SarnoMusicSolutions wrote:I love the sound of RCA 7025's or 12AX7's. There's something real nice about the top-top end, not so glassy, works well with a treble-on-10 kind of approach. ...
Just finished experimenting with V1 in my SMS. Did it together with my tech, Pete Cage (two sets of ears are better than one sometimes). http://www.audiocage.com/
Before we even opened up the SMS, Pete said, "This is a TR circuit, right? Then I'd say there's nothing better in a TR preamp than RCAs. Did you bring any with you?"
Turns out I did, but after some experimentation, a Raytheon 5751 won the day. Easy to make up the gain difference at the SMS's front gain knob. The tube is like the voice of angels in my SMS. I could not be more pleased now with its tone! It's still got all of the stock tube's treble (if not more) but with no icepick and the mids are so much more pleasing and present (indeed, I was running the preamp previously with the mid control dimed; with the Raytheon, I've backed it down to half).
I'd advise everyone with an SMS to at least try some alternate preamp tubes in your preamp's V1 (even if "I'm perfectly happy with the sound as is"). Takes little time, it's easy to remove the SMS cover to access the tube sockets (just remember to also unscrew the front panel screw), and is an interesting experience regardless of how you ultimately come out.
Just my 2 cents.