TUBE Facts and Info by MartyStrat54

Discussion in 'The Workbench' started by MartyStrat54, May 6, 2011.

  1. Richard Martin

    Richard Martin Member

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    Thanks for your advice! Can you tell me, What the voltage for my JVM 410h for the bias should be, I found different levels, one said 70mV for my power tubes or 35 mA per-side. Some else said between 68- and 70 is fine.
    I didn't want to change out without knowing what to bias them at. Tomorrow I have to try swapping out preamp tubes to see if I have a bad one? Have no output sound from my 1960 lead cab. Only when I plug my guitar into the FX-loop. Hope it's just a tube. Everything looks in mint condition, it's build was 2016. I got it from music dealer, it was a floor model. They said it had harldly been used, but I only put may 20-30 hours on it, in my home when it started acting up. So I purchased all new EL34 tubes and 2 new jjecc 83 tubes. Liked your post. Take care Rich Martin
     
  2. Richard Martin

    Richard Martin Member

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    Hi, hope you don't mind, had another question for you! I like the southern rock sound, like dicky Betts, that almanbrothers sound blues. My JVM 410h is stock, still fairly new. What do you think of those mod changes. I herd they can make your Marshall sound much better? I have no idea. I am a old timer from the 70's. Just started playing again after many years, not being able. I'm not a follower of medle sound. I like high gain, but not to much, I love hearing every note, and love long sastain! Thank you again.
     
  3. SkidFx

    SkidFx New Member

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    Sweet track!!
     
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  4. HAMPAMP TUBE AMP SERVICES

    HAMPAMP TUBE AMP SERVICES Member

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    That is a real fine article Marty my friend but I have to say that my survival kit is an extra head or two and a spare cabinet, damn, need to consider a spare effects board too. All kidding aside, great information, I need to try some of these CP pre tubes, I buy them for customers but have never used a new production preamp tube for personal use since the early 80's. Power tubes are the exception to the rule here though.
     
  5. Grogshla

    Grogshla Active Member

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    Is it easy to roll your pre amp tubes? I am a complete novice when it comes to electronics. I would like to try a few different combinations and see which one I like the best.
    Any advice would be appreciated.
     
  6. nevermind

    nevermind Active Member

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    I didn't read all the posts, can a kind soul tell me if MS mentions any specific brand/model for this lopsided PI tubes reference?
     
  7. nevermind

    nevermind Active Member

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    Yes, too easy. Once you get the hang of pulling and inserting tubes correctly and without bending pins and cracking bakelite, you will find yourself swapping so much it will drive you towards the brink of insanity... YMMV of course!
     
  8. mickeydg5

    mickeydg5 Well-Known Member

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    He is reffering to the 12DW7/7247/ECC832 and ECC823(reversed) type tubes.

    They are a 12AX7 and 12AU7 in one bottle.
     
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  9. Joe6BG6GA

    Joe6BG6GA New Member

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    Greetings! Great advice! A good article Joe6BG6GA
     
  10. bordonbert

    bordonbert Member

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    Hmmm! Interesting reading on a controvesial topic. Have a look here: https://www.amplifiedparts.com/tech-articles/12ax7-comparison-current-made-tubes These guys prove the truth about different valve sounds. Of course, they sell them for a living and they also don't mind absolutely blatantly frigging the results into a series of pretty coloured but meaningless bar charts to confuse the unwary once they get them, but if you ignore the pretty pictures and coloured chaff and look at their very last graph on the page, the one of each tube frequency response laid onto a single plot, you will see the real difference. Their engineering is sound and you can read the truth from it, their interpretation of the results is disgraceful.
     
  11. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Interesting read. Not sure if I agree with their tube tone descriptions because I have a majority of these tubes and my ears and or amp all seem to react with a tone slightly different than they describe. It’s the same old deal, buy them and try them for yourself!
     
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  12. mickeydg5

    mickeydg5 Well-Known Member

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    At the end of the day what is wanted is a tube that compliments your amplifier and gear whether you need more low, mid or high frequency. The strongest ones are always the best (higher dB level).

    Our ears are vastly more sensitive to midrange. Notice the scoop in the midrange and how it works for humans.
     
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  13. bordonbert

    bordonbert Member

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    Sorry guys, in trying to be non-confrontational (if a little mildly sarcastic ;)) I made myself so subtle the point seems to have gone over everyone's head, maybe even including mine. Actually, what I meant was that if you look at that last graph and ignore the artificially created meaningless nonsense that is the individual descriptions and barcharts to sell the types you will see that, in fact, every one of those valves has exactly the same frequency response down to a small fraction of a dB. The point I was trying to suggest without stepping on the toes of the believers is that, if you get back to sound engineering, even though they were trying to prove there were differences, you can see that there is no real difference between valve type frequency responses at all. The only difference is a maximum of a couple of dB of gain which you can clearly see in the spread. Most of the types are within about 1dB of that too. All of that is usual in the component population from even just a single maker.

    EDIT: Oh, and the mid range scoop is there because the valves are being tested within a Fender preamp circuit. I don't think it suggests that the valve has a curve like that at all.
     
  14. mickeydg5

    mickeydg5 Well-Known Member

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    I was wondering if you would pick up on that and comment. :)
    Yes the curve(s) do look familiar, do they not?

    Still a stronger tube gives people more of what they want. Strength means something when it comes to bass, midrange clarity and chime.
     
  15. shredhell

    shredhell New Member

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    Great Info there, Thank You. Im going to be replacing the stock EH 12ax7 tubes in my mode four, looking at either russian made EH, or JJ ecc83 - or JJ ec803s high performance..Marty do you have any advice or recommendations?
     
  16. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    volume, in it's self gives a different perceived tonal balance...

    then we can discuss psychoacoustics, where people can hear stuff that's not there...

    But, perception by the end user is (almost) everything. If you don't perceive it, it doesn't exist (to you).
     
    Last edited: Sep 21, 2019
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  17. Lukas

    Lukas Well-Known Member

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    So I know this thread and conversation is years old but still being added to obviously. I have tubes in my JVM 210 that are pushing 6 years but still sound great to me. Marty talks about running old tubes being a risk to damaging your amp but when should I change them if they still sound great. I have other amps so this guy doesn’t get played all the time as it’s a full stack aswell and sometimes just to loud for home use. I’m running SVETLANA EL34’s biased to 37mv and V1&2 JJ ECC83’s, V3&4 JJ ECC803’s, V5 JJ ECC83. Hard to tell the hours on the tubes but I’d say at least 200-250hrs and when I do play it I typically push it hard. The stock tubes made it about 3 years before I changed them. Had one channel completely get super quiet so it was a tell tale sign something crapped out. Do Tubes slowly degrade that you don’t notice the difference over time in tone? Or are they just working properly or not? I’d rather not wait till one just gives up the ghost but hard to justify changing them if the amp still sounds killer.
     
    Last edited: Sep 30, 2019
  18. EndGame00

    EndGame00 Well-Known Member

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    Bought a pair of TAD el-34, and a couple of genalex 12ax7... Gonna try them on my Plexi clone...
     
  19. mickeydg5

    mickeydg5 Well-Known Member

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    Years old and time in use are two totally different things. 250 hours on tubes is not much at all especially if it aint maxed. I have tubes that are 25 years old that sound better than some new from the store tubes.
    The terms should be "hours used" or "worn" and not "years old" for tubes. When they are worn enough there will be signs like losses of clarity, top end, bottom end or off-sounding as not in its normal voice.
    Of course tubes can fail at any time but maybe more likely as they are more used/worn.
     
    Last edited: Dec 9, 2019
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  20. dna9656

    dna9656 Member

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    So Marty;
    I'm a long time player but pretty ignorant of tube swapping. I enjoyed your post as far as i could understand it but you use some jargon I'm not familiar with; like the term "roll tubes into..." Also how do i know that a certain tube in a particular socket won't damage my amp? I see there are a LOT of 12AX7s out there with letters at the end of themodel number I know I can look this information up but that still leaves me not knowing what the amp can handle....
     

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