JJ Electronics T-12AT7-JJ Amplifier Tube

This tune reduced my overly loud amp great! Line 6 spider valve big bee amp 40watt, it has a volume issue gets loud fast, put this tube in valve 1 and now this is a useable amp for home use. Made my amp very useable . Very please

This is a great tube.

I generally don't have a very high opinion of JJ. They get props for being really early in the game, they've been in the tube repro world for over 10 years now. But they haven't changed or improved in all that time. You just have to know what ones are good and what ones to miss. For instance, the ECC803, the long plate 12AX7 that they produce, has a decent tone, but heavy on the bottom end and weak on the top, which works great for some applications like bass amps, except for the extremely high, hissy noise floor. Their regular 12AX7 is totally fine, acceptable, but not exceptional like the Mullard repro or the Electro-Harmonix 12AX7EH (which is the best 12AX7 currently on the market). The rectifier tubes that JJ makes are all great. They don't cause weird voltage spikes and fulfill exactly the role they are supposed to do. This one just knocks it out of the park though. It's definitely at the higher end of the gain spectrum for the 12AT7 genre, but that's what you want. And the noise floor is, well, there's no floor at all. It's just noiseless. In a reverb driver position (undoubtedly what most people are buying 12AT7s for), this is what you want, because it can so readily pick up ambient hiss from the springs. This one just excels at hearing your reverb noise but not the ambient noise. I don't understand why Electro-Harmonix makes one of the best 12AX7s but one of the worst 12AT7s, but in my JJ is the only one to buy. You can also use this in your PI slot to lower your breakup point on your power tubes. So yeah, if you're a JJ skeptic like I am, trust me when I say, this is one of the good ones.

This is a great sounding tube that did just the trick when it comes to taming the beast that is my fender hot rod deluxe. This tube is 60% the gain of a 12ax7 preamp tube and makes the clean channels volume manageable. Nice warm tone too. No complaints and on my amp, mandatory.

If you have a Fender Hot Rod Deluxe / DeVille amp and are looking to tame the beast, rather get a more acceptable practice amp for home use, try replacing the V1 preamp tube with one 12AT7. I tried this JJ / Tesla 12AT7 in place of the first 12AX7 preamp tube to lower the gain slightly at the first amp stage. It makes a considerable difference and keeps the clean and master volume from being too touch sensitive and being WAY too loud when slightly above 1 on the gain level. It's a cheap alternative to a hot-plate attenuator and doesn't require re-wiring the internal guts of your amp. Simply swap out the first 12AX7 tube for a 12AT7. This JJ / Tesla tube (as well as their entire kit) is extremely clean sounding with no microphonics or tube rattle. Works well for me on my 1999 / 2000 early Made in USA Fender Hot Rod Deluxe amp. Love it.

Arrived promptly. Exactly what I needed for my cathode follower

My go-to tube if I need a quick, inexpensive replacement. They sound great and you can't beat the quality for the price. They work well in virtually any slot in a guitar amp. There are better tubes out there, but if you aren't very particular about your tubes or don't want to spend a lot of money on high end tubes then this is a great option to fill any need. I also use them in a mic preamp and they really improved the warmth over the cheap, stock tubes that originally were in it.

I like these 12ax7s the best out of the newer tubes for high gain and actually i bought this 12at7 to take a little gain out of my PRS mt15 to make it a little more usable for more hard rock sounds. That amp is all screamer and i love love love the clean sound but actually wanted to try a little less gain to get more usable crunch sounds while still having plenty of gain.