Using digital interconnect as analog interconnect

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi:

I am using 75ohm Belden 1695A cable with BNC termination as my analog interconnects.

What are the pros and cons of using a 75ohm double shielded (foil and braid) cable as analog interconnect between preamplifier and amplifier?

It sound fine but technically how does coaxial and twisted pair (both shielded) compare as analog interconnect?

Thanks
 
By analog interconnect I assume you mean for normal audio signals. Coax and twisted pair both work fine for signals from DC up to high MHz/low GHz, depending on length and dielectric. BNC should be OK for audio, although its constant impedance characteristic will be completely irrelevant.

Pro of your choice is that it will work OK. Con is that something cheaper will probably work just as well.
 
Hi:

I am using 75ohm Belden 1695A cable with BNC termination as my analog interconnects.

What are the pros and cons of using a 75ohm double shielded (foil and braid) cable as analog interconnect between preamplifier and amplifier?

It sound fine but technically how does coaxial and twisted pair (both shielded) compare as analog interconnect?

Thanks

What DF96 said.The place were that cable makes an improvement is replacing you turntable cable with it not with the BNC end tho. There a better (lower pF) cables than the Belken ... Petra is one.

Cheers,
Bob
 
Administrator
Joined 2004
Paid Member
Analog signal thru a digital interconnect? Oh no - That will tear your signal to bits!

Sorry, couldn't resist. :D

I use Belden and Canare coax often enough for AF. Works fine. But my question is, what gear do you have that uses BNC connectors for audio? Did you build it yourself?
 
quality coax (such as belden 1694A) with bnc is really very good for audio imo, the late Erno Borbely used it on his preamps and amps including termination resistors. I more often use twisted pair for differential signals, but for single ended coax is very good imo
 
Termination resistors? For the coax impedance at 100Hz, 1kHz or 10kHz - all different. Coax at audio frequencies does not behave quite like coax at RF, so you can't terminate it in the same way.

Coax cable should not sound either bad or good, it should not sound at all. Exception is if you have a very long length - 100's of metres, or drive it badly from a high impedance.
 
Thank you all for so many responses.

I actually had that cable in hand for digital use. I just wanted to experiment thus I took out the RCAs and installed BNC bulkheads on pre/amp. I didn't hear any difference, must be my non-golden ears. I did like the secure connection offered by BNC and solidity of Belden.

Other day I was on audiophile cable manufacturers' websites and saw space age designs for single-ended signal. Thus now, I am seeking technical difference of using coaxial or twisted pair for analog signal.
 
Could that be because the Signal Return is not shielded?
The Signal Flow is shielded.
The difference in voltage between the Signal Flow and the Signal Return at the Receiver input is amplified to be sent on to the next stage.
If the Signal Return is subject to interference such that that voltage difference signal is adversely affected then the amplifier is being fed with a "bad" signal and cannot send on a "good" copy to the next stage.
 
............. a screened twisted pair would have the same problem.
I am not sure that is the case.

The twisted pair is immune to the external field due to the screening and due to the close coupled twisted nature of the Flow and Return.
Ground current could be directed along the screen if needed or it can be single end connected as screen only.
The amplifier sees the voltage difference at the receive end of the Flow and Return pair.
I don't think that can be said for a Coax, which must have the screen connected at both ends.
 
Assuming no hum loops, the receiving end sees the difference between signal and return for both cases. The twisted pair is still subject to magnetic fields, and relies on cancellation - the screen is likely to be too thin to stop an audio frequency magnetic field. The twisted pair relies on twisting, the coax relies on cylindrical symmetry. There is a small advantage to the twisted pair if the screen is poor - you can still get cancellation if you have a differential input, even if an external electric field induces a signal. This may mean that a cheap twisted pair is better than a cheap coax.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.