Going from a GZ34 to 5Y3 in a 5E3

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Byrdseye, Nov 18, 2005.

  1. Byrdseye

    Byrdseye Supporting Member

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    How's that for alphabet soup! I just aquired a 5E3 Clone and it is a modded version that is able to use 6L6's and a GZ34 recto. My question is.........can I swap in the stock 5Y3 rectifier tube, check the bias and be good to go? (with 6V6's).
     
  2. TheAmpNerd

    TheAmpNerd Member

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    Hell yes!

    You also might consider the following:

    5Y3 with 6L6s
    GZ34 with 6V6s

    With the above that gives you four
    optioins.

    Check the bias and go with what
    works for you.

    Have fun and keep us informed.
     
  3. Byrdseye

    Byrdseye Supporting Member

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    Cool, Thanks!:cool:
     
  4. Wakarusa

    Wakarusa Member

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    I'd advise against both of these trials.

    The current draw from correctly biased 6L6 is right at (or above) the limits of what a 5Y3 will tolerate. Also, the voltage drop from the 5Y3 internal resistance (and resulting drop in B+) is so severe under this load that the amp becomes almost unusable (all distortion, all the time).

    Conversely, B+ will rise significantly with a GZ34/5AR4 and 6V6 installed. These amps traditionally run the 6V6 at or above published plate voltage specs, so the rise in B+ is just that much more beyond the spec. (and yes, I know that Deluxe Reverbs and others run 6V6 at 425VDC and higher)

    Options that are within spec and (IMHO) worth trying are 5U4 and 5R4 rectifiers with 6L6GC outputs. Both will pull B+ down and sag more than the GZ34 -- the 5R4 a bit more, the 5U4 a bunch more (but still all within spec). I personally prefer using a 5R4 here. A 5V4 may be worth trying also, but you need to be mindful of the current spec for the tube.
     
  5. Byrdseye

    Byrdseye Supporting Member

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    Thanks:cool:
     
  6. TheAmpNerd

    TheAmpNerd Member

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    Guys,

    Todd has a point with standard type 5Y3s.
    I'm spoiled, I have a stash of Bendix 5Y3s.
    These can take the pull of a 50 watt
    plexi type marshall with EL34s until about 9 on
    the amps volume knob! Not distorted all the
    time either (and this is EL34s!)

    That is pretty impressive and I've not blown
    one up yet. I've tried...shame on me.

    You probably won't have any problems in your
    little amp though, with good NOS 5Y3s just
    keep and eye on it, you'll know.

    Try it and see. If it ends up being that bad,
    just remove it and be happy.

    As for the GZ34 and 6V6, that should be one
    nice combination and a no brainer to do.
    More so then just the deluxe reverb too.
    Use good JJs or NOS RCAs
    and you will be very inpressed. Don't worry
    too much about the published specs, RCAs
    and JJs are more then up to the task.

    If you want to run the 6L6s
    I'd avoid the 5u4 as it is 3000 ma
    on the heaters. This combination with
    the 6L6s will definitely stress the power
    tranny. Don't know its specs (PT), but
    better to run a tube at or over limit
    then a power tranny.

    One last thought, if you really want the head
    room of a 6L6, plug in a solid state replacement
    rectifier and don't worry about it.

    With any of these trials, just check the tubes
    bias and when playing make sure they don't
    red plate on you and you should be fine.

    Experimentation is a good thing. You probably
    aren't going to blow anything up...but in the
    off chance you do it can be fixed pretty easily.
    We are talking a clone it's not a vintage piece.

    So in the words of some band who's
    name escapes me:

    "..take it, to the limit, one more time."

    Enjoy and let us know what you've
    discovered with your adventures.

     
  7. marcfrom

    marcfrom Member

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    Hi Guys

    I'm interested to swap my 5Y3 for a GZ34 rectifier and run with 6V6GT.

    There's no problems with OT transformer and filter caps ?

    Maximum voltage for Sprague filter caps is 475V.

    I can read something around 390V after the 5Y3 rectifier, it will be ok with a GZ34 ?
     
  8. phsyconoodler

    phsyconoodler Member

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    DO NOT USE A 5Y3 with 6L6's.You are asking for trouble.
    And usually an amp built to use 6L6's has a power and output transformer designed for those tubes.Switching to 6V6's presents a few problems.
    1)the voltage will be too high for proper bias
    2)the output transformer will have the wrong load and you will need to increase the speaker load.
    3)using a 5Y3 is not suggested with 6L6's because it's asking for premature failure.

    Unless you know what you are doing,don't be swapping tubes and rectifiers in that amp.You need to know what the specifications are before attempting it.
    Many amps use a 6.6k OT so you can make tube swaps like that without worrying about speaker loading.
    Don't just blindly stick tubes and rectifiers in your amp cause some guy tells you he's done it to his amp.His amp is not likely the same as your amp.
     
  9. rmconner80

    rmconner80 Cantankerous Luddite Silver Supporting Member

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    I agree, don't use a 5Y3/6L6s and don't use GZ34/6V6s in a 5E3.

    The reason is not so much plate voltage, it's the plate current at x plate voltage. A lot of 5E3s are already running the 6V6s at 90%+ plate current at their given plate voltage with a 5Y3; putting in a GZ34 will substantially raise your B+ and exceed max plate current. Depending on the voltage rating of your filters and the rating of your B+ you may also run into issues although this is unlikely.

    If you want the sag (or lack thereof) of a GZ34 you should use a lower B+ transformer and / or a larger cathode resistor.

    If you just want a stiffer rectifier check out a 5V4; however be prepared to swap the cathode resistor and / or make sure your tubes are not exceeding reasonable plate current specs at the new voltage.
     
  10. Trout

    Trout Member

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    :agree 1000%

    Tubes are not plug & play simply because they have the same pin outs.

    Often on lower B+ stuff guys do this knowing they are now off correct spec, but there are limits.

    I would contact the builder and get the specifics on the amp, (transformers) before even thinking about a potentially component damaging change.
     
  11. marcfrom

    marcfrom Member

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    The builder it's me.

    I build it on the original 5E3 Schematic with Mercury magnetics transformers (power and OT).

    I would like my amp sound like this:

    Crema wheat:

    http://www.tungstenamp.com/amps.htm

    http://www.youtube.com/watch?v=3X1AOlkabwo

    This amp have :

    1X GZ34 rectifier, 2X 6V6, 2X12AX7.

    So it's possible to modify a 5E3 to work with a GZ34, but i don't know what i have to change.
     
  12. marcfrom

    marcfrom Member

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    Does anyone know what componants i have to change to use it with a GZ34 ?
     
  13. Trout

    Trout Member

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    It is going to take more than tube changes to achieve that tone.
    You will need to mod the pre-amp to being similar to the 6G3 Brown Deluxe, This includes adding the mixer/divider resistors, addition tone pot (or dual pot & caps) Changing the plate load resistors on V1 as well as splitting/altering the V1 cathode bypass caps & resistors.

    If it were me, I would do the some of other mods first, then decide if you want to chase the tube's (rectifier, power & pre-amp)

    The million dollar question is can you play like that?
     
  14. marcfrom

    marcfrom Member

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    Have you the schematic for the modifications ?

    You talking about Brown Deluxe but Tungsten talked about 5E3 Tweed Deluxe.

    Of course i don't play like him, he play very well, but it's not the question because only him play like him !!

    I just looking for this amp tone.

    So if anybody can help or have the schematic of this amp...
     
  15. Trout

    Trout Member

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    nope, no schematics here, but its not hard to figure out with about an hour of web searches..
     
  16. marcfrom

    marcfrom Member

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    It's what i do searching some infos about it and i come on this forum.
    So if you have seen some infos please put the links.

    Thank you
     
  17. wyatt

    wyatt Member

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    1.) To the OP...if the amp biases up well with 5AR4/6L6GC it should fall right into the correct bias range for 5Y3/6V6GT. Typically, the difference in B+ voltage between the two rectifiers is just about right for the same cathode bias resistor value work in both setups.

    2.) To marcfrom, since you are getting 390VDC with the 5Y3, I doubt you could successfully bias the 6V6's cold enough with the 5AR4, no matter how much you fiddle with the cathode-bias resistor. And you certainly couldn't swap between the two without switching that resistor.

    3.) Also to marcfrom, the mod you are looking for is sold as the Mission Amps Tone/Volume Mod. It rewires 5E3 preamp to be more like a 6G3....the Volume controls are isolated from one another (no more interactivity), and the Tone pot is replaced with a dual-ganged pot (one wafer for each channel) and there are a few tone cap changes. I'm sure you could consult a 6G3 schematic and note the differences fairly easily. Missions's kit seems a popular mod for those who liked the idea of a 5E3 but didn't like the amp itself....it's tighter and brighter with more clean in the Volume sweep and everything is slightly less Tweed and slightly more Fender.
     
  18. kage1414

    kage1414 Member

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    check out this link. it's a diy 5E3 clone. there's links for the wiring diagram with resistor values and everything. I was told you can use 6L6's with the 5Y3 if you get the low voltage power tranny.

    http://www.triodeelectronics.com/deluxerebuild.html
     
  19. marcfrom

    marcfrom Member

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    Mission amp talking about GZ30/5V4 rectifier.

    On the Triode link it's the original 5E3 schematic.

    I will compare the 5E3 and 6G3 schematics and note the differences.
     
  20. Blue Strat

    Blue Strat Member

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    The power transformer. In other words, just don't do it.
     

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