Mesa/Boogie 12AX7 Preamp Tube Reviews

Based on the descriptions, I went with these for replacement tubes in my Laney VH100R. Very happy with both the high gain and edge of break-up tones - especially as compared to 20 year old stock tubes :) Would happily use these again in the future.

Improved the clean and dirty channels in my amp. Paired with Genalex KT77's.

I'm pretty happy. Sweetwater packed the tube very well with lots of padding and a couple of Fragile, please handle with care labels on the box. I took my sweet time and swapped out the stock JJ for the Mesa Boogie 12ax7 preamp tube in about 10 minutes. I have heard different things about touching the tube. I don't touch it with my bare hand, but opt for a thin plastic glove. The reason for this is that I don't want to risk getting oils on the tube because anything collecting on a tube will cause it to eventually overheat and shorten it's life. Bottom line, oil attracts dust. Enough about that. The stock JJ in the Micro-Dark is a quality tube and people love it. Orange didn't cut corners too many corners on the Micro-dark.

I was curious what Mesa Boogie could throw down as they are all about tube amps and I figured for $ that it was worth giving the swap out a go. The changes in tone are subtle. Both the Mesa and the JJ tubes are Hi-Gain. The Mesa Boogie tube seems to tease out a little more clarity of shape (Orange speak for tone) adjustments, this is very noticeable on my HSS American Pro 2 Strat and when played in combination with the Seymour Duncan Humbuckers in my Tele, all heck breaks loose. I'm getting crazy controllable feedback, squeals, break ups, you name it. It's there and usable. I didn't get that control with the JJ as it was definately more on the muddier side. I'm not a coil splitting fan, but both of my Fenders have coil splitting (it's a thing anymore I guess). I was pleasently surprised that the Mesa Tubes made the split coils much more livable. then the JJ did. That was a very obvious bonus. I'm not here to knock the JJ, as I'd put it in any preamp circuit. It's just that the Mesa is putting me more on the edge of the tone that I'm always chasing.

Used this tube to replace the 12AX7 in my Bugera G5 Infinium. It does not make a huge difference but it gets me a little bit close to the tone I'm looking for. Glad I purchased this tube.

I really like my Fender amp and opted to upgrade the tubes last weekend based on the reviews of the Mesa boogie line. YouTubers were indicating that a tube upgrade would make a difference for an amp.

The upgrade was super easy and the tone's improvement very noticeable.

The Fender Blue Junior IV is a really great amp for players who live and play guitar in a house and just want to chill in the den with clean tones. Replacing the factory stock tubes with these was a great investment. An already super nice product made better.

Thanks to Colton Smiricky, my Sweetwater rep, for doing a great job!

I swapped out the factory marshall tubes with these and right away I noticed a huge difference! The harmonics just scream and the amount of sustain,even on the clean channel is mind blowing.I know these are a bit pricey but Mesa sure got it right with these things.I had to dial the gain setting back a bit because of the amount of grit they put out.No hissing even at loud volumes so I would highly recommend these if you're looking to upgrade your tubes!

Okay i got this tube Friday and last night put in my blackstar HT stage 100 mk2.I was using TAD 7025 in the V1 well the tone was good I love it but the bass didn't care as much. Now with Mesa 12ax7 the tone is so sweet and open to that vintage tone and the bass is right on and clear!

Put 2 of these MB 12AX7's in a Fuchs ODS 100 to replace the JJ's in the pre amp. Gives a nice crisp breakup that I prefer over the JJ's. The JJ's broke up too soon and gave a softer (squishier) overdrive while the MB's hold the tone better and give a crisper overdrive when pushed. The Fuchs has a great sustain setting that also works better IMO with the MB's. Very pleased.

These tubes will add a transparent rich tone to your signal.

These tubes turned by Ampeg GVT15 from a so so amp to fantastic! Believe the hype and put these in all your amps!

After trying out several different power amp tubes and not hearing one bit of difference, I was skeptical to do the same with preamp tubes. I was totally wrong. Swap out your preamp tubes (or at least the first one) and get these for sure. You can definitely hear the difference.

Thanks, Sweetwater for pointing me in the right direction!

Installed 2 of these in a Blackheart Handsome Devil 15 combo amp. These tubes restored the gain and the clean tone significantly. These tubes sound great and are responsive to playing dynamics. Do your amp a favor and throw a set of these tubes in and light 'em up!

I replaced a groove tube 12 ax7 premium tube in the first tube next to the EL84 power tube in my bassbreaker 15. Iam so impressed with the mesa tube, I get effortless harmonics now also the gain is much higher. For instance the gain on 4 is like if I had the gain on 6 on the gt tube. I did notice that the bass is a bit lower in the mesa but all you gotta do is raise the level up a bit if you need. Highly recommend.

I did a complete tube swap replacing stock JJ tubes with Mesa 12AX7, 12AT7, and EL-84. The tone coming out of my Dark Terror now is simply amazing! Definitley worth the investment!

Purchased 3 of these tubes for my Aguilar DB751 bass amp. Compared to the Electro-harmonix 12AX7EH tubes that came in the head from the factory, the Mesa tubes give you better mid's and high's. Low end is very solid, and I could not detect any change in tone. The Mesa tubes are high gain, even more than the stock tubes. Overall, I feel the Mesa tubes are an upgrade, and I would not hesitate to buy them again.

I bought this for my crate 80dsp, it's tubes in the preamp and solid state power section. It takes two 12au7's and one 12ax7, so it is a pretty clean amp. I'm after that tube breakup sound at lower gain and volumes and this thing delivers. With the amps gain on 3 it's ever so slightly starting to drive, turn it to 6 and it's beautiful sweet overdriven sounds, dime it and you have wonderful distortion... ALL IN THE CLEAN CHANNEL. it gets rid of a decent amount of headroom, but I have a fender if I want squeaky clean. Buy these tubes for high quality tone and breakup

I got these to replace the ones in my Marshall JCM 2000 tsl. What a difference this thing sounds amazing!!!!! If you are looking to get metal tones like Pantera metallica Megadeth or slayer this is your preamp tube!!!!! I cannot say enough good things about this tube. It's has a very tight sound. I'm in A touring metal band and everybody has commented on the sound of my amp since I put these in. If you like metal, you will love this tube!!!!!!!!!!!!!

I like the direct swap, I tried some JJ EC803 one time, wasn't digging it, so went with these, great sound for my 5:50

I got one of these to replace the preamp tube in my Marshall Valvestate VS65R. It really made a world of difference. My clean channel sounds fuller and my overdrive has a noticeable increase in gain. I'm very impressed and will not think twice to buy these again.

I use this tube in my peavey xxx 60 watt combo. After $500 in tubes and testing. I use the JJ ecc83s in V1.mesa ecc83 in V2 and V3.and JJ ecc83s matched and balanced in phase invertor v4.And she provides warm distortion.I can dial in a nice rock n roll.and heavy overdrive. and the clean channel is superior. used with Ibanez tube screamer. That's my perfect match. power tubes jj kt 77. and I will switch sometimes using mesa 6l6gc power tubes.

The Zombie is supposed to be a Mesa/Boogie sounding amp. Well, this tube helps get it a little closer. I can't say there was a huge tonal difference, but there IS a enough to say it helped with the MB tone.

I changed the preamp tubes in my H&K Deluxe 20 as the dirty channel sounded a little harsh. These preamp tubes did a great job in adding some warmth to the both channels and removed some of the harshness, in particular on the dirty channel. The harmonics and tone are really nice. Well worth the money!!

I purchased these tubes for my H & K 18 12" Tubemeister Combo. This was done to improve the sound quality of the amp. The sound improvement is very very noticeable. The original tubes were very harsh sounding at higher volumes and when using the 2nd channel and or lead channel. It was so harsh on the 2nd channel that I only used channel 1. I can't say that the tubes were entirely responsible for eliminating the harshness because I also changed the speaker to a Celestion Neo Creamback. The 2 changes have improved the sound/tone of this amp considerably, especially on channel 2 and the lead channel which are now both very useful.

Used these tubes in my art map 2 mic pre and they really took some of the edge off my vocal and smoothed things out a bit and as always sweetwater delivered fast and everything was in working order

I replaced the pre amp tubes in my carvin Belair, very nice,...warmed it up and improved over all tone...I'm gonna try them out in my v3....I didn't give it a 5 because I haven't tried anything else...thanks, Sweetwater

I replaced the preamp tubes in my 72' with these, had heard alot of good things bout mesa so thought I would give it a shot! turned out awsome. Expected to lose some clean head room, It wasnt drastic though, very good tubes. It has an amazing tone. Cannot say that enough!! It responds great every note is awsome. Im a heavy blues influenced guitarist and these can produce an amazing sound for some modern day blues or even some SRV stuff if u turn that volume knob up!

I replaced the sovtec12Ax7 in my Hartke 60GT with this one. Immediate upgrade. It's a hybrid amp so I wasn't sure how much or if there'd be much difference. My dist isn't so fizzy now. More articulated sound. A pinch less dust but much rounder and smooth. Clean also warmer.

I bought 3 of these to change out stock tubes I"m my Hughes and kettner GM40. Out of the 3, 1 worked... 1 blew in my amp within 30mins in slot v1, the 2nd one only works in slot V2 or V3 and the last one was faulty, it never had a chance to live. Just wish I didn"t spend close to 80$ on 1 tube. I won"t be reordering any of these for a while. First time buying these tubes and it was a bad first time experience.

So, I got this one for either v1 or v3 in a Peavey 20 MH. It underperformed boFth a ender GT 12ax7 and a Tung-Sol 12ax7, in either position. It is noisier (by about 4 db, measured with gain and master maxed out and the guitar muted from the volume pot). But also, the sound was flatter, and less nuanced. So, I will, sadly, keep it as a spare. But I don't think I'll ever use it, since any standard 12ax7 will do better. I had been lucky actually with their more expensive offering of 12ax7, the mesa SPAX7. That one is indeed a really good, silent, high gain tube. At least the one I bought.