Vox ac15 tubes

Discussion in 'Ampage Area' started by mbkri, Jan 19, 2021.

  1. mbkri

    mbkri Country Gent

    Sep 22, 2012
    Chicago
    Real simple question.... probably no simple answer:
    My Vox ac15 c1 has a slight fizzy faint echo going on recently which i think is a microphonic power tube.
    Anyhow ive played this thing for 10 years and it could do with a new set of tubes im sure. It sounds good..... but i bet it used to sound better.
    so..... what do y’all recommend?
    I dont want to spend more than $150.
     
  2. Henry

    Henry I Bleed Orange

    Apr 9, 2014
    Petaluma
    Well, you should probably have a set of backup tubes anyway, so I would order a full set of your tubes of choice, then roll tubes and see what happens
     
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  3. ZackyDog

    ZackyDog Friend of Fred

    Age:
    56
    Feb 6, 2015
    In the USA
    If it's a microphonic issue, it's usually a preamp tube. Replace the preamp tube closest to the input jack.

    I use JJ ECC803S and JJ EL84s. You can get them from Eurotubes.
     
  4. Tony65x55

    Tony65x55 Gretschified

    Age:
    64
    Sep 23, 2011
    The 'Shwa, Ontario, Canada
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  5. rockinforJesus

    rockinforJesus Synchromatic

    972
    Nov 7, 2014
    Upstate New York
    I took @ZackyDog ’s advice years ago and went with the JJ’s. Very good choice IMHO.
    I put a matched pair of power tubes in, along with 2 balanced ECC83 preamp tubes, and an ECC803S long plate tube in the V1 position. You can read about them here: https://www.eurotubes.com/store/pc/preamp tube descriptions.htm .
    Also if you are interested, I found a great resource for the AC15 info: http://www.voxshowroom.com/uk/amp/ac15c1_hood.html.
    Also, do yourself a favor while you have the back cover off and replace the stock reverb tank with a Mod tank. You’ll thank me later.

    457A07CE-DDA0-45A8-9C07-F9AE5DDF89BA.jpeg
     
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  6. Jelly Roll Horton

    Jelly Roll Horton Country Gent

    Nov 10, 2017
    Portland, OR
    I also took Z-Dogs advice and went to Eurotubes. Very nice, knowledgable, helpful guys, and their prices are very fair. I highly recommend them.
     
    Last edited: Jan 20, 2021
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  7. ZackyDog

    ZackyDog Friend of Fred

    Age:
    56
    Feb 6, 2015
    In the USA
    Nice that they're in your neighborhood, Ray.
     
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  8. Jelly Roll Horton

    Jelly Roll Horton Country Gent

    Nov 10, 2017
    Portland, OR
    Very convenient. They even offered to test my old tubes at no charge.
     
  9. Bertotti

    Bertotti Friend of Fred

    Jul 20, 2017
    South Dakota
    Not a JJ fan. I still prefer eastern block tubes.
     
  10. ZackyDog

    ZackyDog Friend of Fred

    Age:
    56
    Feb 6, 2015
    In the USA
    Initially, I wasn't either.

    Their ECC83S sounded like mush in my VOX Top Boost amps. Then I read about the ECC8O3S; I tried it and it was a match made in heaven. And their EL84 power tubes can withstand the high VOX voltages and, have a vintage, Telefunken-like sound.

    [​IMG] upload_2021-1-21_2-0-28.jpeg
     
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  11. Bertotti

    Bertotti Friend of Fred

    Jul 20, 2017
    South Dakota
    I have not tried all of their tubes. I still have a few in my tx head but I have had more fill in a few years then any other that I tried so I stopped using them. Probably just coincidence I see the little Typhoon came with one in it so perhaps they QC has been stepped up or I just had an unlucky batch it does happen. I really do like the Gold Lion pre tubes @TV the Wired Turtle turned me on to but they were expensive so I only have two. I will have to try the ECC803S is it an AX 7 variant? When I think about it at the time of the failures all I had were 6l6 amps and it was the 6l6 that kept failing. Sadly one quad only had maybe 20 hours on them and after loosing a few components in one head I trashed all four. Really liked the Sovtek WXT tubes in that head. Now some EH. My go to EL 84 in the NightTrain are some 6n14p Eastern block tubes. The one I currently use is a bit noisy when not being played and that could be a pre tube acting up but once you start playing it is so rich harmonically I don't want to mess around until one fails. So many tubes so little cash to try them all. Come on Mega millions! hahahaha Truth is in the last four or five years I haven't gotten a dud tube. I'm sure some are out there but I think the current production tubes are doing a much better job of QC. 2006-7 it seemed there were more marginal tube floating around even from some well know brands. Or is it just me?
     
  12. ZackyDog

    ZackyDog Friend of Fred

    Age:
    56
    Feb 6, 2015
    In the USA
    I will have to try the ECC803S is it an AX 7 variant?

    Yes, it's a 12AX7-type tube. I like it better than ANOS Mullard, ANOS Telefunken and Ei (Yugoslavian), as well as other new production tubes.

    I really do like the Gold Lion pre tubes


    I've read some great things about Gold Lion. Unfortunately their EL84s purportedly do not hold up well in VOX amps.

    @Bertotti
     
  13. Bertotti

    Bertotti Friend of Fred

    Jul 20, 2017
    South Dakota
    I have only tried the pre amp tubes and they were not the made in China ones. I paid more for the made in Russia ones. I suspect the made in China are just off the same line as other manufactures tubes.
     
  14. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    Maybe I've just not run into this, but a faint echo doesn't sound like a bad power tube to me. Maybe the fizz, but not the echo.

    Power tubes usually either burn up all of a sudden and take a resistor with them, or they start getting static and you see sparks inside, or they get very weak and hardly have any output. If you tap on a power tube with a chopstick and it causes static or sputtering noises, that's a good indication you have a problem. Power tubes should be quiet when you do that.

    Here is a good guide:

    https://mesaboogie.zendesk.com/hc/en-us/articles/216599018-How-can-I-troubleshoot-tube-issues-
     
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  15. Sid Nitzerglobin

    Sid Nitzerglobin Country Gent

    Jun 8, 2015
    fROMOHIO
    I've generally liked the EL84Ms from Sovtek best in the amps that take them. More of a mixed bag on the pre tubes but the New Sensor Mullard CV4004s have been cool for me in the primary gain stage(s) of the Voxen/Marshalls w/ Sovtek 12AX7LPS for the PI.

    .02
     
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  16. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    If you can find NOS or ANOS EL84 tubes for a reasonable price, I really like those best. I have a couple of sets of RCA ANOS tubes that I used in my Laney that are really nice. But unless you can get them for a reasonable price, it's not worth it. I got mine when the getting was good.
     
  17. mbkri

    mbkri Country Gent

    Sep 22, 2012
    Chicago
    Well i quickly realised that there are tube connoisseurs out there in the forum and im certainly not one of them. How do you all keep track of this stuff and make comparisons? Are you sitting on a stack of good tubes and doing a/b comparisons? i decided to go with Eurotubes and their standard recommendation for the AC15 and i have a set of EL 84s and EC 83S winging their way to me. I got the euro dampers too which i hope will assist in further minimizing atmospheric noise in my home studio for recording purposes.
    Thanks for all the help and recommendations.
     
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  18. mbkri

    mbkri Country Gent

    Sep 22, 2012
    Chicago
    More like a ghost, a faint fizzy memory of the note.
    Tapping on the power tubes they sounded very different pitches but similar volumes. Im replacing the whole set just to see what i see. Im probably used to the amp sounding way worse than it did years ago.
     
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  19. ZackyDog

    ZackyDog Friend of Fred

    Age:
    56
    Feb 6, 2015
    In the USA
    I have gradually tried out new preamp and power tubes over the years. I make mental notes as I go along. When I hear the "right" sound, I stick with it.

    De nada :)
     
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  20. Gretschtim1

    Gretschtim1 Country Gent

    Dec 4, 2012
    Dundalk, Md
    I generally don't change the 12ax7 tubes in my amps until they present a problem. Especially when they are very quiet and powerful. Some of my preamp tubes have been in service for 30+ years. The ones in my Ampeg Gemini I are 56 years old and still sound great - Super quiet and punchy. Changing them for new ones did not improve the sound so I put the original ones back. It's hard to find good sounding preamp tubes that work good in every amp. Sometimes what sounds good in my Fender amps don't cut it in my Marshall amps. Power tubes - EL84 type - I've been using Sovtek in my AC 30 and AC 15 since the early 90s. I pitched in and bought 144 of them with a friend back in 94. They sound really good and hold up well. I think we got them for $2.00 a piece back in 94...:). I also though there'd be a tube shortage so I stocked up...:). For a while I was re-tubing my 2 AC 30s and my AC 15 every 6 months because I was using them about 40 hours per week. I haven't changed them for about 5 years because when I swapped them out with new ones they sounded the same - they still sound fine to me. I guess I should try changing them again just to see if the sound changes. That supply of Sovtek EL84s I bought back in the 90s has gotten down to a few sets.
     
    Last edited: Jan 24, 2021
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