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GZ34 vs 5Y3 tube

Discussion in 'Shock Brother's DIY Amps' started by Mongo Park, Apr 22, 2021.

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  1. Mongo Park

    Mongo Park Tele-Afflicted

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    I was looking at how these 2 tubes compare. I have always used a 5Y3 but I was looking at an amp that calls for a GZ34. It has 3 12ax7's and 2 6V6's. Nothing a 5Y3 can't handle.
    So what does a GZ34 provide that 5Y3 doesn't. I searched around a bit but could not decipher the explanations.
     
  2. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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  3. Mongo Park

    Mongo Park Tele-Afflicted

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    OK thanks I got it.
     
  4. archetype

    archetype Fiend of Leo's

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    What @Lowerleftcoast said. There are several rectifier tubes that will do the job, each with a different voltage drop. Dropping the voltage may result in earlier onset of sag, compression, etc. Generally it's a cheap way to experiment. Sometimes it's driven by the eye-popping cost of a real, NOS GZ34/5AR4 tube.

    I've got an old Mullard 5AR4 in my Tremolux, but bought a 5R4GB to see if the amp will sag and comrpress earlier on the dial.
     
  5. Mongo Park

    Mongo Park Tele-Afflicted

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    Well was looking and the GZ34 is not cheap so I wanted to know what I would get for my money. Also I am stuck with power transformer that runs 2A on the rectifier tube. I have not tried a 3 Amp tube to see if the transformer gets hot, rather not.
     
  6. JRapp

    JRapp Tele-Holic

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    Some amps can handle it, some can't. Wanna roll the dice on the PT? Stick to a 2 amp rectifier. The 5V4 or 5R4 are nice 2 amp middle ground rectifiers between 5AR4 and 5Y3.
     
    Last edited: Apr 22, 2021
  7. jsnwhite619

    jsnwhite619 Friend of Leo's

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    GZ34 allows for a higher value first filter cap than a 5y3. I only use JJ tubes for everything so that's all I can testify to. I know i've always seen posts about X brand 5y3 is just a relabeled 5u4 or something, but I've never dealt with that. From a 5y3, 5u4, and GZ34, I've always been able to tell a distinct difference in tone & feel of each tube, not simply "it drops/raises your voltage". Even that 5881 amp I just finished, I know you aren't "supposed" to tell any difference in rectifiers because it's single-ended, etc., etc. The difference in 5y3 and 5u4 in that was like comparing "Layla" tones to a Deluxe Reverb on 2 with my Telecaster. 5U4 was clean past 6 with my Tele; 5y3 sounded like the Black Keys on 4. Yes, voltage is different. But I've setup lower secondaries before with higher voltage tubes, and the same B+ either way sounds worlds different with a 5y3 @ 325v PT vs a GZ34 @ 275v PT, and they both come in at approximately the same voltage. No comparison in the tone & feel of each.

    To me, the 5y3 is a big part of the 6v6 Tweed sound and feel. The 5u4 & GZ34 is a key part to the Blackface sound & feel.
     
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  8. Uncle Daddy

    Uncle Daddy Tele-Afflicted

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    5r4gb, 2a filament draw and more sag than a GZ34
     
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  9. schmee

    schmee Doctor of Teleocity

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    There's a difference in tone I find also. Due to voltages and more importantly sag. If you have a low wattage amp and need it to keep up with the band, I would go with the GZ34, especially if it was designed for that. OTOH a 5Y3 may be more smooth.

    It's a wide generalism though, and details matter...
     
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  10. jsnwhite619

    jsnwhite619 Friend of Leo's

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    Reading back through everything again, I would say that if the amp is supposed to be clean at all - and probably is with a GZ34 & 2x6v6 - a 5y3 is going to be a far cry from the designed performance. The GZ34 will probably be much cleaner, tighter bass, "faster" feel & response.

    This is comparing the same amp with a 5y3 & 5u4, which are much closer in sound & feel than a 5y3 & gz34. I think this was different speakers, but same amp & guitar. You may need better speakers than a phone to hear the difference, but the 5y3 basically stays saturated sounding throughout. The 5u4 is tighter and not as dirty, in general, though both scream when the amp is cranked. But whatever the 5u4 cleans up, the GZ34 will do even more.



     
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  11. archetype

    archetype Fiend of Leo's

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    ...and NOS is relatively cheap. I just paid $20/ea for NOS GE 5R4GB.
     
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  12. archetype

    archetype Fiend of Leo's

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    The lowest price on NOS GZ34 is usually a Matsushita tube. Generally $100, but I've just seen them at VIVA Tubes for $60. IIRC they were built on Mullard equipment.
     
  13. Phrygian77

    Phrygian77 Friend of Leo's Gold Supporter

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    I don't quite understand this. What was the original issue with using a GZ34/5AR4? If it was simply price, the Sovtek GZ34 is $22. I've used tons of them and never had a single issue with any of them.
     
  14. Mongo Park

    Mongo Park Tele-Afflicted

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    The original question was what was the difference from a 5y3. Yes with some searching deals can be found.
    Some smokin food info in between here and there.
     
    Last edited: Apr 22, 2021
  15. Mongo Park

    Mongo Park Tele-Afflicted

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    Well I will have to order up a few and try them out, not that I don’t believe in the advice but sounds like another option to be able to try out.
     
  16. jsnwhite619

    jsnwhite619 Friend of Leo's

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    The bias will be way different between the two. If you want to experiment, be sure to have a pot if fixed bias or extra resistors on hand if cathode biased. Expect 40-50v B+ difference between the two.
     
  17. archetype

    archetype Fiend of Leo's

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    Results vary on current production GZ34/5AR4. Many folks find the Sovteks to be fine. Durability is another matter. The Mullard in my Tremolux has been delivering the goods for 58 years.
     
  18. Mongo Park

    Mongo Park Tele-Afflicted

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    I’ll try the Sovteks. I don’t think I will last another 58years.
     
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  19. CoolBlueGlow

    CoolBlueGlow Tele-Afflicted

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    And a less than minor detail no one mentioned as of post #18 is that the 5Y3 is a directly heated cathode, whereas the GZ34 is indirectly heated. This is a pretty major difference.
     
  20. Mongo Park

    Mongo Park Tele-Afflicted

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    As in does the indirect heated allow the tube to last longer.
     
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