Vox AC30CC Re-Tube Question

Discussion in 'Amps and Cabs' started by grateful.ed, Dec 24, 2009.


  1. grateful.ed

    grateful.ed Member

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    One of the online tube retailers has upgrade packages for lots of amps and I'm looking at the 2 options for my AC30CC.

    One has the Russian EL84M / 6P14P-EP and Sovtek 5AR4 / GZ34, and,
    the other JJ EL84 and JJ GZ34 / 5AR4.

    Both packages have Tung Sol 12AX7's.

    Does anyone have any experiences with these set ups?

    My initial thought was to go with the JJ's since Voxes are tough on tubes and JJ's seem to be able to take a beating, but the packages cost about the same so I'm wondering if I should consider the other option.

    Any thoughts/comments or other options/suggestions are appreciated.
     
  2. Diggy

    Diggy Member

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    I submitted this same question about 2 days ago, and several people recommended JJ's. I already had some faith in JJ's after retubing my old HRDx, so that is what I ordered.

    Several people also suggested Eurotubes as the place to go for JJ's.
     
  3. Steve73

    Steve73 Member

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    Yeah, the JJ pack all the way. The JJ EL84's are darker, a plus with an AC30 IMO. The JJ GZ34 is a good, tough rectifier too, which it has to be with the AC30.
     
  4. grateful.ed

    grateful.ed Member

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    Thanks for the feedback.

    I did some research as well and at this point the only concern I have with JJ tubes is the rectifier....it sounds like they are prone to failure in general.

    Since the rectifier seems to be the main problem with these amps,

    Has anyone had problems with a JJ rectifier in an AC30CC combo?
     
  5. utterhack

    utterhack Gold Supporting Member

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    The problem isn't the tube, it's the circuit. The amp is designed to fry rectifier tubes. (This is true for some other AC30 versions as well.)

    Fortunately there's an easy fix.

    1. Turn amp on and play for a while
    2. Observe the position the "STANBDY" switch is in
    3. LEAVE IT THERE AND NEVER TOUCH IT AGAIN
    4. Enjoy your trouble-free AC30

    a few relevant threads:

    Do Not Use Standby on an AC30: http://vintageamps.com/plexiboard/viewtopic.php?f=2&t=75667
    Vox AC30s: to use standby switch or not: http://www.vintageamps.com/plexiboard/viewtopic.php?f=2&t=80999&p=799182
    The Old Standby Switch Chestnut!: http://vintageamps.com/plexiboard/viewtopic.php?f=2&t=81689
     
  6. grateful.ed

    grateful.ed Member

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    utterhack....UR Kind.

    I've seen references to this and have tried to avoid hitting the stand by.

    I guess I'm making a mountain out of a mole hill, but this amp has been trouble free for so long and I've read so many AC30CC horror stories.
     
  7. utterhack

    utterhack Gold Supporting Member

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    In that case: JJ rectifier should be as good as any :aok
     
  8. stevewire

    stevewire Member

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    I like the JJ EL84s at least better than the factory stock EH EL84s that came with it. To me, they seemed to have more clarity.

    I tried some JJ 12AX7s in the preamp. In comparison to a few other brands, I felt that they had a louder volume, sounded fatter, but were real muddy and kind of dark. My AC30CC came stock with Tung Sol's in the V1 (normal channel) and V3 (phase inverter position), as well as a Sovtek 12AX7WC in the V2 (Top Boost gain stage). At this point, I am only really using the Normal channel. I felt that a Tung Sol 12AX7 in the V1 position had more clarity, high end, and gain; but less low end, less mids, less volume and were a bit harsh in the high as compared to the JJ 12AX7s. I even tried a long plate balanced gold pin Tung Sol 12AX7 ECC803s in V1. I've read that long plate ECC803s might not be so good in combos, due to microphonics. It lacked in gain, volume and low end. To my surprise, the tube I liked the most in V1 was a Chinese 12AX7A that I pulled from a 5150 that I bought in 1997. Compared to the few other tubes that I have, it had the best clarity, friendliest highs to the AC30CC, stronger gain than the JJ, less gain than the Tung Sols, better low end than the Tung Sols, more volume than the Tung Sols and less volume than the JJs.

    Out of those tubes, I liked a balanced, gold pin JJ in V3(phase inverter position). It seemed to make the tone a little more round than the other tubes.

    I still have the original Sovtek GZ34 rectifier tube in it. I don't use the stand by switch, and haven't noticed a problem with the rectifier tube.

    I definitely haven't drawn too many conclusions from this and intend to continue trying out tubes. I'd like to hear some more brands or types beyond JJs, Tungs Sols and Sovteks. Probably give NOS a try; although, I'm kind of cautious of this being a slippery slope with diminishing dividends.

    These are at least my impressions of what I have. I'm really interested in what others experiences are in this area.
     
    Last edited: Jan 27, 2010
  9. Thelastninja

    Thelastninja Member

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    Thanks for sharing, stevewire
     
  10. sixstring531

    sixstring531 Supporting Member

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    JJ El84s and Preamps and I prefer a sovtek in Rectifier slot -- I've blown 2-3 JJs, and two of those were less than a year old. These amps run muy hot, so having heavy glass is a plus.
     

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