Balanced Phono question - forgive my ignorance

Dgarretson's response is correct except for what looks like a typo:

However, some phono stages not balanced all the way through have true-balanced output sections. In this case you will benefit going XLR from phono to pre.

I think the word 'not' goes between 'will' and 'benefit'.

I don't think there are too many phono sections out there that have XLR inputs but are not balanced, so its probably a moot point. We found that most people really didn't understand what we were up to with the balanced input on our phono section; I can't imagine why a manufacturer would take that on and *not* have at the same time a fully balanced (and in our case, differential) phono section inside.

I am using the Ayre P-5x phono pre which has balanced and single ended inputs. I use the balanced inputs with a custom made Audioquest Cheeta cables that have RCA connectors on the side that plugs into the VPI Aries (VPI did not have a xlr connection block option at the that time, they do now) and xlr on the other side for the P-5x. This option was described in the P-5x manual as the second best option for connectivity and works well for me.

If you think about it the phono pre end of the cable is like any xlr while the other end the cable the two balanced wires are connected to the rca center hot and the shield. AQ cable are a "balanced" design so it is a slight disadvantage to have the RCAs on the one end.

If I was starting now I would get the VPI xlr connection block, but at this point the things are electrically correct and it works.

TD

Thanks - I think I get it now. Cheers

TD,

I doubt you're giving up anything with your special cable. My guess is that if you take a multimeter you'll find that XLR pin 2 is connected to RCA hot, pin 3 is connected to RCA jacket, and pin 1 is connected to an RFI foil drain that floats unconnected at the RCA connector. This arrangement is no more or less balanced than using XLRs end-to-end.

Ralph,

My prior phono stage was an early BAT P10, which was balanced except for the first gain stage. At the time of this early production run, BAT favored SE input from tonearm & balanced output to pre. Subsequent P10s are balanced end-to-end. I assume there are other similar hybrid phono circuits still out there.

Dave

Hi Dave, the early BAT must be one of the few! Most of the phono sections I've seen with a balanced output are also balanced in.

TD, There is a way to run balanced operation from RCA jacks from a tone arm, provided the tone arm ground is on a seperate post. In such a case, the idea is to have the arm ground be the shield of both channels, and the barrel connection of the RCA is then the inverting output of the cartridge, going to pin 3 of the XLR. It should on no account be connected to ground. This setup will work fine with no hum problems.