Balanced vs RCA between amp/preamp

My home system was dramatically improved by 2 instances of changing to XLR cables: the tube preamp (ARC) to SS amp (McIntosh) connection eliminated noise that was present with unbalanced cables (cables were about 7 feet long) & my Marantz SACD (SA-11S3) to the pre made a huge difference, whether only because the balanced connection was louder (as some attest) or the cable was of far better quality than the previous unbalanced one, I don't know.

Sorry, but posts like the above are just fanboy prattle, equivalent to
      "I changed everything and it sounded different."

Many balanced devices are bodged to accommodate unbalanced operation and coupled with generally incorrect balanced wiring, they don't stand a snowballs chance of optimum operation in unbalanced mode.

If 4+ decades in electronics has taught me anything, it's that if it can be screwed up it will be: 

• inexperienced engineers
• incompetent sales staff
• ignorant consumers
  

Regarding ground connection being connected first and disconnected last  IS true if one wire the balanced connections as perhaps intended. The shell which has the 4th terminal on a 3 prong XLR connector is intended for Chassis ground.  XLR connectors are available with up to 6 (7) termination points.  

Most however don't use this 4th connection point, including me.  Pin 1 Chassis Ground, Pin2 Positive Node Pin3 Negative node.  So to refer to the OP since your Marantz gear have the same termination on both pre and power amp - your in electrical phase and don't need to do anything else.

As far as balanced operation which in my opinion offer vastly improved performance dynamics for an example and noise rejection and that the interactions of the cable is practically eliminated the list goes on.  All the equipment we make is fully balanced form input to output. Even on our economy line Liberty Audio the gear is fully balanced.

Good Listening

Peter

https://pbnaudio.com

Thanks for your input, Peter (Pbnaudio). Yes, depending on the specific designs what could be connected first and disconnected last when XLR cables are connected and disconnected may be either chassis ground or circuit ground. As you are doing in your designs and as explained in this Rane application note, connection of pin 1 to chassis ground in both components is proper practice (although unfortunately far from universal practice), with connection of chassis to the shell being optional.

On another note, regarding whether or not the OP’s specific components are fully balanced and whether or not they use inexpensive op amps to generate or receive one or both signals in the balanced signal pairs, I see that service manuals for these components, presumably including schematics, can be downloaded at hifiengine.com if one is registered there. I’ll try to take a look at them tomorrow, as that site imposes a limit of three downloads per day and I’ve already reached that limit today.

Best regards,
-- Al