We have a good number of customers with Pass Labs amps, so I can say with confidence that if you go that route it will work fine. The MP-3 has no worries at all driving input impedances much lower.
I think the big differences you are likely to hear between these preamps will be at the frequency extremes. Essentially, three different coupling means are being used- one preamp uses output transformers, the next uses output coupling caps, and the 3rd (MP-3) has a direct-coupled output.
I think the big differences you are likely to hear between these preamps will be at the frequency extremes. Essentially, three different coupling means are being used- one preamp uses output transformers, the next uses output coupling caps, and the 3rd (MP-3) has a direct-coupled output.