While the ARS Chinese 12ax7's in slot V1 were definitely an upgrade for me in terms of overall tone (JJ's have a huge 250-400 Hz presence that doesn't work for my ears), I wasn't 100% happy with the tones. This past weekend, I decided to try an NOS GE 5751 I had lying around in the V1 slot of the Soldano SLO, which have 30% less gain than the standard 12ax7.
Mind blown! I wish I had tried this two years ago!
Now, the low mid bump is completely gone! The SLO sound really tight, yet it has more bass than before. I called ARS and ordered six more GE 5751's and replaced the V1 tube in every module and seriously, they're a game changer for me. All of the modules have so much more clarity. It's like someone took a blanket off the speaker! The modules aren't "brighter" or more treble-y but they're so much clearer sounding. And there's no difference in gain structure. I thought that I might be giving up some distortion in favor of more headroom but they all have just as much gain as with the JJ's or ARS Chinese 12ax7's, which was a little surprising but also very welcome.
The 5751 really cleaned up and tightened the bottom end on the Plexi and especially the Metropolis, both of which provide monster tones now. Gone is the mushy bottom end on the MetroPlex while the Friedman Plexi has so much more range than before in terms of dialing in cleaner and dirtier tones. They're all just absolutely freaking killer!
I realize that the GE NOS 5751's are definitely on the pricier side but these are the best guitar tones I've ever recorded - bar none - and have made a huge difference. I'll post some tracks in the coming weeks.