The GK-1 has two pre out connections (one for pre out (after the valve stage) to the power amp, another for pre out (before the valve stage), to the sub woofer amp). Does your selector look after this?
No, the switch only switches one input and the selector only selects one input as well. The official release of GK-1, which I got, does not have one more output before the valve.
If the subwoofer is connected before the power amp, it compensates the power amp spectrum while if it is connected after the power amp, it compensates the speaker spectrum. If the amps are to be comparied, the subwoofer is better to be used to compensate the speakers. At the same time, when a subwoofer is used to compensate speakers, the calibration is not a problem unlike it is used to compensate amps while different amps are comparied, in which case the calibration is to be done everytime the amp is changed.
I think when we do the AB tests, the subwoofer should be connected to compensate the speakers that are not under test.
In my home hifi, I always use subwoofer to compensate the speakers, which is the recommended configuration of my REL subwoofer. However, in a home theater, the subwoofer has to be connected to the LFE channel of the 5.1 decoder.
