Current JJ ECC83S test results

Discussion in 'Amps and Cabs' started by myles111, Jan 21, 2008.


  1. myles111

    myles111 Member

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    Current JJ ECC83S test results

    These are still the highest true gain 12AX7 tubes on average of current 12AX7 production types. A number of these had a gain of over 100 in a batch of 100 tubes tested.

    The typical preamp tube today has a measured gain of less than 85 and ranges of 70-80 are the average that are typically seen.

    This is just test data that is done on every run received from vendors. I am not saying this is good, bad, black, white, loud, quiet, right, wrong, etc. It is just data that I am putting up here for folks that can understand what this is showing and can use this information. I do not intend to explain what these columns mean. Either you know what these figures mean or you do not. If you do not then there are many good books out there that will give you a great foundation. One book that should be in every library of amp folks is a copy of the RCA Receiving Tube Manual. You can find these at www.tubesandmore.com and other sources.


    As a side note .... the second batch of ECC83S tubes from JJ in a group of 100 had an average gain of 94.6. This is about 10 points higher in average than any other current 12AX7 at the moment. There were over 15 tubes in the 100 with gain of between 99.9 and 107.6


    [​IMG]
     
  2. Dave

    Dave Member

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    How does the JJ ECC803S compare?
     
  3. myles111

    myles111 Member

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    I will post the test data on the 803S in the future but to leave you with a bit of info on that tube the gain falls in the middle of things today at 78-82 being the average. Very few tubes hit 90 and less than 10% hit over 85.
     
  4. Dave

    Dave Member

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    Thanks, Myles.

    So what are the benefits, if any, of a high gain pre amp tube?
     
  5. S.A.M.

    S.A.M. Member

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    I've got a couple from dougstubes rated at 110
     
  6. myles111

    myles111 Member

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    Well, for one thing it is not "high gain" as much as it is design spec gain that is rarely reached anymore.

    If an amp was designed around a spec 12AX7 using a proper gain tube will help the amp sound as it was designed.
     
  7. myles111

    myles111 Member

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    That is not true gain but is some generic number of some sort. The VTV tester does not measure true / actual gain. It's "gain" scale just allows one to compare tubes in one fashion and find tubes that are stronger or weaker than others. The VTV gain scale does not coralate with actual gain which takes mutual transconductance and plate resistance into consideration.

    This is not a complaint on the VTV tester ... it is a nice device but at $700 or so will never compare to something such as an RCA WT-100.

    If you are ever in So Cal and would like to know what those "110" tubes actually are doing let me know and I can test them with you while you watch and print out the test results.

    As a side note .... the second batch of ECC83S tubes from JJ in a group of 100 had an average gain of 94.6. This is about 10 points higher in average than any other current 12AX7 at the moment.
     
  8. Dr. Jimmy

    Dr. Jimmy Member

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    That's great and all, but why do so many people complain that they sound dark or flat in their amps?
     
  9. 110db

    110db Member

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    O.K. sounds great, but where can I buy them and be assured of this gain of over 100?
     
  10. Rick1114

    Rick1114 Supporting Member

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    My amp (bought 2nd hand) was outfitted entirely withh JJ's from Eurotubes. I didn't mind the attenuated treble so much (in fact I desired less treble), but the JJ83S without a doubt have less dynamics and touch sensitivity than any other new production 12AX7 I've tried in V1 or V2, so they pretty much all go unused now in my amp!
     
  11. blues

    blues Supporting Member

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    Ive had the same trouble with thier el84"s and the 12ax7. They were in an Aiken Invader and a marshall 1974x that I had. I ran those amps dimed all the time. The power tubes were just about shot after a few months in both amps. I did notice the 12ax7's sounding flat. I ended up retubeing both amps. Thats just my expirence. YMMV
     
  12. Rod

    Rod Tone is Paramount Silver Supporting Member

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    It really depends on the amp design....In some of my amps, JJ's sound unreal...in others, very flat and dull...
     
  13. Rod

    Rod Tone is Paramount Silver Supporting Member

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    I forgot to mention....THANKX Myles for publishing these test results!!!
     
  14. The Pup

    The Pup Supporting Member

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    Too bad there isn't an empirical "tone" measurement test.
     
  15. honduras

    honduras Supporting Member

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    The JJECC83S preamp tubes and EL84 power amp tubes totally transformed my Marshall JCM 201 from a thin sounding fizzy amp to a warm smooth vintage toned monster which I was absoluely thrilled with.
     
  16. myles111

    myles111 Member

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    You are welcome
     
  17. myles111

    myles111 Member

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    I sort of think there is .... your own ears :) If you are happy with the tone then it really doesn't matter much at all what numbers or specs tell you in the end.

    The nicest Fender Tweed Champ I ever heard had a Telefunken in V1 (it's only preamp tube). One side tested virtually dead and the other side of the tube tested about half of what a new tube would test. In the amp it sounded spectacular. Maybe with less gain the cute little amp had more headroom? Maybe it was pushing the output tube less than expected? I am not sure other than it was the coolest Tweed Champ I ever heard that was box stock.

    So ... in the end your own ears are the best tool to use.
     
  18. myles111

    myles111 Member

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    I think you put this in the wrong place.
     
  19. stuffedshirt

    stuffedshirt Member

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  20. Roccaforte Amps

    Roccaforte Amps Member

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    Doug's Tubes. who I use.
     

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