XLR out on a tuner?

Based on the Denon specs sheet, output voltage is the same regardless of the output selected.

Dan (Celander), where do you see that? What I see here is simply a reference to "output voltage 500mV / 2.2 kΩ." I would not infer from that that the balanced and unbalanced output voltages are the same; it is quite possible that the spec applies to one of the two outputs (probably the RCA output, given the 500 mv amplitude), with the voltage of the other output not being indicated. Also, while as you said balanced output voltages are commonly stated to be twice as great as unbalanced output voltages, with the balanced output voltages being implicitly defined as the instantaneous voltage difference between the two signals in a balanced signal pair, I’ve seen a number of instances over the years in which balanced output voltages (and also impedances) have been defined on the basis of each of the two signals in a balanced signal pair. As confirmed by John Atkinson’s measurements of some components that have been published in Stereophile.

Also, as I alluded to earlier, pro equipment is usually designed to accept and to supply balanced pairs of signals.

... if they used an op-amp on the XLR outputs to “split” the signal for balanced output, then each signal conductor would carry 1/2 the voltage.

No, that is not true. If an op amp is used to generate one of the two signals in a balanced signal pair by simply inverting the other signal, as is done in many designs, the "split" (and it is not really a split) would not result in anything more than a miniscule change in the amplitude of either signal.

Regards,

-- Al

The tuner in question is made by Denon’s Pro division, and is described as providing balanced outputs. Both of those facts make it likely that its XLR outputs provide a balanced pair of signals. Given its low price, it is also very probable that as Cleeds said it uses an op amp (operational amplifier) integrated circuit at its outputs to create at least one of the two signals in the balanced signal pair, by inverting the other signal.

However, even if the XLR outputs provide just a single unbalanced signal it would not do any harm to connect them to the preamp’s balanced inputs. RCA-to-XLR adapters do essentially the same thing. A risk of damage might arise in some cases when using an XLR-to-RCA adapter on an XLR **output,** because most such adapters short the signal on pin 3 to ground (pin 1). Also, some Audio Research fully balanced power amps, which provide only XLR inputs, will not work properly if they are provided with unbalanced inputs. In those cases, though, the consequence would be a large reduction in power capability, and an increase in distortion. The only means by which damage might occur in that situation is if the amp were overdriven relative to its reduced power capability, the resulting clipped output waveform perhaps causing damage to tweeters.

Whether or not an XLR connection would be preferable to an RCA connection in this particular case depends on the specific design of the tuner, and perhaps also on the design of the preamp and the interconnect cable. Given the likelihood that the tuner uses an inexpensive op amp to generate at least one of the signals that is provided to the XLR connectors, though, I would expect that the odds are against it sounding better, and it very conceivably could sound worse.

Regards,
-- Al