Lots of good knowledge and experience here. Thanks. When I ordered mine I opted for a slight upgrade in the preamp, to NOS GEs. In the power pre-stage I took their advice to go better for some Brimar NOS tubes. They didn't put too much stock in the inverter stage. I explained I ready had some very nice NOS 12AU7 Mazda tubes I got through Brent Jesse from another piece. Out of the box it was lights out better than what i was coming from. 4 months later i was wondering how much better was possible so I asked Brent for a recommendation for the preamp row 1 12AT7 spots. I opted for some instrument grade RCA gray plates. The difference was audible in the staging. It was wide, discrete before but now it also seems deep. Eerie. Anyway I went back and rolled another, less pricey pair of 12Au7 in the inverter (JJ gold) but I couldn't hear much change. So yes, inverter row 3 seems less critical and 1 is for sure. With my extra sets and ability to swap rows one and two (both 12AT7), I have 24 possible combos. So I am trying to eliminate or focus on a few likely ones. Thanks for the tips all. Lots to digest for a new roller.
Which tube spots for which affects?
Here's something I've now been pondering about tube sets in preamps. Which positions in them are more likely to have what affect on the sound when rolling? For example my new-ish Raven Blackhawk has 3 pairs in the pre amp section that are noted as Preamp, Power amplifier first stage, Phase inverter/driver. Is one set more or less likely than the others to affect say, warmth or another pair dynamics? Which the sound stage? Are some locations better for a "euphonic" tube or a very accurate set? I'm sure it's really the sum of ALL the parts but maybe they each have their particular impacts. Hearing differences but wondering if there's a pattern/ causal/predictability to it all. I don't expect there's a single answer but maybe enough anecdotal evidence and experience might show a trend.