[mshan]

Based on readings in this forums or personal observation, has anyone determined if there is an optimal length for the Blue Jeans Cables digital coax cable and also their AES /EBU cable?

If so, what is it and what sonic degradations have been observed at shorter than / longer than optimal lengths?

Also, anyone know how this Mogami Neglex AES/EBU cable compares to the BlueJeansCables Belden AES/EBU cable (sonically and in terms of tip to tip 110 Ohm impedance)?

 

[replytoken]

FWIW, you may want to ask the folks at Blue Jeans their opinion. They were helpful when I placed my order for IC's. I am sure you will get differing opinions from folks, but you may want to add theirs to the mix before you make a final decision.

 

[mshan]

Good idea; just did that!

Any idea how the Mogami 3080 stacks up again the Belden 1800F, both as an AES/EBU digital cable with Neutrik XLRs?

 

[ooheadsoo]

Consensus of the engineers at diyaudio seem to say that the longer the better, about 10+ feet as a rule of thumb minimum. The reason is that reflections from impedance mismatches will be delayed by the length of the cable enough that the receiver will discount it as a...reflection.

 

[mshan]

Did they comment on specific sonic degradations with less than 10 ft lengths (5 feet seems convenient)?

Also, anyone on that forum commented on the sonic differences between Mogami 3080 and Belden 1800F?

 

[ooheadsoo]

Sonic? No, they're engineers. Technical? Yeah. In a word: jitter.

 

[mshan]

Blue Jeans Cables got back to me really fast!:

"No, there's no optimal length.

The impedance can't be maintained at 110 ohms through the connector in any
XLR because of the wide spread of the XLR pins.

I haven't tried the Mogami; the biggest issue for AES/EBU would be impedance
tolerance, and my guess would be that there's very little difference."

 

[ooheadsoo]

The only connectors that are up to spec for any standard is bnc and f for consumer grade. I don't know why it's that way, but they're the only connectors made at 75ohm impedance. Given that impedance continuity can't be maintained, there will be reflections, so...

 

[slwiser]

mshan

Did you look into getting the AES/EBU breakout cable that comes with the RME Digi96 PAD version? Would the AES/EBU XLR connection breakout cable not connect directly with your external DAC?

Or do you suggest getting only the RME Digi96 soundcard that does not come with a cable?

Quote:

Originally Posted by mshan Did they comment on specific sonic degradations with less than 10 ft lengths (5 feet seems convenient)? Also, anyone on that forum commented on the sonic differences between Mogami 3080 and Belden 1800F?

 

[braillediver]

WBT Nextgen connectors are supposed to be tru 75 ohm connectors.

A little pricey but they are more resiliant \ stronger than the Eichman's and they take the punishment of soldering better.


Since I don't know anything about the subject I feel qualified to comment- When I worked with microwave cables 2Ghz to 12Ghz Frequency range- real short cables can have very high levels of reflected energy. A longer cable will attenuate \ reduce the reflected energy.


Loss in the cable was the amount of energy injected into the cable (S1) compared to the amount of energy received at the end of the cable (S2) in db- so that is S12.

Standing wave ratio was the amount of energy injected into the cable (S1) compared to the amount of energy reflected back from the end of cable measured at the input (S1) in db- so that is S11.

These measurements are also taken at the end of the cable = S21, S22 so you know the loss and reflection in both directions. The measurements are not equal in both directions- you can have a higher loss in one direction than the other.

Proper impedance matching reduces reflections and reduces the amount of loss in the cable. Reduced reflections means the source isn’t being bombarded with energy which it’s not designed to receive.


Yeah something like that. I’d probably be inclined to use a longer cable than a shorter on.

And thinking about the assembly of microwave cables- it’s consistency in the construction that reduces inductance and capacitance variations along it’s length which effect the cables impedance which effects the cables Standing Wave Ratio = reflected energy.

Pretty much you wanted the size of the conductor uniform through it’s entire length, the connections uniform, the distance between the conductor and the shield uniform- this changes the cables inductance and capacitance at that specific point which effects the reflected energy. We tuned the conductor diameter and pin diameter to better match the cables at transition points.


This unqualified rambling is brought to you by Mitch.

 

[mshan]

No, I haven't tracked down an used AES/EBU breakout cable yet (new ones are almost $40).

From what I've read, it's supposed to be the best option with the RME, but that may also depend on the dac you choose to use (e.g. Benchmark DAC1, I think, i s supposed to essentially sound the same irrespective of which connection you use).

 

[slwiser]

mshan

I have on order a RME Digi96/8 PAD with the AES/EBU breakout cables.

Should be coming in, in about a week or so.

Thanks

Quote:

Originally Posted by mshan No, I haven't tracked down an used AES/EBU breakout cable yet (new ones are almost $40). From what I've read, it's supposed to be the best option with the RME, but that may also depend on the dac you choose to use (e.g. Benchmark DAC1, I think, i s supposed to essentially sound the same irrespective of which connection you use).

 

[darkless]

Quote:

Originally Posted by slwiser mshan I have on order a RME Digi96/8 PAD with the AES/EBU breakout cables. Should be coming in, in about a week or so. Thanks

Be sure to let us know if you're able to detect any differences w. regards to comparing the RME AES/EBU connection and the iRiver optical connection when fed to your DA10