Balanced or single ended phono stage?

One thing to remember - slapping XLR connectors on the end of a RCA tonearm cable does not (generally) magically transform it into a balanced cable. And RCA cable (generally) contains 2 conductors: (+) and ground (usually a shield). A balanced cabled contains 3 conductors: (+), (-), and ground (a shield). If you put an XLR connector on an unbalanced cable, the ground (usually a shield) carries the (-) component of the balanced signal. What else gets carried on that conductor? All the EMI that was sent to ground in the unbalanced configuration. Often, you'll need to run your balanced phono pre in an unbalanced mode to shunt that noise. Therefore, if you can't run a fully-balanced cable from your tonearm to your phono stage, you may not be able to realize all the value of the balanced circuitry.

Dave, no worries. It was several years ago. Let me back up a bit.

I had a VPI Aries II TT when I picked up the Ayre P-5x. I did indeed order a custom made phono cable that was configured per the Ayre link you provided. The RCA end plugged into the RCA termination block on the Aries and the other end had XLR connectors for the Ayre phono. Worked well. I still have the 1/2 meter cables.

I don't think VPI had a XLR term block at that time.

I then picked up a used Triplanar VII which had single ended RCA connectors on the built in phono cable. After a while I realized that I had never flipped the bal/se switches to the single ended position! When I did it sounded a tad worse so I left them in the balanced position.

No doubt the change in gain made it hard to compare.

I later converted the Triplanar phono cable to have XLR connectors thinking it might be better. Again I did not notice anything after that process.

Curious, I pinged Ayre's Charles Hansen on Audio Asylum and asked him what was going on. It was a while ago but iirc he said with the switches in the "bal" position the negative or inverted part of the RCA input used of course for unbalanced inputs was allowed to float thus the inverted signal from the cartridge made it to the inverted input of the diff amp.

Not the best way, but as long as the inverted signal in the cable is allowed to float, never grounded, it works because of his design.

I did a quick search on the Asylum to try and find the thread but could not locate it. The search has some quirks to it and I will spend some more time tomorrow watching football.

Might be quicker to repost on the Asylum.

Hope that helps.

I too have heard that balanced is the way to go for a turntable source. When I recently switched from a good to moderate RCA to XLR cable outputing my phonostage, the XLR was clearly better.

This is gpoing to show my ignorance, but if the Phono cable has RCA not XLR connections. Does that not undo the benefit of XLR outs from the phonostage?

Some pretty basic reality:

1. There are many reasons for the quality of sound of a phono stage, differential design being one of many. Balanced might be beneficial, but many non-balanced phono stages beat balanced phono stages. This single factor certainly is not the most critical determinant.

I don't sell, make, or endorse any phono stage makers, I have absolutely no commercial or personal bias. I own both balanced and unbalanced phono stages.

2. Differential circuitry certainly does not eliminate cable influence.

* An inappropriate impedance will still be just as deleterious to the sound.

* A cable design that rings will still ring. And this sounds horrible, balanced or not.

* A cable with leading edge overshoot will still have it. And this too sounds horrible, balanced or not.

* A cable with changing impedance relative to frequency will still have phase distortion, balanced or not.

* A cable that rounds transients will still round those transients, balanced or not.

Balanced design does not change any of the above at all.

Years of interface design experience in high tech, outside of audio, is my background for this statement. In the audio field technical testing and listening confirm this.

Kiddman is 100% correct, but a preamble is really necessary to give his response context (as his truths apply to all circuits and cables).

There is rhyme and reason to cable design and geometry. This simple statement could spawn myriad tangents to this discussion, but as it relates to differential balanced circuits, ONE of the benefits of a properly-designed balanced cable is noise rejection.

Now, you can take any 3 pieces of conductor and connect the (+), (-), and ground and it will "work". But you ideally want the (+) and (-) conductors to be arranged symmetrically so that any externally-generated noise impacts the (+) and (-) legs identically. When the (-) leg is inverted and summed with the (+) leg, that noise cancels itself out.