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My Vox Ac30 and my V1 V2 V3

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  • My Vox Ac30 and my V1 V2 V3

    Bought a used Vox AC30CC2X recently and decided to replace the tubes as I think they're stock and the amp has like 3 years on playing on it


    I'm in a band that plays regularly Northeast Boston and Brooklyn, so I want to make sure the pressence is there, you know?


    So for the power tubes I'm going to put in JJs EL84s and also putting in a GZ34


    so for the preamp tubes, I got advice for V1 to put like a JJ longplate ECC803S


    I also read an article talking about the V3 PI and that they suggest a Sovtek 12AX7LPS


    But I also keep hearing people saying to have a Tung-Sol over JJs


    so I'm starting to think these 3 options before I move into putting things into reality and thought I'd ask for some input


    Option 1 V1 JJ longplate ECC803S  V2 and V3 JJ ECC83s 


    Option 2 V1 JJ longplate ECC803S V2 JJ ECC83s  V3 for PI consideration Sovtek 12AX7LPS


    Option 3 Maybe get crazy V1 JJ longplate ECC803S V2 Tung-Sol 12AX7  V3 Sovtek 12AX7LPS


    Kinda leaning towards option 2...Am I overthinking this and just should do something like option 1?



  • #2
    my first answer, if it ain't broken, don't try to fix it

    if your amp works and sounds great why do you want to change the tubes?

    i use the cheapest tubes available and don't care about NOS
    so for preamp i use usually sovteks, depending on which amp and how much gain i want/need i select the "right" for V1

    putting a 12AX7LPS with less gain output in V3 seems counter productive...
    the biigest single change you get at V1 by controlling the input gain, decide if you want more or less...

    but define your goal and then select your tubes, just putting some NOS stuff randomly in your amp will not help


    • albano1973
      albano1973 commented
      Editing a comment

      yeah I might be over thinking it 

  • #3

    The differences between tubes is very little. Its going to be hard for you to notice a change, difficult for your band mates to hear any difference and the chances of your audience hearing a difference? They wont have a clue.

    I usually stick with matching tubes all around. I've done all that kind of swapping around over the years and for some amp builds it makes a very small difference. If you want different tone you'd be better off trying different speakers. That's where you get the biggest bang for the buck. You can get higher SPL speakers and make the amp much louder, thinner speakers so you have more string touch come through, lower SPL to reduce the volume so it sounds better miced, and you have a wide variety of frequency responses for tonal shaping.

     If all you need is a small change go for it. Just don't expect a big difference. Changing string brands can easily produce double or triple the difference in tonal changes than a tube substitute can have in most guitar amps.

    The reason is because guitar amps are midrange amps and speakers rarely produce any frequencies below 100Hz or above 6Khz. Where you hear the difference in tubes is with high end Hi Fi gear where the super highs and lows are heard. There you can hear the transparency much better but a guitar producing most of the frequencies between 500~4Khz, the bandwidth is just so limited the differences in tubes just can't be appreciated much.

    Tube bias for the power tubes can make a difference. Some tubes have higher milliamp ratings and you can bias many amps up do they drive cleaner or break up easier. Some Voxes use class A circuitry and are a bit different than an A/B amp when it comes to drive. I wouldn't experiment much with biasing them hotter or cleaner. The old Voxes used to blow up regularly because tubes changed value over time and the circuitry design was pretty poor. I believe some of those flaws have been fixed in reissues but there's no sense in tempting fate.  


    • Brian May
      Brian May commented
      Editing a comment

      I've got JJs in my AC30HW2X...and they sound great. Now, JJs are known for being darker sounding though so if your wanting chime n sparkle then they may not be the best choice...but that said they sound bright enough to the top boost channel isn't exactly short on top end in its sound anyway. What I did notice when i revalved mine was the new valves most definately had more distortion to valves can be rated and selecrted on how early they break up. Whislt not actually buying and asking for some that break up early I wasn't compaining when I found the ones I got did so! As AC30s are mad loud getting some breakup sooner rather than later is a good thing in my view! If your amp has had its valves in 3yrs don't wait for 'em to blow/fail...power valves usually take down the rectifier with 'em when one goes down.


      AC30s are notoriously hard on valves and they don't live happy in there for 3yrs if the amp is getting much regular useage...they run hot all the time even if your not playing loud - they just like to eat EL84s so they degrade their sound over time..a bit like guitar strings. My last valve change came a few months ago. I'd had the amp 18months and had no idea how old the valves were in it when i'd got it 2nd hand so when i started getting an annoying rattle it was time. But nice suprise in that the new valves sounded better and had earlier breakup and consequently more dirt when fully cranked. If you stick with your tired old valves you'll always be wondering when one is gonna blow and let you down and also wondering how much better your amp might sound with a new full set of valves in get 'em changed. You know it makes sense.

    • Mark Secrist
      isitnormal? commented
      Editing a comment

      Do you like this product?VOX-BrianMay.jpg

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    • albano1973
      albano1973 commented
      Editing a comment

      went with 1 V1 JJ longplate ECC803S  V2 and V3 JJ ECC83s 

      putting them in now