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Tube / valve rolling - 12ax7 ! Thoughts


Here one that has been beat to Death many times ! I've been on tube shoping spree , I've bought New JJ's , Nos Baldwin/Sylvania , Tungsram ,Philips No super exspensive stuff. I test that they work on my Epi valve jr (1 12ax7 + 1 EL 84 ). This might not be the right amp sound testing , and my ears are not the best, but I think that the JJ's sound just as good as the others , maybe even quieter on idle than some of the Nos . I was suprised buy this. Been Reading to much ? Tubes that I have blown or made noise, have all been 10- 15 year old China stuff. My amps from the 60's, all have old pre amp tubes - I have not had to change them (if it Works ,don't mess With it) , so I know they last. I have not tried these new tubes in the big guns yet . How do you folks think these New Production tubes work these days (vs Nos priced at or a little above) ?


Most will disagree with me, but I spent several years selling vintage tubes on ebay and had some of the most coveted NOS 12AX7 come through my hands. Of course having read a lot about this on the internet I wanted to try them in the V1 spot of my amp. Telefunken, Amperex, tung-sol, RCA Blackplates, RCA greyplates, the coveted hippy RCA rainbow plate, you name it. I'm pretty picky about my sound and I found all these vintage tubes sounded GREAT! I also tried vintage Japanese tubes, less coveted brands ANNND current production 12AX7 varieties as they came to me. They all sounded GREAT too! In fact as long as the tube was in good working condition, still had a good amount of life left and wasn't microphonic I don't think I could tell them apart in a blind test.

The modern ones will work great in your vintage amps. That said some people have reported quality control issues with some early Chinese and Russian production, None of thsi is likely to kill your amp though especially in the preamp section.

My two bits.


The differences in 12AX7 types in V1 in a guitar amp are very subtle. At home in a quiet environment, sure, I can hear differences, but again, they are subtle. Some will react differently when pushed into saturation. In a live setting, I honestly don't think I could notice the differences unless it was a very quiet gig, like a jazz duo, etc. Also, one tube might sound bad in one amp and good in another.

Where I have noticed a difference between current production tubes and old (used or NOS) is in reliability and longevity. The old tubes were generally built to higher standards than most contemporary ones. Same goes for power tubes. Loved the new Tung Sol 6V6s in my DR but they can't handle the voltages; blew two of them within months. The Gold Lions sounded great too, but one blew after a couple of years. I did blow one old Tung Sol, but it was 50 years old and used when I got it. All my other 6v6 tubes are old and still going strong, same with the old 12AX types in my amps.


Tube rolling can be such a hit-or-miss exercise. I've had significant differences and near zero differences. However I did learn one thing that I've read wouldn't occur, I've heard differences in power tubes that were about as drastic as swapping pre tubes. Bottom line is you won't know until you try.


The differences I've heard in power tubes had a lot to do with biasing. Meaning I can put in one set and have the bias very hot whilst another will bias very cold if the amps bias is not adjusted accordingly(assuming it can be. This will make a BIG difference in the sound of your amp. I am not however discounting your experience at all.

Old production tubes were made when everything ran on tubes so they pretty well had it figured out. Modern tubes are , in the big picture, more of a specialty item.


The reason for asking is I have 2 larger amps that have a mix of no name China/ussr pre amp tubes. Some of these have been fizzing out with use lately. All my spares ,are the same no name stuff. So time to clean up /Stock up . Buying NOS on ebay feels a little like rolling the dice . It's gone fine so far. But Postage and maybe customs and having to retuning item for a refund - adds up. Buying new stuff dosen't have that problem. I hope the quality is on the rise !


I've had a bunch of NOS preamp tubes (Raytheon, RCA, JAN Philips, etc) in my amps, and I hear no difference from the brand-new, off-the-shelf JJs. Spend your money elsewhere.

JJs have to be some of the most reliable tubes I've used too.


The differences I hear are at near breakup volume in that the note sounds fatter and rounder to me,if that makes sense. At normal room volumes,not so much.


I've always said that you can get WAY more results in sound with a strategically placed 25 cent capacitor than you can get swapping out hundred dollar NOS tubes. Speakers make a difference to. Tube rolling is a waste of time. The older tubes might have been built a little better but the sound difference is minimal. It's like a bunch of car hot rodders obsessing over the tires and ignoring the engine, fuel, brakes, aerodynamics, weight etc....


The differences I hear are at near breakup volume in that the note sounds fatter and rounder to me,if that makes sense. At normal room volumes,not so much.

– Opie

The difference of a degree on the volume knob can do that too


I believe speakers are the biggest single component in your amp for a noticeable sound upgrade/change. That is if you're not planning on messing with the actual circuit itself.


Some tubes are just more musical and quieter than others. I have some Fisher branded Telefunkens that are just amazing. I’ve had NOS USA tubes that sound good but are really microphonic. Never been happy with any Chinese made 12AX7. The Russian tubes have improved a lot. Everyone has a favorite. I lean toward the new Tung Sol’s and avoid JJ’s, but most guys are just the opposite.


Ive pulled tubes out of old stero consols that work and sound great to me. Ran the same tubes fir 25 years in my old recird player, sounds good to me. Someday i might need to change one. Still running two 4-400's that i put in an rf amp i bought in 89. I agree with the cap statement. Design is more important than most tubes.


Well , I'm not really trying change the sound by changing tubes . Just that I need some new ones now, and decided to buy a some different ones and see if I notice the big difference between new and Nos in the same price range. So far I haven't , and from what I'm reeding here also , I might as well play it safe and try out different new production ones first . Besides - And this might all be in my head - what I have in there now, must be the lowest grade made ! Quality Nos do show up here too -might be expensive -not always - it's waiting game.


JJ's are the absolute worst tubes ever made anywhere by anybody.


JJ's are the absolute worst tubes ever made anywhere by anybody.

– Billy Zoom

Yep,couldnt agree more.


I've had more luck with EH 6V6s than JJs. I found the JJs went microphonic pretty quickly.

Frankly I have so many old tubes left over that I don't need to buy any new preamp tubes though I have tried them as they came to me. Generally I keep those and the less pricey of the vintage tubes. Japanese old production are very good and can still be found for reasonable prices.

If you want old tubes keep an eye out for old reel to reels, film projectors, console stereos, hifis, organs!!! etc etc. Many of these things are impractical to repair and are frankly heading to be wasted in a landfill. Salvaging and reusing the parts is better than tossing them. I've built most of my amps from salvaged main components, they work and sound great.


Tip. Ham radio clubs have flea markets for their surplus stuff. They call them hamfests. You can find them through their version of the nra. Its arrl. American radio relat leauge. Surplus computer stuff and misc radio equipment. Ive bought large boxes of various tubes for five bucks. Most are old tubes that are still in the box never used. Resistors and caps and old boards loaded with components.


Preamp tube rolling in my experience is anything but a waste of time. I've tried different 12ax7s/12ay7s/12at7s and equivalent in many amps, repeatedly, for years. Any number of NOS tubes, JJs, new Chinese, new Tung sols, EH. Dozens and dozens. Lessons learned:

  • JJ preamp tubes are typically flat and dead sounding. Never hard to do better than JJs.
  • The best choices - for V1 and V2 - usually end up for me to be something NOS. Not always. More often than not.
  • The differences for preamp tube choice - for V1 and V2 - can range from subtle to unmistakeable. Every amp seems to be different in which tubes are best, how different tubes sound.
  • Tube origin seems less predictable in tonal effect for the PI and reverb slots.
  • I've had several JJ 12at7s burn out in hours when used for reverb. Reverb seems to be hard on preamp tubes generally.

Hard to separate the impact of trying preamp vs. power tubes. I end up experimenting with both. NOS typically wins, but JJ 6v6s can sound excellent too. Same goes for Tung Sol 6v6s. The overall results from tube rolling that I've heard are not subtle. It's always worth trying. MD


i found that rolling 12AX7s definitely made a difference. i like GE and Amperex the most, and really liked a Fisher/Telefunken in V3 on my Laney VC30 because half of V3 runs the Drive channel, for which i wanted the cleanest possible tube. currently, though, i have modern Mullards because i just don't have the time to mess around with rolling. i don't think that power tubes are different enough to matter.


I'll echo some earlier comments. I have had good luck with JJ 6V6 tubes in my Deluxe Reverb--strangely better than with the NOS RCAs that I paid too much money for-- but, as someone mentioned earlier, the JJ12AT7 hasn't been a reliable reverb driver for me. For what it is worth.

I have never been afraid of swapping tubes. I put a pair of NOS Phillips 6L6 in my homemade Bassman and it was like having a different --and better--amp (the Phillips replaced a set of Fender/GT).


I still think your time is much better spent playing guitar than playing with tubes, and I build my own amps from scratch and have a lot of tubes. I spend NO time swapping them in and out and I have good ears. I will replace them if they go microphonic or get weak.


JJ's are the absolute worst tubes ever made anywhere by anybody.

– Billy Zoom

Any suggestions on current production tubes that are any good? I can't afford of find NOS tubes that are any good. I use JJ's because that's what I can get

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