At the May GM of the Club we did a blind A/B comparison between my 12AX7 Tube Preamp and OP Amp Preamp while the rest of the gear remained unchanged. No member knew whether he was listing to the valve or chip preamp, just A or B. Two similar tracks was played from a wide range of music styles the first track on one preamp and the second track on the other. The members voted 60/40 in favor of the chip preamp.