Single ended phono into a truly balance preamp

[Kimo]

Perhaps, this is a silly question, but I have been unable to find a direct answer.

 

Will a single ended phono stage providing 60 db of gain running into fully balanced preamp via xlr adapters produce the same volume as a fully balanced phono providing 54 db of gain running into the same preamp?  If so, what would be the advantage of using a fully balanced output, other than noise rejection?  Thanks in advance.

[mansr]

A differential input cares only about the difference between the positive and negative signals (XLR pin 2 and 3). When using a single-ended source, the negative input (pin 3) is grounded and the signal connected to the positive input (pin 2). To get the same output level, the single ended input needs to have twice the amplitude of each half of the differential signal with respect to ground. If your 54 dB gain figure refers to this rather than the differential voltage, then yes, those phono stages should produce the same volume. That's assuming such a single-ended signal doesn't exceed the common-mode range of the input.

 

Regarding your second question, the advantage of balanced signals is indeed noise rejection, both picked up EMI and ground loop related.

[Kimo]

1 hour ago, mansr said:

A differential input cares only about the difference between the positive and negative signals (XLR pin 2 and 3). When using a single-ended source, the negative input (pin 3) is grounded and the signal connected to the positive input (pin 2). To get the same output level, the single ended input needs to have twice the amplitude of each half of the differential signal with respect to ground. If your 54 dB gain figure refers to this rather than the differential voltage, then yes, those phono stages should produce the same volume. That's assuming such a single-ended signal doesn't exceed the common-mode range of the input.

 

Regarding your second question, the advantage of balanced signals is indeed noise rejection, both picked up EMI and ground loop related.

Great.  Thanks.  Based on what you have stated, it sounds like I should use a balanced cable and convert at the single ended source, rather than the other way around.  Is this correct?

[mansr]

25 minutes ago, Kimo said:

Great.  Thanks.  Based on what you have stated, it sounds like I should use a balanced cable and convert at the single ended source, rather than the other way around.  Is this correct?

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