My preamp is a dealer demo so it had a lot of time on it. The phono stage, however, had a cap replaced and the screw terminals for impedance loading installed, so those changes require some break-in, as do the nude Vishays I use for loading. In my hands, the unit's been on for three weeks with probably 130 hours of playing time (I work at home and listen while I work). So, you're right, the phono section is probably not quite fully burned in, but close.
I probably should have mentioned that the Psvane tubes are not fully burned in yet. Psvane recommends around 100 hours and I have probably half that on them, so their character might change. But the sound has stayed pretty consistent so I doubt they'll change much. Brent was pretty emphatic that the VAC 12AX7s are his favorites in the Sig phono circuit. He has quite a collection of NOS 12AX7s but prefers the stock ones in there. I have to agree.
I'm coming to the conclusion, subject to revision, that the Manley phono stage is a bit better. The VAC is excellent, don't get me wrong. I completely enjoy it and could easily be happy with it alone (if I only needed two MC inputs). But the Steelhead, right now, anyway, is more dynamic and throws a deeper, more articulate sound stage. My cartridges are all pretty low output, ranging from .2 to .28 mV. The VAC MC sections provide 60 db of gain, which is certainly enough for all of them to sound great. But the Steelhead may be selected for more gain yet, hence the increased dynamics. Running through the VAC linestage, the Manley sounds superb, better than I've ever heard it.
Since I'm running three arms (soon to be four) on two tables, it's good to be able to choose different phono sections for different arm/cartridge combos. But if I had to choose, at this point, anyway, I'd take the Manley. I haven't talked to VAC about the new stand-alone phono stage.
