Preamp Tonekit 12AX7 (5)


Availability: In stock

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Tone Kit with 5 12AX7's

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New upgraded tone kit

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  • New upgraded tone kit
  • NOS Beijing Foil getter 12AX7 - available at this price only with kit purchase


This is a the "5 12AX7" version of the Doug's Tubes preamp tube cocktail kit and we've received great feedback on it. We have upgraded all preamp tone kits with the Mullard brand over the Tung-Sol. There has been a supply disruption for chinese tubes, the Shuguang factory closed a year ago with no ETA for going back online. Ruby branded chinese AC5's are unavailable except for what is left in the retail supply channel so we have sourced original 2014 Shuguang 12AX7B's which are identical to the Ruby AC5 and screen them ourselves. The tonekit allows hi-fi and guitarists alike to experiment and "tube-roll" preamp tubes in different slots of their amp. We are now using the factory direct Shuguang 12AX7B in place of the Ruby AC5HG(same tube). Try the NOS Beijing Chinese(foil getter) 12AX7 instead of the JJ for amazing tone. Currently we're recommending the following :

V1 - Mullard CV4004(V2 in the Express series amps)

V2 - JJ ECC83(V1 in the Express series amps)HG or

V3 - Shuguang 12AX7B

V4 - Shuguang 12AX7B (V5 in the Express series amps)

V5 - Mullard 12AX7(V4 in the Express series amps)

Customer Reviews

Mesa Express 5:50 Review by Caton
Hey Doug,

Just wanted to let you know I received and installed the 5 x 12AX7 kit into my Mesa, and I absolutely love it. I liked the amp enough before, but with this kit installed, it's become, for lack of a better term, hi-fi on clean channel. And now, I am actually super pleased with the blues channel, which I had never really liked before. This is my first tube swap of any kind, so it has me wondering if you would have a suggestion for a '68 Custom Princeton Reverb (reissue).

Thanks Again!
Caton S. (Posted on 5/18/20)
MESA 5:50 non-plus Pre-Amp Re-Tube Review by Brian
I bought this amp from the original owner back in February and I liked the tone immediately. Note I said "liked it" and not "loved it". The owner couldn't remember when he'd last changed tubes and while it was a negotiating point, I still had to shell out more money for a re-tube. As recommended by MESA I went with their branded power tubes and "SP" low noise pre-amp tubes. I was shortly to be disappointed by the increase in hiss / white noise and the lack of increase in tonal characteristics with the new tubes.

I put the amp on the market to sell it- with the tubes I'd ordered new, for it. The first day on sale I had 8 "watchers" and over 100 "views". That night the idea of selling it kept bothering me. I had read about your pre-Amp tube "cocktail" and how folks claim it improved tone while significantly reducing white noise. I thought, what the heck; if it doesn't work, I'll sell those tubes too when I sell the amp. An email to Doug's explaining the situation was met with the recommendation to "go with the 5 12AX7 "kit". Four days later (a weekend was involved- shipping was quick; USPS was not) the tubes arrived and this morning I installed them.

The difference in both tone and reduction of white noise is nothing short of phenomenal! It's like someone took the blanket off the amp AND injected it with tone! Deep, rich tone! No B.S., it's like it's not even the same amp.I am SO thankful I didn't keep the amp on the market. And you bet your butt I'm ordering another set of this tube cocktail to have on hand as spares!

BTW- I went with the recommended placement positions as indicated in the "notes" at the bottom of the "Details" section. If you want to do the same, please pay attention to the recommendations for the "Express" amps in parenthesis for each preamp tube spot- V1~V5.

Thanks Doug! Ya saved me some heartache and gave me an amp I'm now very happy with!

Brian Mentzer
Sellersville, Pa. (Posted on 5/15/19)
Mesa Express 5:25 tube kit Review by Tommy
I started with this tube kit and then made a few changes. I went with the NOS Beijing China 12AX7. In fact, I used 2 of these. Made a huge difference to the burn channel. The gloves came off and now this amp growls with the best of them. The clean channel just sounds pristine.

V1 -- NOS Beijing China 12AX7
V2 - Tung Sol 12AX7
V3 - NOS Beijing China 12AX7
V4 -- Sovtek 12AX7LPS
V5 - Ruby 7025SS HG

Power tubes - NOS Russian 6N14N-EB
(Posted on 6/25/18)
MESA 5:50 Plus: Blah to Killer Blues/Classic Rock/Fusion/Country Monster! Review by DannyB
After playing my brand new MESA 5:50 Plus about 20 minutes, I shut it off and called Doug. New, the underlying tone was a blah, Mesa metalish tone. Doug recommended this tone kit. The tone went to really sweet, bluesy tone. Glassy to smooth to crunchy to molten. All the channels became more responsive. See my 5:50 Plus review at Sweetwater. I mention Doug's Tubes in the review!

I have since bought 3 other various sets for my other tube amps.

I can't recommend Doug's Tubes enough!

Thank you Doug! (Posted on 10/25/17)
JVM 205H - re-tubed with Tone Kit with 5 12AX7's and EL34LCZ Late rate Review by Marcelo Ramos
Wow!!! What just happened to my amp? What a awesome defined BIG headroom distortion!!!
What happened to the noise on OD Orange and Red? Yeah, my amp is noiseless as never before, and with such awesome definition and sustain. The two channels and all 6 positions are sounding great and for the first time I'm able to use the OD RED with no microphonic or noise. Due to the LATE RATE on the power tubes I have to push a little bit on the BIAS, 40 each side. I used to have 35 each with the Average… but you know what, this sounding much, much better, thicker, defined and clearly with less compression.
Also I have replaced all my JJ's ECC83S to Tone Kit with 512AX7's. Not sure with the package changes depending on the availability of the tubes, so to be registered mine came with:

V1 - Tung-SOL 12AX7
V2 - Ruby 12AX7ACZ HG
V3 and V4 - Ruby 7025SS HG
V5 - Sovtek 12AX7LPS

Thank you Doug's Tubes! (Posted on 9/6/17)
Mesa Express 5:50 Cocktail Kit Review by Thom
Nailed it, everything I didn't like about this amp vanished with this tube configuration. The blues channel was sterile and the crunch was good, now the blues channel sounds like a blackface with a tube screamer, crunch came alive as well as the high gain. This went from a really good amp to an OMG what am I playing through amp. The only bad thing is that I didn't order the tubes from Doug as I had them all laying around., but his prices are spot on and his expertise is priceless. (Posted on 7/21/17)
Mesa 5:50+ Review by Dave
Doug, I ended up getting a few of the tubes from your 5x 12AX7 kit (I already had a few them laying around unused actually. You were right on the money…that combo for the Mesa 5:50+ was perfect.
(Posted on 6/7/17)
Mesa Express 5:50 retube Review by Niko

I just installed the tubes. The amp seems to have a higher output, the added gain has some background noise when I crank it up.


Finally, this amp has some gonads! You helped transform it from a Mesa Nothing to a Mesa Boogie! This amp was too well behaved, thanks for helping me corrupt it, LOL.

Take care,
Niko (Posted on 4/8/17)
Marshall JVM410 Review by Todd
Recently had my JVM 410 retuned to your recommendations. Absolutely incredible results! Unfortunately, do to it sounding so good, I don't think the neighborhood likes either one of us!! Great job and thanks for the help! (Posted on 1/21/17)
Mesa Boogie Express 5:25 with Sovtek EL84 Review by Jeff
Thank you! Tubes arrived yesterday and I installed them. Made my mesa boogie express 5:25 come alive! Probably better than new. Thanks doug! (Posted on 5/3/16)
Mesa Boogie Express 5:50 Review by Bill
Hi Doug,

The tubes are absolutely fantastic! Like others I read in the testimonials with Mesa Express 5:50 amps, I was ready to sell it. The hiss was unbearable and the tones across the channels were a mess. The new tubes cleaned all that up and I'm loving the amp again.

Thanks again and when I get ready to retube the Twin I'll send in another order.

-Bill (Posted on 4/30/16)
Mesa Boogie Express 5:25 Review by Justin
Just wanted to say how happy I was with my purchase. I went from email sent asking for a tube recommendation to having the perfect tubes at my door in four days. Fantastic customer service and the tubes you recommended are absolutely perfect. I'll be back for all my tube needs, thank you again.
(Posted on 4/2/16)
Marshall JVM210H retube Review by Nathan
I recently contacted Doug to find out what he recommended for Marshall JVM that I had picked up used. I ended up going with the Preamp Tonekit (5) and a matched quad of Ruby EL34BSTR. The turn-around time was really fast and the tubes arrived packed extremely well. The free shipping was really fast! I installed the new tubes and biased and played for a couple of hours and I am very happy. I will be retubing my DSL40C soon and going the same route as the JVM. Excellent service and great tube recommendations. I am really glad to have found Doug's Tubes. (Posted on 10/16/15)
Mesa Boogie Express 5:50 super power Review by Robert
My Mesa Express 5:50 was hissing more than a pit of vipers.
It was so loud I had to put a smartgate in the loop...but that took tone away.
then I purchased the preamp tube set from Doug.
unbelievable ! The amp is quiet as a mouse and the touch sensitivity is phenomenal....
The Mesa sounds amazing
great job Doug!!! (Posted on 9/29/15)
Mesa Boogie Express 5:50 Tube Kit Review by John H.
I was ready to sell my Mesa until I heard about on a message board. After changing to this tube kit it is now my favorite amp! The amp was muddy and now it has clarity and spectacular tone. I emailed doug for advice on power tubes based on my playing style and he recommended two Ruby 6L6GCMS. I received a quick reply to my question and fast shipping. Fantastic service, fantastic quality. Thanks Doug! (Posted on 9/16/15)
Mesa Boogie Single Rectifier Review by Greg
Hey Doug,
Thank you! I just installed the single rectifier tube kit this morning.
It gave me exactly what I've been needing from my amp!
I switched from the original 6L6 tubes to the EL34's. It gave me the metal
punch I've been looking for and the pre amp tubes took the brashness out of the amp.

Thanks again,
Greg Ort guitarist Autoerotica (Posted on 3/30/15)
Carvin Valvemaster retube Review by Brian
Hi Doug, Just a note to say that the Ruby EL34's and 12ax7 Tone Kit that you recommended sound great in my Carvin Valvemaster. I played through it at a recording session last week, and the Drive channel had an explosive, shimmery sound. I love it! (Posted on 3/24/15)
Excellent kit for tube rolling Review by Pablo
This is the second Tone Kit I ordered from Doug.
I wouldn't buy tubes anywhere else, Doug is always attentive and reachable and his advice is honest.
Other places will charge you more for NOS tubes or "premium" packages, Doug's advice is based on tone knowledge, he even recommended me tubes that were cheaper than was I was shooting for but that were more agreeable with the tone I was looking for.
This particular kit I have it installed in a Mesa Express 5:50 and a Mesa Lonestar. Since both this amps have no cathode follower preamp spots, you can roll the tubes and experiment. I find that the Tung Sol on V1 and the Sovtek as Phase Inverter do improve the overall tone of the amp. Thanks so much again Doug!

Pablo (Posted on 9/10/14)
Huge Tonal improvement to the Blues Burn Channel Review by JohnnyK
I own a Mesa 5:25 Express - I recently got it used but in truly excellent condition. I bought it because the clean / crunch channel was so incredibly clean and expressive; however, the blues / burn channel was frankly disappointing. It sounded dull to muddy - esp. if I used anything other than the bridge pick-up. BUT, now that re-tubed with this kit, the clean/crunch is nearly identical (to me) and the distortion tone on the blues/burn is a HUGE improvement. Now I can dial in a really bustin ballsy rock tone. All I need to do is back-down the guitar volume to push my rhythm tone without going too far, then push-up a bit to push the leads right where they should be. BTW this is all with just the guitar (ESP Eclipse) and the amp - only the cord in between. Of course I use effects boxes, but, I wanted to hear what the amp alone could deliver. I'm very happy with this purchase - got a half my amp back!

THANKS A TON for building this kit and offering it to the masses!!!! (Posted on 8/1/13)
Mesa Express 5:25 retube Review by Mike
Wow- you are the man. Can't believe what a difference your tube selection has made to my Boogie 5:25 Express. Better than new. Thanks again (Posted on 9/24/12)
Mesa Express 5:50 tube kit Review by Mark
winged =C= SED 6L6GC's and the 5 x 12AX7 tone kit.


Got the new tubes installed – WOW never sounded better – thanks a ton for your help!

Mark K. (Posted on 6/27/12)
Mesa Express 5:50 tube kit Review by donnyb
2 x Svetlana 6L6GC's for the power tubes and the 5 x 12AX7's tone kit.

I want to report that I am very satisfied with the sound, more responsive to what I am doing with the plectrum, and another benefit is the big reduction in hiss from the amp in the distortion channel in idle, which when you are mic'd up though a big PA, is annoying.

Also the prompt service and responses from Doug were excellent.

Thanks again. Don (Posted on 6/4/12)

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