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Thread: Groove Tubes

  1. #1
    Forum Member brianf's Avatar
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    Groove Tubes

    Which Color Groove tubes (6L6) break up quicker. Red or Blue?

    Thanks

    brianf
    Oh Man!!! I never knew Fender made amps too!!!

  2. #2
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    Tim C.'s Avatar
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    Brian,

    Did they change their numbering system and go to colors?

    I thought they were numbered 1 through 10 with 10 being the cleanest and 1 the dirtiest.

    I know Fender uses Groove Tubes in a color rated system for their Blues DeVille amps. Is that what you are talking about?

    If so, that has to do with Fender's biasing system on those amps.

    Tim C. :)

  3. #3
    Forum Member brianf's Avatar
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    I think they have them really fine tuned now. There are 30 different ratings. Red, Blue and White each have a 1 to 10 rating. I could very well be wrong though! I was in a store yesterday and saw blue ones rated 5 and 6 and red ones rated 1 and 2. They couldn't tell me the difference.

    I know white is in the middle (mine are white 7's 6L6.)

    I went to Groove tubes site but there is not too much on tube ratings there.


    I'll keep digging. They do have a good write up on there new USA built tubes.

    brianf
    Last edited by brianf; 11-24-2002 at 11:16 AM.
    Oh Man!!! I never knew Fender made amps too!!!

  4. #4
    Forum Member Stealth's Avatar
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    I don't know if this can help but i got a copy of Frontline(Fender) and at page 166 they talk about Fender Groove tubes,i'll type what it is written!

    "All Fender tube amps now come "factory equipped"with Groove tubes.They are much easier to replace(no rebiasing needed when replaced with color-coded sets),they have improved harmonic balance,longer lifespan,matched gain to distortion ratio plus a wider frequency response."

    That's it!

  5. #5
    Forum Member Teleologist's Avatar
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    Only problem is, for the price they typically charge you can often get NOS tubes or the same(or better) current production tubes matched & graded from someone else for quite a bit less.

    The article that compared the new GT 'GE' 6L6 to a NOS version was pretty interesting. I was a bit confused about the 'internal construction differences', as I have some NOS GEs on the shelf and.... . I guess I'll just have to see one up close and personal, but that's not very likely at $90/pair or even 40% off.

  6. #6
    Forum Member brianf's Avatar
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    I have to agree with you Teleologist. Svetlanas are less money and are probably better. Thats what I have in the amp now. I also have the brand new set of White Grooves that came with the amp. I wanted to get a couple of sets of the Groove Tubes to experiment with. I have someone who can do the re bias. We are going to do an A vrs. B kind of test on a HR Deville. I just forget if its the reds or blues that break up easier.

    To Stealth. Thanks. I also looked at the Fender website but not much info there.

    brianf
    Oh Man!!! I never knew Fender made amps too!!!

  7. #7
    Forum Member Teleologist's Avatar
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    A guess would be that reds run hotter and therefore would break up quicker.

    FWIW, if you are able to easily re-bias, all that grading systems do in terms of sound for a particular type/brand tube is the equivalent of running the amp with one pair of the same tubes at different bias settings. Bias a set of tubes hotter(more current) and the sound will be fatter with quicker breakup. Bias colder and the sound will be thinner and brighter with more headroom. There are limits of course and you can't bias a half-dead or un-healthy tube to sound right, but all they're really doing is picking tubes to get the amp to run at a certain level, rather than adjusting the amp to run the tubes at that level. Nothing wrong with that approach, just a different way to get to the same place that's much easier for some to deal with.

    Try measuring the current of a #7 or 8. Then stick in a #4 and rebias to the same current....

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