Is 6CA7 the same as EL34?

Discussion in 'The Squawk Box' started by Phillywood, Nov 24, 2009.

  1. Phillywood

    Phillywood Senior Member

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    I have a Orange Rockerverb 100 that needs new tubes.
    It currently has EH 6CA7 tubes in it.

    I have a new set of Mullard EL34 (reissue) tubes still in the box.

    Are these the correct replacement tubes for this amp?

    The EH website says this:

    EL34 -Most common power pentode ......
    6CA7 -Big bottle beam-tetrode version of EL34

    Pentode? Tetrode? What is the difference????

    Thanks for any help....
     
  2. zeppelin101

    zeppelin101 Senior Member

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    Well pentodes have 5 metal rods and tetrodes have 12 I think? I dont know Im probably wrong Im using the latin roots.
     
  3. Torren61

    Torren61 Senior Member

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    EL34, 6CA7 and KT77 are the same tubes.
     
  4. Splattle101

    Splattle101 V.I.P. Member

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    Standard simplest valve has three electrodes: cathode, control grid and anode (or plate). Three electrodes = triode.

    The 6L6 family of valves are called 'beam tetrodes' because they have a fourth electrode between the control grid and the anode, giving them a total of four electrodes. Four = tetra, thus tetrode. The 'beam' part refers to the shaped anode plates that produce a magnetic field that forms the electron flow from cathode to anode into a beam. In some valves the beam plates are actually a separate pair of electrodes. But anyway, those beam forming plates are what make these valves 'beam tetrodes'.

    The 'KT' designation is the Marconi / Mullard name used to avoid problems with RCA, to whom they sold the American rights to the 6L6 valve in the mid 1930s. They therefore called it the 'Kinkless Tetrode', and thus the KT. The 'kink' to which the name refers is a funny notch in the frequency response of a normal tetrode valve. The beam plates overcame this problem. The 'beam tetrode' therefore = the 'kinkless tetrode'.

    The EL34 is a real McCoy, bona fide, card carrying PENTODE. The pentode, as the name suggests, has an extra grid electrode that helps smooth out the kinks of a normal tetrode. Other genuine pentode valves include the EL84 and the 6V6. I think the EF86 signal valve is a pentode, too.

    Some amps have their valve sockets wired so that pentodes and beam tetrodes can both be used. But not all. You will get bad results if you just plug an EL34 into a Fender that takes 6L6s, for example. But some are wired up to take both.
     
  5. boycey

    boycey Senior Member

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    I switched from EH6CA7s in my Matamp to JJ EL34s. There is quite a pronounced difference in tone, I found the 6CA7s a little flabby/fuzzy when pushed hard, which I didn't like. The EL34s have tightened up the bottom end, and have added a 'springiness' to the sound which wasn't there with the 6CA7s. As you can tell I'm not too good at describing amp tones but I like what the tube swap has done. If you have the Mullards there anyway then give them a go!
     
  6. Birdy

    Birdy Senior Member

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    Post of the month award on the net IMO :dude:

    Well written and great info Splattle101.


    .
     
  7. xsouldriverx

    xsouldriverx V.I.P. Member

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    yeah, why havnt you posted this before? what else do you know that youre hiding.
     
  8. Jupa

    Jupa Senior Member

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    Honestly, I wouldn't be surprised if Splattle wrote a 50 page paper on different types of tubes and how they work. Take a look at some of his older posts, always an incredible amount of good information.
     
  9. Quill

    Quill Senior Member

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    So when Phillywood - and, um, maybe any other interested parties :cool: - goes to replace his 6CA7s with EL34s, what should he expect from those Mullard Reissues? And does anybody have any interesting opinions regarding other types of EL34s? Lots of players seem to like the Winged "C". Strong recommendations, the Winged "C" comes with. How about others? Tungsol? TAD? JJ/Tesla? Sovtek? Shuguang? What sort of NOS EL34s are nice? Other alternatives besides the 6CA7 and KT77? Inquiring minds are appreciative!

    I promise, I will not, about the EL34s, ask anymore. This is the last time, about the EL34s. Not another EL34-related word. EL34s? Zipped!
     
  10. xsouldriverx

    xsouldriverx V.I.P. Member

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    many people make the EL34s, jj makes a tube with a tighter low end called the E34L. ive only seen gold lion and JJ make a kt77, which is a shame b/c its either high end lions or mid range JJ
     
  11. Quill

    Quill Senior Member

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    Interesting. btw, thanked ye over in that other thread, over there, you know, the other one about the, uh ... the tubes. You know.
     
  12. DEMENTED

    DEMENTED Senior Member

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    Ummm, no one mentioned that EL34 is European and 6CA7 is American designations, same tube otherwise. Just like EL84 and 6BQ5 are the same...right?
     
  13. Hamtone

    Hamtone Senior Member

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    As spattle mentioned its essentially the sa.e but not the same.

    The mullard reissues are fair same as jjs. For new el34s the winged c's are some of the best all around and best value. Remember some amps don't really care so much about the power tubes as they do about the pre's
     

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