The "Wire we Here?" Blog and Forum
A place for ICONOCLAST RCA discussions
If you are using the BAV RCA for a digital output, it is a ~ 110 ohm cable designed for analog. The 4694P is a true 75-ohm RF serial digital cable and is better matched to the expected load that is a 75-ohm resistor. The cable to load has lower RL reflections than the BAV. Technically yes, the 4694P is a better cable for DIGITAL where the BAV is the better cable for ANALOG. We don’t try to mix the two applications but optimize to the expected load. The proper resistive load for RF is matchiung to the cable impedance =SQT(L/C). There is no phase angle at RF as it cancels out. Thus the cable is a pure resistive vector at RF. We can use a high tolerance resistor matching the cable impedance. Analog isn’t like this…read on. On shorter digital runs, where the RL reflections can be high, the best resistive load match is important. Longer improper cable impedance (too low 50-ohm or too high 110 ohm) cable lengths attenuate the RL reflections more for moderate distance runs but as you get longer, those RL reflections are a form of attenuation and will limit the maximum reach (less signal voltage) to a lesser distance. On a shorter run with improper cable (110-ohm analog), RL reflections are pretty severe and can swamp the error correction. Analog cable does not need the extreme geometry as digital and we can use AIR TUBE design (the BAV) to lower capacitance as analog IC cable is a voltage transfer function into a high impedance 47-kohm load (not a 75-ohm resistor like RF, big difference) with analog wavelengths that are far, far in excess of the cable length so the RL reflections aren’t a thing for analog cable. Using the proper 75-ohm cable will allow optimum use from the shortest to the longest runs because the RL reflection losses are removed and the signal strength is maintained over longer runs. Shorter 75-ohm runs also see far less RL signal bounce and the error correction can be less impacted.
If you are using the BAV RCA for a digital output, it is a ~ 110 ohm cable designed for analog. The 4694P is a true 75-ohm RF serial digital cable and is better matched to the expected load that is a 75-ohm resistor. The cable to load has lower RL reflections than the BAV. Technically yes, the 4694P is a better cable for DIGITAL where the BAV is the better cable for ANALOG. We don’t try to mix the two applications but optimize to the expected load.
The proper resistive load for RF is matchiung to the cable impedance =SQT(L/C). There is no phase angle at RF as it cancels out. Thus the cable is a pure resistive vector at RF. We can use a high tolerance resistor matching the cable impedance. Analog isn’t like this…read on.
On shorter digital runs, where the RL reflections can be high, the best resistive load match is important. Longer improper cable impedance (too low 50-ohm or too high 110 ohm) cable lengths attenuate the RL reflections more for moderate distance runs but as you get longer, those RL reflections are a form of attenuation and will limit the maximum reach (less signal voltage) to a lesser distance. On a shorter run with improper cable (110-ohm analog), RL reflections are pretty severe and can swamp the error correction.
Analog cable does not need the extreme geometry as digital and we can use AIR TUBE design (the BAV) to lower capacitance as analog IC cable is a voltage transfer function into a high impedance 47-kohm load (not a 75-ohm resistor like RF, big difference) with analog wavelengths that are far, far in excess of the cable length so the RL reflections aren’t a thing for analog cable.
Using the proper 75-ohm cable will allow optimum use from the shortest to the longest runs because the RL reflection losses are removed and the signal strength is maintained over longer runs. Shorter 75-ohm runs also see far less RL signal bounce and the error correction can be less impacted.
In various forums I was led to understand that if you do not have a hum problem, RCA interconnects up to 3-5 feet are fine, and may even have an advantage over balanced - provided they are not too long.
@jeffreyinphila Hi Jeffrey, looks like we've been sleeping again. Yes, unless the additional shielding provided by a balanced/XLR cable is needed, the single ended RCA in short runs is considered to many to be a better sounding option. This will of course always be debated. Hope you are well.
@jeffreyinphila
Here is the analysis on RCA and XLR. The RCA has ONE and only ONE reference to a ground for the signal. There can be no "unbalance". This means ths signal is as undistorted voltage as possible.
An XLR has a measured Capacitance UnBalance or CUB for short hand. We have TWO sources referenced to ground. The two ideally equal and opposite voltages aren't really 100% equal due to geometric changes that alter the signal to the reference ground and capacitance and this by default alters the voltage signal.
But, if NOISE is a big issue a signal that is SLIGHTLY imperfect is far, far better than one full of noise. On long runs, or where noise just can't be tolerated or, pun intended, run to ground XLR are the best option. A signal superimposed with noise isn't anybody's buddy no matter how pure the signal voltage.
Now to toss in another variable, the op-amps or transformers used for XLR are also in the signal path and can alter the signal and sound. Balanced systems are pretty good but they are more complex than the RCA's input/output system.
In a home situation with shorter runs and a better controlled electrical "grid" of wires, the RCA is the best signal cable there is. If you don't have noise, RCA are best.
Galen
Thank you Galen and Bob.
In homes where the run time is short and the wire "grid" is well controlled, the RCA is the best signal cable. RCA is best if you don't have noise.
If I'm not mistaken, you've opened up another polarizing cable issue that enthusiasts are happy to argue.
Premise: If there is only 3-5 feet of line between the components, no noise, and no "rat nests" of overlapping cables, then the RCA interconnect is likely to be "better" than the XLR interconnect. Cause: There are no op amps or transformers and no additional internal connections in the signal path inside the component.
Audiophiles always ask me what XLR interconnect I use. I explained (somewhat defensively) that I had RCA. They quietly listen to the reason (no noise, only 3-5 feet long). When they decide how to respond, they always get a similar look on their faces. They either nodded politely and tried not to shake their heads from side to side, or they were not so polite and firm in suggesting that I consider XLR as my next upgrade.
Based on what you wrote in your reply above, RCA interconnects are not only as good as XLR, but most likely better than XLR. I don't think most audiophiles know anything about it.
Galen, am I getting it right?
-Jeffrey in Philadelphia (Delighted owner of Iconoclast Series 2 TPC spkr. cables.)