I like to experiment with tubes in my 1965 (original, not re-issue) Princeton Reverb. I've recently been trying a 7025 and 12AY7 in the V1 position, to experiment with getting a greater range on the volume control at lower volumes using the latter. Both tubes I've tried are prime examples of NOS RCA tubes. According to what little I've found online, the 12AY7 is a "warmer" sounding tube...but in my case I've found exactly the opposite...the 7025 has noticeably more bass, to the point where the amp even sounds bass-shy with the 12AY7. It's no surprise to me that the 7025 sounds "bigger" and bolder, but I am surprised at the bass attenuation with the RCA 12AY7. The 7025 also drives the reverb better, but is noisier when you turn the reverb up. I'm curious to hear what other peoples' experiences are. Also, what about trying a lower-gain tube in V1 other than a 12AY7? My whole reason for doing these experiments is to get more usable range out of the volume control at lower volumes.