What do you know and how do you like the RCA 5963 Black Plates?

mulveling, did you compare various RCA blackplates from 50s to Raytheon blackplates from the same time period ? I really like the RCAs in the driver section and how they work together with 12AX7 Mullards in the preamp. I was thinking about trying both Raytheon blackplates and Mullard 12AU7 at some point, though there is no need really. 

mulveling, I see. I thought you had all VAC electronics, or this is your second system.

So, RCA 12AX7 black plates from 50s are not microphonic, I understand, I might want to try them too instead of Mullards, though I would not anticipate the improvement, but who knows ?

mulveling, I understand why some might not be particularly fond of Mullards, it is really a matter of taste and system match. I prefer somewhat loose vintage sound with silky highs and full bodied midrange. But perhaps even for me the full Mullard set-up would be too much of that. I will probably just stay with RCA blackplates for 12AU7 in the amp and Mullard lonplates for 12AX7 in the preamp.