I recommend calling VAC to find out about the differences between the RenIII and SigIIa phono stages. I might be wrong, but I think the line stages themselves are pretty different, with the SigIIa being lower gain. Another question for VAC.
And as I said above, I find the phono in my Phi Beta, which is the SigIIa circuit, to easily compete with my Manley Steelhead II. Don't know about the Pass. I did audition the Allnic at home a few years ago, although my system was quite different then, and I passed on it. I found it extremely liquid but ultimately somewhat colored and it hummed like mad. I preferred the Steelhead anyway. YMMV.
And as I said above, I find the phono in my Phi Beta, which is the SigIIa circuit, to easily compete with my Manley Steelhead II. Don't know about the Pass. I did audition the Allnic at home a few years ago, although my system was quite different then, and I passed on it. I found it extremely liquid but ultimately somewhat colored and it hummed like mad. I preferred the Steelhead anyway. YMMV.