Millercarbon’s suggestion looks to me like an excellent one in this situation. The 30 watt specified power handling capability of the speaker-level to line-level converter he suggested seems reasonable in relation to the power capability of the OP’s amp (20 watts into 8 ohms; 40 watts into 4 ohms), considering that the amp is only likely to be run near max power when the music reaches very brief dynamic peaks. Also, problems can arise when driving a powered sub via the outputs of an amp that is balanced or bridged, depending on the internal grounding configuration of the sub and the amp and on whether one sub or two is being used. But in this case the OP’s amp is neither balanced or bridged, when it is used in stereo mode.
OP, glad you found the thread you linked to, which I remember well as I was instrumental in diagnosing the problem. As you may have seen in the thread, an XLR-to-RCA cable or adapter that is specially configured with XLR pin 3 unconnected can be a suitable solution in many such cases. But many designs which provide both XLR and RCA outputs provide the same signal to the non-inverted signal pin of the XLR connector that is provided to the RCA connector, in effect splitting that signal internally. Meaning that the results of using the XLR connector in conjunction with a suitably designed adapter, while using the RCA connector to drive the other component, would likely be little or no different than using the Audioquest splitters others have suggested. (I’ve used those splitters myself, btw, in a different application, with fine results given that the output impedance of the component providing the signal was low enough to properly drive the two input impedances and the capacitances of the two cables that were involved).
In any event, though, it appears that Miller’s suggestion is the preferable one in this case, for the reason Lalit stated. The only possible issue I can envision is the unlikely possibility of a ground loop-related hum.
Regards,
-- Al
OP, glad you found the thread you linked to, which I remember well as I was instrumental in diagnosing the problem. As you may have seen in the thread, an XLR-to-RCA cable or adapter that is specially configured with XLR pin 3 unconnected can be a suitable solution in many such cases. But many designs which provide both XLR and RCA outputs provide the same signal to the non-inverted signal pin of the XLR connector that is provided to the RCA connector, in effect splitting that signal internally. Meaning that the results of using the XLR connector in conjunction with a suitably designed adapter, while using the RCA connector to drive the other component, would likely be little or no different than using the Audioquest splitters others have suggested. (I’ve used those splitters myself, btw, in a different application, with fine results given that the output impedance of the component providing the signal was low enough to properly drive the two input impedances and the capacitances of the two cables that were involved).
In any event, though, it appears that Miller’s suggestion is the preferable one in this case, for the reason Lalit stated. The only possible issue I can envision is the unlikely possibility of a ground loop-related hum.
Regards,
-- Al