How will XLR cables vs RCA effect a phono pre

Okay maybe this is just silly or I am!...

First off XLR from the "CARTRIDGE TO PHONO amp" Is almost pointless... All cartrides have 4 pins, and they are naturally already considered a Stereo left right a balanced source..RCA jacks from the Cartridge to your phono will probably in most cases as long as its shielded make little to zero difference, same noise from the cart will enter your phono stage even if it was XLR from my understanding, I mean its passive circuitry nothing is active in your cartridge or arm to those jacks whether being RCA or XLR.

Secondly
XLR from Cartridge to Phono AMP will not GIVE you 6 db more gain, that cartridges is still a passive device and nothing is amplified more at that point... However XLR from the PHONO AMP to the Preamp could up another 6 db as thats the nature of the balanced active circuit.

Anyway I see virtually no reason that on paper the XLR which 99% of turntables do not have will make the passive cartridge sound better... Or quieter.. Now the only advantage to XLR would be having a Phono amp OUTPUT XLR to a Good Fully balanced PREAMP from its active gain circuits... And even then it seems very little can be had in most systems unless you really have the equipment to get that 5% degree of difference or because you have your Turntable VERY far away from your System and have the phono amp hooked up very close to the turntable(good idea) with cables only 2 or 3 feet away and then need to drive an XLR cable 20 feet to your preamp or something, THEN I can see XLR playing a critical part in this configuration, but only on the Phono AMps output, not on the cartridge passively sitting on your arm feeding that tiny signal to your phono amp if that makes sense..

Maybe I am just not seeing any benefit to a XLR input on a phono amp, but I do see it being beneficial in some cases on the output of the phono amp after active circuitry has been applied to the signal.

If not Enlighten me please!

Undertow: Ralph Karsten has talked about this in detail on another thread here:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1171733027&openusid&zzAtmasphere&4&5#Atmasphere

I'm not particularly technically minded so much of it is beyond me, but after using a fully balanced phono stage I would never use anything but.

Noise is always an issue in phono reproduction. Anything you can do to reduce it is helpful, as long as those techniques do not introduce other problems.

Balanced operation is on of those techniques that works. You get reduced noise in 2 ways:
1) reduced noise from the cable and its routing
2) reduced noise from the phono section.

Differential gain stages have theoretically 6db less noise than the equivalent circuit operated single-ended, after you have accounted for gain differences. The noise of any phono section is compounded from gain stage to gain stage; so if the phono section is fully differential from input to output the reduced amount of noise can be substantial- perhaps 12 or 18 db in theory.

In fact in practice the actual reduction in noise is less, but only by a db or so if you have good design. This phenomena is so pronounced that in our phono section we are able to get sufficient gain with only 2 gain stages- despite the fact that our EQ is passive. With less gain stages there is less places for things to go wrong.

The fact of the matter is that going balanced, fully balanced, offers a very nice upgrade to phono performance. If the preamp is not balanced then IMO there is only marginal advantage to using a balanced cable.

Atmasphere"If the preamp is not balanced then IMO there is only marginal advantage to using a balanced cable. "

I agree.. SO the big question is.... Are we talking about a BALANCED design so to speak which seems to me to be the same on the end of the turntable anyway being its RCA Jacked, or XLR Jacked... Or are we confusing that everyone must Modify their turntable to Wire it VIA XLR?

I mean it kinda seems to me that from the Cartridge to Phono amp there is not really any wiring difference to do here in order to go XLR, and most tables will have to be modified connecting that extra wire, but to what inside the arm? Or simply just shorting pins 1 & 3 to simply interface the input circuit on a "Balanced" phono stage.. Which simply to me would mean you can still have a standard wired RCA style turntable, and just short RCA ground via an XLR adaptor or something to your existing RCA JACK in order to keep everybody from running out and re-wiring (somewhat expensively) their arm and adding XLR jacks to the back of a turntable.

Anyway due to the subject matter I am simply trying to establish a ground point here that its possible you don't need an XLR equipt and wired turntable to acheive the connection at a (Fully balanced) Phono stage.

Hi Undertow, you do **not** have to modify the tone arm. Most arms are already set up as balanced sources, even the lowly BSRs, Garrards and Duals of yesteryear.

You do have to jump through some hurdles with the air-bearing straight tracking arms, as they have so many lateral tracking mass problems that the designers usually eliminate the 5th wire that is common to all other arms.

The 5th wire is the ground, and is why the arm needs no mods.

The cartridge outputs are the twisted pair that runs inside the balanced line. The 5th wire, ground, is the shield of the cable, and ties to pin 1 of the XLR. So the shields of the cables are both tied to the same point at the arm end of the cable (ground).

Note that in this hookup scenario, there is no signal on the shield. So the arm itself shields the signal from the cartridge, and once through the bearing system, the interconnect cable takes over the shielding from there.

If the cable passes through a noise source, the noise will be impinged on both plus and minus signals in the same way, and rejected once arriving at the preamp input. In this way noise is reduced. In a single-ended system this noise would be amplified by the phono preamp.