harmonics and single-ended versus balanced audio cables

[GaryProtein]

The run from my preamp to power amps is 50 feet. About 38 feet from the rear diagonal corner with the sources to the center of the room on the opposite side of the room running in the basement to the amplifiers plus about six feet above the floor on each end.

I am using differential balanced XLR cables because they minimize noise gain over the cable run. If you have no noise generating sources near the cables, there shouldn't be any difference between single ended and differential balanced XLR.

 

[opus112]

If you have no noise generating sources near the cables, there shouldn't be any difference between single ended and differential balanced XLR.

This is a fairly commonly believed myth. However the reality is common-mode noise reaches the victim cable by conducted means so physical separation is relatively immaterial.

 

[Folsom]

But it's also dependent on the equipment, as different equipment will reject more, less, or no common-mode noise.

It's easy to forget that factor. Even reading PDF's from cable manufacturers and such, it's easy to point out how much of a fault types of cables may have. But they ignore the differences in electronics and continue on as if they're all totally inept.

 

[Ron Resnick]

Boy, Ron, the use of the apostrophe isn't the only grammatical concept about which you are obsessive.

I'm going to be very careful to never end a sentence with a preposition! ! !

Ooops, I used a split infinitive. Please forgive me!

 

[Ron Resnick]

I suspect that should be ok, the environment isn't very dirty from other electronics and such. And sometime in the near future I'll have a finished product that can be used to reduce the noise picked up down to balanced or lower levels, so that'll become an option. (it exists already, just hasn't been made into the final version)

But I have to say, wow, that's a long run. Mike L's amazing room only takes 28ft~, for example.

My room is only 25 feet long but the preamp is in the room next door. So by the time you add the length from the preamp down to the floor and across into the listening room and over to the other side of the room and up 20 feet to the front wall and over to the amplifier it all adds up to about 45 feet.

 

[JackD201]

Just to remember that sometimes the less is more implies that capacitors in the signal path are an enemy - than input and interstage transformers are used in SETs.

Perhaps, with the exception of coupling capacitors which are far more common between driver and output stage.

 

[Zeotrope]

That's a long IC for unbalanced, if it can be avoided, I'd avoid it. For those lengths the output section of (I'm guessing) your preamp needs to be able to drive long cables, that might rule out some preamps. It would seem almost impossible for a shielded cable that long to not have fairly high capacitance, which will make the sound dull especially if the pre has a higher output impedance. Pro gear is generally designed to drive long cables but tube preamps without follower outputs just can't do it.

The lower the output impedance of the pre-amp the lower the capacitance, is that correct?