?

Jaysus, even I got that Tony was messing!

Really!?

<Chuckle>

Your humour is too subtle, Tony. We need more pie-in-the-face stuff.

Diapason wrote:<Chuckle>

Your humour is too subtle, Tony. We need more pie-in-the-face stuff.

Tony, subtle? You jest!

"I have already done a double blind test by putting my current selection of usb cables on the table and each time I picked the NCat."

This tickled my fancy, could have come straight from Neil Gader et al over at TAS

With regard to expectation bias Max has exceeded expectations. A perfect example that maybe expectation bias can be very useful and intuitive.
Expectation bias from me would be Max would come out with exactly that type of comment. Eureka!

Briefly tried Nigel's cable this morning. It works! Will have a listen over the weekend comparing it to the TZ Pang cable.
BTW Max I am not particularly a usb cable believer and don't think they have a huge influence. But I am prepared to listen to people's
view and give it a go.

belated happy new year Max.