Mark IV owners - Experience with different tubes?

Discussion in 'Amps and Cabs' started by leper messiah, Feb 12, 2006.


  1. leper messiah

    leper messiah Member

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    Have any of you TGP members who own the Mark IV experimented with different tube combinations? I own a Mark IV and a Rectoverb, and when I switch out the 6L6's in the Recto for El34's I don't notice much of a difference in the gain channel, but the the clean channel definitely loses something, so I stick with the 6L6's.

    I'd be interested in hearing from anybody who has tried EL34's or other tubes in the Mark IV (I haven't had a chance to try any yet because I gave my EL34's to a friend).
     
  2. Badger71

    Badger71 Member

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    There is a noticeable difference to me when I have some Svetlana =C= EL34s in the slots. There is a definite boost in the upper mids. It breaks up way sooner in a raunchier way. The clean channel brightens up, and R2 sweetens up to a nice "British" tone. The lead channel seems to be a little too mid-heavy with them in, though. Definitely requires some EQing to balance things out nicely. This is on the Tweed, Class A setting. Blended with the 6L6s in Simul-Class, this mid boost isn't as prominent, but it's definitely there. The EL34s will help if you have weak and dark humbuckers in your guitar. If your guitar is brighter and middy, I'd stick with good 6l6s.
     
  3. leper messiah

    leper messiah Member

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    Thanks, Badger. I'm going to pop some EL34's in as soon as I get a chance...I'd like to hear that raunchier breakup that you described. I'm not dissatisfied with the stock 6L6 Mark IV sound...I just like tinkering around the options.
     
  4. Stormin

    Stormin Supporting Member

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    When I had my Mark IV, I didn't find that the EL-34's gave me a raunchier breakup at all. The best way I can describe it is that using the EL-34's changes the frequencies where the overdrive happens - more upper mids, less highs etc. I thought it also helped out in the low end department as well. Not more bottom, just a smoother bottom

    When I was doing this, I used SimulClass and Pentode. The Mark IV definately had a better more in-your-face punch in this config than just doing 6L6's.

    If I had another Mark IV, I'd definately run it this way again.

    YMMV,

    Stormin!
     
  5. Badger71

    Badger71 Member

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    I'm running Svet =C= 6L6s currently in all four slots. Those tubes really sound great over the stock Boogie tubes. I have a new RI Tung-Sol 12ax7 in V1 with EHs and Shuguangs in the rest. They really bring out some good tone from the amp. Don't be afraid to run an OD or boost to liven up the amp. Yeah, I know, amp OD is better. But if guys like Van Halen, SRV, Randy Rhoads, etc....can use something other than amp OD, so can we! I use a Maxon OD-9 at times. A good treble booster, like a Beano, that allows full frequency boost can really make the amp shine also. YMMV.
     
  6. LavaMan

    LavaMan Gold Supporting Member

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    I have owned two Mark IV's and my favorite combination is 6L6/EL-34. You do loose a little on the clean channel, but I love what the EL-34's do to both gain channels. I have JJ's in my Mark IV now in this confirguration and I love it.
     
  7. scottywompas

    scottywompas Member

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    I just popped two el34's in the outside sockets of my MKIV and what a difference. I loved the sound with all 6l6's but I have previously owned several EL34 amps and for the high gain stuff that's where it's at for me. I do a lot of metal with the amp and use the classic mid scoop on the EQ . The clean is a little weaker and as of yet I have not really found anything in the R2 channel to write home about.

    Scott

    :dude
     
  8. Troubleman

    Troubleman Silver Supporting Member

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    I own a MkIV combo. I think the Fenderish glassy-clean takes a bit of a hit with EL34's but the overdrive lows seem to smooth out and mids seem to shift a bit in frequency. Decent tones with either tube. When I really used that amp (two herniated disks preclude its usage; i'm up for trades really), I was dialing in more clean to medium gain tones, so 6L6's worked better. Never tried blending the two.

    jb
     
  9. leper messiah

    leper messiah Member

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    Thanks all for chiming in here. Scott, what type of tubes did you plug in? Did you also change the V1 preamp?
     
  10. wire 247

    wire 247 Member

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    I use the 6l6/el34 combo and like it much better. the 6l6s are svetlanas and the 34s are jjs, the jjs are a little cleaner so I did not notice any earlier breakup, I love the overall sound......
     
  11. leper messiah

    leper messiah Member

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    Well, I jammed a couple of EL34L JJ's into my Mark IV and the difference is obvious. It adds some upper mid pizzaz to the sound. I'd say it adds a touch of Marshall character. After redialing in my sound, I really must admit that I have achieved a better lead tone, and a better rhythm sound as well. Replacing the end 6L6's with EL34's has added some tonal qualities that my sound was missing, and subtracted some qualities that I didn't like. The downside--which I expected--is that the clean channel suffers a little, but overall I like the amp better with the EL34's in. Don't spend a whole lot of time on the clean, although I do use it. I've also started to play around with the V1 slot. I tried a JJ ECC803S which sounded worse than the stock Boogie. I also have some Sovtek tubes kicking around that I want to try.
     
  12. scottywompas

    scottywompas Member

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    I just jammed som GT EL34's in there. I havn't messed around witht the preamp tubes at all. I really only did this to begin with because one of the 6l6's was dying on me and I had the EL34's here from a previous amp. Overall I love this set up and will keep it this way.

    Scott
    :AOK
     

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