When I'm evaluating gear I like to spend some "quality time" listening to item A, then some "quality time" listening to item B.
From 1978 thru 1982 I worked in high end audio shops in the DC area. It was common to be able to A/B speakers, but at one of the shops we had this "computerized" console, where you could A/B amplifiers, and it was "programmed" to set the volumes equal. I remember a customer spending HOURS A/Bing a McIntosh MC2205 solid state power amp vs. a Luxman Laboratory Reference tube unit, switching back and forth causing the "computerized" console to illuminate one lamp for the McIntosh, the other for the Luxman. After HOURS of listening, he bought the Luxman. A few days after he left the store, our head repair tech came into our high end room and replaced the motherboard in the unit, saying that though the unit switched from one lamp to the other, it was not actually switching from one amp to another...so this customer was probably listening all the time to the McIntosh.
From 1978 thru 1982 I worked in high end audio shops in the DC area. It was common to be able to A/B speakers, but at one of the shops we had this "computerized" console, where you could A/B amplifiers, and it was "programmed" to set the volumes equal. I remember a customer spending HOURS A/Bing a McIntosh MC2205 solid state power amp vs. a Luxman Laboratory Reference tube unit, switching back and forth causing the "computerized" console to illuminate one lamp for the McIntosh, the other for the Luxman. After HOURS of listening, he bought the Luxman. A few days after he left the store, our head repair tech came into our high end room and replaced the motherboard in the unit, saying that though the unit switched from one lamp to the other, it was not actually switching from one amp to another...so this customer was probably listening all the time to the McIntosh.