Never thought I would hear a difference ...

Discussion in 'Glowing Bottle Tube Amp Forum' started by TheDams, Feb 21, 2020.

  1. TheDams

    TheDams Tele-Meister

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    Today, I did some tube rolling in my EarFuzz 5W (based on a GA5): I swapped between rectifiers (5Y3), something I don't remember ever trying, because for me a rectifier is just here to convert/give juice to the amp :)

    I remember having a Bendix 6106 (almost never used it, bought it years ago when they were decently priced) somewhere in my NOS tubes stash.

    I swapped between the GE 5Y3GT that I had in the amp since a few months, and the Bendix.
    I swear I can hear a better/tighter bottom end, and it seems that the amp is a tiny bit louder, using the GE.

    I did the swap maybe 10 or 12 times to be sure I really heard a difference, and, for the life of me, I did !

    I would have never thought there would be a difference between rectifiers !

    What say you, oh tube amps gurus ?
     
    Last edited: Feb 21, 2020
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  2. schmee

    schmee Poster Extraordinaire Silver Supporter

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    I say unless you rebiased to be exactly the same when you swapped, you dont know it was the tube. :>)
     
  3. TheDams

    TheDams Tele-Meister

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    It's a single-ended (6sj7, 5881, 5y3)... so no bias (from what I know about SE amps ;) )
     
  4. MuddyWolf

    MuddyWolf Tele-Meister

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    Naw I dont believe it. I've never tried myself but everybody on the internewt knows these fringe ideas are wrong.
     
  5. muchxs

    muchxs Doctor of Teleocity

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    I say measure supply voltage.
     
  6. TheDams

    TheDams Tele-Meister

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    I guess the slight difference in tone/volume comes from the fact - as I read somewhere - that a 6106 has a slightly different voltage drop than a “regular” 5Y3gt ?
     
  7. TheDams

    TheDams Tele-Meister

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    I am not trained in tube amps electronics :oops: (even if I know my safety rules in a tube amp and some basic maintenance, and know enough in the use of a DMM).
    Where/how do I measure that ?
     
  8. muchxs

    muchxs Doctor of Teleocity

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    Clip your black lead to the chassis. Using one hand measure voltage at Pin 8 of your 5Y3 (or 6106). Poke Pin 8 with the probe on your red lead.
     
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  9. TheDams

    TheDams Tele-Meister

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    Thanks muchxs... I will measure if I have an opportunity to open the chassis.

    for now, I’d say my post was more out of curiosity than anything else. I am just surprised to be able to actually hear a (slight) difference in low ends “tightness “/output.
    But as I said, I read somewhere that 6106 have slightly different characteristics than your standard 5y3.

    Correct me if I’m wrong.
     
  10. Nickfl

    Nickfl Tele-Afflicted

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    All amps have bias, just because you don't have to adjust it when changing tubes doesn't mean that it isn't a thing or that it stays the same. Cathode biased amps are self-regulating (up to a point) but different tubes are almost certainly going to be at somewhat different bias levels due to changes in current draw and plate voltages, which is at least part of the difference people hear between different brands of power tubes.

    In this case, even though you only changed the rectifier I'm sure your voltages are different, possibly by a significant amount, and chances are that is what you're hearing.
     
  11. TheDams

    TheDams Tele-Meister

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    Thanks for the explanation Nickfl ;)

    How fun, Bendix tubes (6106, or their 6v6 5992 ) are praised in a lot of places, but in that case, I actually prefer the much cheaper GE :D... price and fame are not always THE truth :rolleyes:
     
    Last edited: Feb 21, 2020
  12. robrob

    robrob Poster Extraordinaire Ad Free Member

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    As muchxs said, using a different type rectifier can change the amp's operating voltage and voltage sag, both of which can affect the amp's tone, playing dynamics and loudness.
     
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  13. gusfinley

    gusfinley Tele-Holic

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    If you can hear the difference, then put the one you like the most in there!

    Don't let anyone tell you differently.
     
  14. TheDams

    TheDams Tele-Meister

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    That is the first thing I did ;)
     
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  15. slider313

    slider313 Tele-Afflicted

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    The Bendix 6106 is an overbuilt 5Y3 and they take a good 45-50 seconds to warm up. They also don't produce the sag you would get from most other 5Y3's. The GE may be dropping more voltage and raising the current.
     
  16. Askwhy

    Askwhy Tele-Meister

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    The tech guys (though correct) are missing the simple fact that changing that tube, without rebiasing etc, absolutely does change the sound and feel of the amp. So what if making everything else the same would nullify or reduce the effect, the point is you don't HAVE to. If you hear a difference, there is one and and an easy one to get and change between those two specific tubes. Enjoy!
     
  17. FenderLover

    FenderLover Poster Extraordinaire

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    That's a good point, but I'd suggest that maybe non-tech guys might come to think the difference is the 'sound' of a different rectifier, and less about of the changes it may have caused. For instance, some people stick a 12AU7 in the first preamp position and complain about how bad a 12AU7 sounds.
     
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  18. slider313

    slider313 Tele-Afflicted

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    The GA-5 is single ended.
     
  19. Commodore 64

    Commodore 64 Friend of Leo's

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    Not saying you can't hear a difference at all. It's a bit of semantic argument. The rectifier tube is not in the signal circuitry. It's not affecting the signal. It can't.

    But...

    The operating points of every tube in that amp are set by a relationship with the plate voltage, cathode voltage, screen voltage. If that rectifier tube changed the B+ voltage, it changed every other voltage (and operating point) in that amp. So yeah, totally possible you hear a difference.
     
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  20. robrob

    robrob Poster Extraordinaire Ad Free Member

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    The rectifier creates the signal base. A tube amp really is a modulated power supply so a change in rectifier output voltage directly affects the signal, especially the power tube output signal.
     
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