Seeking a Warm 12AX7 Tube for Preamp

@trivema I think you might be on to something with the "too much gain" comment. I have noticed that I'm at 90dB spl with the volume control at only 9 o'clock. I found some used GE 5751 that I ordered from an eBay seller with a good reputation. He says they are tested, both sonically (matched) and electrically and are well within spec. Thanks for the tip @mulveling!

Just as a backup, I also bought some new Mullard Reissued 12AX7. So I'll have some things to try out and see if this beast can be tamed on the top end. 

I have to really thank everyone for all of the suggestions. I've read them all. And even if I haven't mentioned here, I have more options from your thoughts and thank everyone for taking the time. I'll have the tubes in this weekend and will post an update after I have some time to burn them in. 

G

@spacecadet65 (love the name btw), if you picked up the triple mica black plate GE 5751, you've got a real winner, I have one of those as well.  I also have a couple regular GE 5751 grey plate, they're pretty good too with a neutral, linear "softer" sound signature. 

If you're volume pot is 9 o'clock and 90 dB speaker output, something is running with high gain.  You could try attenuators on the amplifier inputs.  Initially I could not get the Willsenton volume past 9 o'clock, 10 max with 99dB sensitive Klipsch Fortes.  With 10dB attenuators I can now use more of the volume pot, the VU meters move more than a centimeter or two and no loss in sound quality, dynamics, rhythm pace or timing. Check out Parts Express, they have Harrison Labs in-line attenuators for RCA inputs.  You can also find XLR attenuators if you're running fully balanced interconnects. 

Another thing to consider is "tube synergy." What are the other tubes in the pre-amp circuit?  The next stage in the Willsenton is two 6SN7s each driving a 300B which drive 845 output tubes.  I've found mixing and matching the 12AX7/5751/12AT7 with certain 6SN7s can also make a sonic difference. 

My favorite 6SN7 in the Willsenton are Tung Sol WGTA brown base JAN.  Great combination of warmth, lots of detail and punch.  Sylvania WGTs, WGTAs and WGTBs are more mellow, less detail but have a lot of warmth.  RCAs are smoother, less detail, less warmth, but very neutral, linear frequency response and can stand a "hotter" 12AX7 to punch them up a notch.  Raytheon WGTAs and WGTBs are a touch grainy, think guitar amp in overdrive, and marry better with a softer V1 like the GE 5751 or a Telefunken 12AT7.   

I probably spend too much time swapping tubes in and out, but that is part of the fun of a good tube amp I guess. 

The picture of the GE 5751s that I'm waiting to come in look to be gray plates.  The other 2 tubes are 12AT7 and I have Mullard reissue in those. I don't know what other tubes are interchangeable with those. But I can already see how I might lose myself in a rabbit hole here. LOL

I'm scheduled to get the shipments in tomorrow. I'll let you know how it goes.

G

Oh it’s a rabbit hole for sure! I’ve ended up with four tube amps, one tube/SS hybrid and a collection of over 250 vacuum tubes. The tubes will outlive me AND my children! Unlike my wine cellar which always seems low, wonder why?

BTW, rolled in one of the GE 5751s last night in front of Raytheon GTB listening to Beth Hart’s new release.  Very relaxed, smooth and warm presentation with plenty of detail.  I think you’ll really like the GE vs the strident JJ.
 

Dropping from the higher gain 12ax7/100 down to a 5751/70 or a 12aT7/60, just having the lower gain should make a difference to help calm things down some.

While I currently use mid 1960s Mullard Blackburn 12Au7 and 12At7s myself in my amps, the most important thing discovered is sourcing tubes from a great tube reseller with the best testing and validation equipment. Truly matters.  

For re-issue tubes, I’ve tried and still own many [if not all] of the new production tubes mentioned here above, they are nice backup test tubes for reference checks once in a while. While not as musical, some of the new PSVane small tubes and Genelex Gold Lyons have worked okay for me in multiple amplifiers. Try that 5751 for a while and maybe a good 12aT7 next in those spots, and you might be good enough, and just listen to the music.