Where is the empirical evidence of improvement using balanced
connections? Any? Any at all? Oh, that's right, because there is
none.
Actually there is and its historical. So here is the history: Before balanced lines were developed, a long distance phone call was really only good to the other side of nearly any given state, and you had to be prepared to yell at the top of your voice to be heard. When balanced lines were introduced, this made transcontinental phone calls possible with greater intelligibility. The recording industry was quick to adapt the technology (in the late 1940s and this is one of the key technologies besides the invention of the tape recorder that ushered in the age of high fidelity.
The whole point of balanced cable operation is to avoid interconnect
cable interaction with the sound of the system and if the tenants of the
balanced system are followed, it does this very well. This means that
to sound right, the cable does not have to be expensive, it simply has
to be correct!
Could you clarify this, because in my
mind, the point of balanced is, and has always been common mode noise
rejection. Good cable construction will of course lead to consistency
of noise on both cables ensuring common mode rejection.
Now
w.r.t. studio balanced connections, i.e. AES compliant, that is not just
about balanced, but a drive/load standard that is low enough impedance
to dominate over cable parameters.
Sure. As you can see from its historic legacy, balanced lines were used to increase intelligibility. This is exactly why it made it possible to hang a pair of microphones above an orchestra, and have the tape machine 150 feet away, receiving that mic signal without degradation. Certainly noise rejection is one aspect, but so is the rejection of ground loops (that is why the balanced line system ignores ground).
No, that statement is quite true. A floating source is not the same as a
differential source. It would only be truly differential if you center
tapped it and connected the shield to the center tap, such that coupling
to the cable shield is similar for both conductors. That is not the
case for a cartridge.
This statement is a common myth, and being a myth, is false. A center tap degrades the Common Mode Rejection Ratio, on account of the simple fact that no center tap is really centered exactly. For this reason, center taps are never used. This is true of dynamic mics, cartridges, tape heads and any other inductive source including input and output line transformers.
And than, we gonna “hear “the difference between the 2: for me RCA is
more open: good balance, beautiful placement , detailed and holographic.
XLR: gives also a good balance, placement:okay, but the openness is
less: “flatter” compared to RCA. Conclusion: I only used RCA. ( my
system: CEC cd-player, Auralic streamer, Metronome Technologie C6 (dac),
Daniël Hertz M6L ( préamp) Wavac MD 805 m ( monoblocks) and Ilumnia
Magister (speakers)
The problem here is that in order to obtain the benefit of balanced operation, your equipment must support the standard, AES48. Having introduced balanced line operation to high end audio, I can tell you that hardly any high end audio gear supports the standard and so you hear differences, and often degradation. That's a unfortunate because the technology clearly works (which is why all your recordings use it); you'd think audiophiles would be interested in something that prevents interconnect cables from interacting with their audio system. If you've ever heard differences between cables you know what I'm talking about. Imagine all the cables sounding as good as the best you've heard: that is the benefit.
I think I would be a great idea to ask the the great phono cartridge and
phono amp designers to clear this up - hopefully they might all agree.
Question: precisely how are cartridge and turntable wired to the phono
amp to obtain fully balanced operation?
The first balanced line phono section was made by Atma-Sphere Music Systems in 1988 and offered in the first balanced line preamp in 1989. Since the cartridge is already a balanced source, its a matter of getting the signal to the preamp without involving that signal with the ground system (the tonearm tube and turntable). To this end, the plus and minus outputs of the cartridge are tied to pins 2 and 3 of the XLR connection. The tonearm ground then becomes the shield of the interconnect cable and ties to pin 1 of the XLR at the phono input. Since the phono input is balanced, it ignores ground and looks at what is different between pins 2 and 3. In other words, the signal is **received** in the differential domain. In the old days this was done with an input transformer with its primary winding simply tied to pins 2 and 3; the ground is simply the chassis of the preamp. Of course you don't need the transformer, but then you need a differential amplifier at the input of the phono circuit. This can be done with tubes or transistors. This is how our phono preamps work and the signal is kept in the differential domain throughout the preamp.
The tricky bit is that sometimes the tonearm manufacturer does not supply the arm with a removable interconnect cable. But most do, and usually if they don't (Rega comes to mind) it is possible to convert the arm anyway. Back in the old days, turntables like BSR, Dual, Garrard and so on had the tonearm wires exit the arm beneath the plinth where there was a terminal strip that had connections for the 4 cartridge wires plus the tonearm ground. That was where the interconnect cable was attached, so even for those ancient machines its fairly easy to install a balanced line simply by replacing the interconnect cable.
