Help: Accuphase XLR pin 3 hot into XLR pin 2 hot? (no unbalanced avail)


I'm picking up an old Accuphase G-18 equalizer to offset my hearing loss. My research shows that the G-18 has pin 3 hot.

How do I resolve this hook up anomaly, as the Accuphase has pin 3 hot, and my Boulder 865 has pin 2 hot? There are no unbalanced inputs on my Boulder.

Thanks, a befuddled Ken
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Showing 2 responses by almarg

You’re welcome, Ken.

Note, though, the second from the last paragraph in my post above. If you are providing the G-18 with balanced inputs, as well as using its balanced outputs, introducing that device into the signal path would **cause** a polarity reversal, that would not occur without it.

If the balanced inputs and balanced outputs of a component both have the same polarity, whether pin 2 or pin 3 of its connectors is referred to as "hot" is irrelevant.

It may be a different situation in the case of some professional microphones, which appears to be the intended application of that device, because the XLR connectors of most pro mics convey DC power into them in addition to conveying their output signals.

Regards,
-- Al



The term "hot" is somewhat misleading in the context of balanced interfaces. All it really means is that the signal polarity is "non-inverted," with the other signal in the balanced signal pair being "inverted."

And if those polarities are defined inconsistently between two components having a balanced interconnection the only consequence will be an inversion of "absolute phase," aka "polarity." The audible significance of which is controversial, as well as being inconsistent among different recordings.

Also, if you are using balanced inputs to the G-18 as well as balanced outputs, and assuming its inputs and outputs are both defined as pin 3 hot, the polarity of its output signals will be the same as the polarity of its input signals, and the fact that the amp and the G-18 specify different pins as being hot will be irrelevant.

But if you are providing the G-18 with unbalanced inputs, and if neither the Boulder nor the source component(s) are polarity inverting, you can restore the correct overall polarity by simply interchanging + and - on either the amplifier outputs or the speaker inputs. Although as I say it may very well not matter either way, to many or most listeners on most or all recordings.

Regards,
-- Al