Just retired and want to get back to vinyl listening

interesting discussion,,,,,,,,,  I see some phono preamp-stage -- have "balance controls" that say this is for adjust issue of balance on the cartridge  -- I expect this is something different -- but the education continues  ;-)

fsonicsmith

OK, you will have to explain this one to me. Many turntable manufacturers offer DIN outputs but you are obviously saying that those that only offer RCA outputs (like VPI's for example) are actually balanced. IMHO, you won't find too many phono stages that offer balanced operation

Most phono cartridges are inherently balanced; they have separate left, right, grounds and shield. There are many fine, truly balanced phono stages, such as Audio Research, and a good argument can be made that the phono section is the most beneficial place in a system to use balanced operation.

Most phono cartridges are inherently balanced; they have separate left, right, grounds and shield. There are many fine, truly balanced phono stages, such as Audio Research, and a good argument can be made that the phono section is the most beneficial place in a system to use balanced operation. 

Yes, I have read, heard, and known for some time that phono cartridges with their four pins are true balanced. That is not the issue I am asking you to address. I am instead asking you how RCA outputs from a typical modern table can be used in balanced form as you clearly stated. 

fsonicsmith

Yes, I have read, heard, and known for some time that phono cartridges with their four pins are true balanced. That is not the issue I am asking you to address. I am instead asking you how RCA outputs from a typical modern table can be used in balanced form as you clearly stated.

That depends on the balanced phono preamp’s inputs. If it uses RCA connectors - such as ARC - then all you need is a pair of RCA cables. (You may or may not choose to also use the separate shield.) If the inputs are on XLR connectors, then you’d obviously need to use XLR connectors on the phono preamp end and whatever else you need on the pickup arm arm end, be it DIN-to-XLR, or RCA-to-XLR. Or you can get a pickup arm breakout box that terminates in XLR connectors or whatever connector of your choosing.

curious as to why more TT/tonearms would not have balance outputs and equipment inputs for these in various equipment be the xlr balanced inputs

The idea of the cartridge being a balanced source was introduced to home audio in 1989 by Atma-Sphere (the MP-1 was the first balanced line preamp for home use). Before that it just wasn't around. To this day, I still occasionally run into tone arm manufacturers that don't realize that the cartridge (and thus the tone arm) is a balanced source. If we're talking about inexpensive gear that uses OPamps, its almost the same cost to run balanced as it is single-ended. But the industry relies heavily on tradition- meaning that it will try to do the same thing the same way decades on after its been shown that there is a better way. In that regard audio is like a host of other industries- and maybe that's just a human nature thing. 

I am instead asking you how RCA outputs from a typical modern table can be used in balanced form as you clearly stated.

This is sort of a cringe-worthy thing that you sometimes run across. The idea is that the RCA connection is not tied to ground- usually they 'float' and if tied to ground, are done so by a wire. But you could use the ground side as the minus output of the cartridge, and so- you could then have the input circuit be a differential amplifier and *if* the ground wire is tied to chassis it would work. Sort of- you do have this little problem that the '+' output of the cartridge is likely going to be shielded by the '-' output of the cartridge (by the single-ended tone arm cable), and this is where the cringe-worthy issue comes up- this leaves the system highly vulnerable to hum. Now if the cable was built balanced, and the shield was actually the ground wire, then the only area where the system is hum susceptible is the RCA connector itself.

I think this idea got going so that the preamp would be instantly compatible with any turntable interconnect, but in reality it isn't. On top of that, as soon as the minus output is acting as a shield for the plus output, the construction of the cable is going to have an effect on the sound, so you just lost an important aspect of balanced operation, which is cable artifact immunity. IOW it really should be done with an XLR.