Durable current production EL84 ?

Discussion in 'Amp Tech Center' started by dougstrum, Mar 20, 2018.

  1. dougstrum

    dougstrum Tele-Holic

    Posts:
    902
    Joined:
    Oct 6, 2015
    Location:
    blu ridge mtn cabin
    Time for the Pro Jr to get new tubes. The old ones were Sovtek and held up well,
    but the amp is starting get dirty pretty quick. Seems I went through several pairs
    before finding some good ones last time.

    I've got a quartet of Fender/Groove Tube/Sovtek in parts drawer and tried them out~
    2 are way microphonic. Tried the other 2 and one makes a sound like clinking glass on
    warm up and shut down, doesn't make me feel very confident.

    Are there any real differences in reliability with current production EL84's?
    Seems Sovtek or Chinese are the available choices with various rebranding.
    Any consensus toughest EL84 available?
     
  2. john_cribbin

    john_cribbin Tele-Afflicted

    Posts:
    1,227
    Joined:
    Nov 26, 2014
    Location:
    London
    JJ's are well known to be rugged in the EL84 format. Sound good as well.
     
    awasson, clintj and zook like this.
  3. nojazzhere

    nojazzhere Poster Extraordinaire

    Age:
    67
    Posts:
    8,188
    Joined:
    Feb 3, 2017
    Location:
    Foat Wuth, Texas
    If Sovteks were good before, why not go with them again???
     
    bftfender likes this.
  4. dougstrum

    dougstrum Tele-Holic

    Posts:
    902
    Joined:
    Oct 6, 2015
    Location:
    blu ridge mtn cabin
    It was a couple years ago and I went through a few sets of
    Sovtek before I had a good pair...

    Perhaps I should give JJ's a try.
     
  5. slider313

    slider313 Tele-Afflicted Silver Supporter

    Posts:
    1,134
    Joined:
    Jan 6, 2011
    Location:
    NC
    The new Tung Sols are built well and sound warmer than the JJ's, if that's what you're looking for.
     
  6. clintj

    clintj Friend of Leo's

    Posts:
    4,919
    Joined:
    Apr 4, 2015
    Location:
    Idaho
    I'm on my fifth or so pair of JJs now with no issues, including one amp that really pushes them hard.
     
  7. misterdontmove

    misterdontmove Tele-Meister

    Posts:
    300
    Joined:
    Mar 25, 2011
    Location:
    Connecticut
    My personal favorite! Although they are "glassy" and I find them high mid voiced. I use them in an AC15 so that may be a different sound than you're seeking. I tried the Sovtek el84M an they were big and round. Lots of bottom and not as bright in my Vox. They may work well in your Fender.
     
  8. Inglese

    Inglese Tele-Meister

    Age:
    40
    Posts:
    107
    Joined:
    Mar 7, 2018
    Location:
    Italy
    I usually go with Tungsol.
    I find them easy to match and reliable; a had a couple running at 19W idle for a couple of month in a project of mine!
    However I suggest you to have the bias properly set.
     
  9. dougstrum

    dougstrum Tele-Holic

    Posts:
    902
    Joined:
    Oct 6, 2015
    Location:
    blu ridge mtn cabin
    Just read a few descriptions of Sovtek EL84M, supposed to
    be really rugged! A bigger bottom end and not quite as bright
    might just suit the Pro Jr~
     
  10. FMA

    FMA Poster Extraordinaire

    Posts:
    5,351
    Joined:
    Apr 29, 2003
    I've had a set of JJs in my AC15 for years now and they're holding up well and sound good, and AC15s are tough on power tubes, I'm told.
     
  11. ICTRock

    ICTRock Tele-Afflicted

    Posts:
    1,390
    Joined:
    Jul 31, 2014
    Location:
    Tampa,FL
    I like the telefunken black diamonds I put in my homebrew marshall 1974
     
  12. schmee

    schmee Poster Extraordinaire

    Posts:
    7,071
    Joined:
    Jun 2, 2003
    Location:
    northwest
    I had great luck with JJ's in my Z amps. No longer have them though. I have several JJ's out there with minimal use, and a new quad of those soviet (different number/compatible to EL 84's) that were the rage a few years back out there collecting dust.
     
  13. SPUDCASTER

    SPUDCASTER Poster Extraordinaire Silver Supporter

    Posts:
    7,645
    Joined:
    Sep 7, 2010
    Location:
    Grangeville, Idaho
    I go to Eurotubes for my JJ's. Haven't been disappointed so far.

    I am using a Tungsol 12AX7 in my AC15 for the V1.

    Might try the Tungsol EL84's at some point. They seem to get good reviews.

    Not much difference of a price point.
     
    Last edited: Mar 20, 2018
  14. Tenderfoot

    Tenderfoot Tele-Meister

    Age:
    73
    Posts:
    462
    Joined:
    May 8, 2014
    Location:
    Katy, TX
    Just retubed my Blues Jr. III with a set of Ruby EL84CZ Premium Matched for $21.99 with 2 day free shipping from Musicians Friend (shipped to TX there was no tax). They are rebranded JJ's according to my Google research. They have a slight edge sound wise with more bottom end than the Groove Tube El84's that came with the amp (five years ago).
     
  15. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,848
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    The Pro Jr is biased very hot from the factory. I have witnessed 100% of max 0late dissipation, which is high for fixed bias, and this amp is fixed bias. I old suggest having bias adjustment done...preferably with a bias pot added to the circuit. If you do not want to do that, buy some ‘cold’ tubes.
     
    Chicago Matt likes this.
  16. rob2

    rob2 Tele-Holic

    Posts:
    646
    Joined:
    Apr 25, 2009
    Location:
    Cork,Ireland
    JJ...best cost/quality/sound mix around.....European made too,I think they are our last large scale valve maker....
     
  17. maj34

    maj34 Tele-Meister

    Posts:
    282
    Joined:
    Nov 19, 2013
    Location:
    Calgary
    I did a lot of experimenting on my Vox AC15C1 - this amp runs the tubes pretty hot.

    I noticed the JJs would red-plate ever so slightly - but in a dark room you could clearly see red-plating. Then I tried Electro-Harmonix EL84s and I didn't get any red-plating. Not very scientific, but nonetheless, there was a very clear qualitative difference in my experience. Also, the EH tubes were also clearly thicker plates and thicker glass.
     
  18. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,848
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    That Vox is cathode biased versus fixed bias of the little Fender. However, there is every possibility...and likelihood...that you had some EH tubes that had 'cooler' performance parameters than did those particular JJ's. You could just as well have noted the same situation if you had had two sets of EH tubes that were very different in how they worked in circuits. That is the advantage of the grading systems that distributors use....one can maintain a bias situation from one set of tubes to the next by buying tubes that are matched...have the same performance parameters...from one st to the next.
    In other words, that redplating by the JJ's is not indicative of how all JJ EL84's operate, and the non-redplating of the EH is not indicative of how different EH EL84s perform, either.
    That is also why I do not consider cathode biased amps to be plug and play IF the player is discerning.
    I tested some NOW RCA 6V6GTY's in a cathode biased Champ amp just to see if I could get some matched pairs. NO way...not a pair to be made out of about 13 tubes. I saw widely varying plate voltage numbers, and I saw plate dissipation numbers ranging from 80% to 150%. I also did not see any redplating in that tube that was dissipating 150% of MPD in that cathode biased amp. IT is of value imho and ime to take note of biasing numbers even in cathode biased amps/circiuts so that one understands what is going one and how to either maintain that or change it.
     
  19. maj34

    maj34 Tele-Meister

    Posts:
    282
    Joined:
    Nov 19, 2013
    Location:
    Calgary
    Hi Wally. I think it was actually the other way around. The JJs were cooler tubes and the hotter EH tubes still had less red-plating. I tried 3 sets of JJs in this AC15 and all them red-plated.

    Back when I was messing with the EL84s I discussed this with someone at The Tube Store. They have that "Perfect Pair" system for tube matching, and this concept ties in with what you mentioned.

    As best I can tell, they just have a tube tester (maybe even just an amp). They put tubes in that known piece of kit and measure the resulting bias. If it's 51mA they call that tube a "51".

    The qualitative experience I performed above was with JJs that were a "34", another set of JJs that were a 50, and EH tubes that were a "51". Both sets of JJs red-plated and the much hotter EH tubes did not.

    I'm not 100% sure of what I'm talking about here - not a tube guru - but the above makes sense to me, and would seem to indicate the EH tubes are much more robust than the JJs.
     
  20. Chicago Matt

    Chicago Matt Friend of Leo's

    Age:
    70
    Posts:
    2,736
    Joined:
    Aug 23, 2014
    Location:
    Woodstock
    +1 on making the bias adjustable with an added bias pot. So glad I have it on my PJ III.
    Here is a link that shows how to do it:
    http://billmaudio.com/wp/?page_id=916

    Finding 12ax7's for the preamp that aren't noisy in the PJ has been more of a challenge for me than finding good sounding power tubes. Probably just luck but I ended up with some old Groove Tubes 12ax7's that came with my old Blues Deluxe, and they are much quieter than the JJ's or Sovteks that I tried. They sound good too.
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.