Results 1 to 11 of 11

Thread: Tube swap for another ones.

  1. #1
    Tone Member
    Join Date
    Sep 2011
    Location
    In france , near the german frontier.
    Posts
    187

    Default Tube swap for another ones.

    Hello people.

    I have a question about tube swap in an power amp.
    At this moment I have 8 EL34 tubes in my marshall amp.
    It's time to change them because of their oldness.
    But if I change I would like to get some sound equivalent tubes without changing the Charakter too much.

    The tubes on my amp are the originals and I've never change them. Don't ask me wich are in there.. I really don't know.

    For what I read some manufacturers are making tubes with another sound Charakter.
    Electro harmonics, groove tube, ruby tubes, JJ etc....
    What I would like are EL34 with little more bass and a little less brittle highs/presence. A little less AC/
    DC Charakter in short lol.

    I' don't like 6L6 tubes.... There are to dirty in my opinion. And I don't like the mids tonality of them. But there modern sounding, especially for metal.

    I read a lot about KT66 kt77 or 5881 for replacement.

  2. #2
    LoveMachineologist jeremy's Avatar
    Join Date
    Mar 2004
    Location
    albany, ny
    Age
    42
    Posts
    29,806

    Default Re: Tube swap for another ones.

    6l6gc are too dirty? they are usually THE go too clean amp big bottle tube. kt77 are sorta between a el34 and 6l6gc and might be right along the line of what you want. a 5881 is a rugged 6l6 (not 6l6gc) and typically has less bottom and a little more breakup compared to a 6l6gc. i love kt66 tubes (at least old ones) but they pull a fair amount of heater current, they have the same pin out as a 6l6. big strong bottom and clear but not shrill top end. new production ones tend not to be actual kt66 from what ive seen but there are some out there, i havent kept up with what is and what isnt

  3. #3
    Tone Member
    Join Date
    Sep 2011
    Location
    In france , near the german frontier.
    Posts
    187

    Default Re: Tube swap for another ones.

    OK thanks for the answer.
    Yes... Dirty... I mean dirty mids with saturation.
    But perhaps my feeling is bad because I judge the 6l6 in metal amps like angl or Peavy.


    It exist a lot of tubes.
    I look for less bright ones. Less shrill or better say, less crisp.
    Perhaps kt 77 or jj El 34 II

  4. #4
    Mojo's Minions Gtrjunior's Avatar
    Join Date
    Jun 2017
    Location
    Wherever you go, there you are.
    Posts
    6,005

    Default Re: Tube swap for another ones.

    Its hard to recommend a set of tubes when we dont know what you have in the amp now.
    More bass and less brittle highs as compared to what?
    What amp is it that has 8 power tubes?

  5. #5
    Tone Member
    Join Date
    Sep 2011
    Location
    In france , near the german frontier.
    Posts
    187

    Default Re: Tube swap for another ones.

    Quote Originally Posted by Gtrjunior View Post
    It’s hard to recommend a set of tubes when we don’t know what you have in the amp now.
    More bass and less brittle highs as compared to what?
    What amp is it that has 8 power tubes?
    An marshal' El 34 100/100 dual monobloc power amp

  6. #6
    Mojo's Minions
    Join Date
    Nov 2018
    Location
    In a Studio with your Mom
    Posts
    4,216

    Default Re: Tube swap for another ones.

    Quote Originally Posted by Micha View Post
    An marshal' El 34 100/100 dual monobloc power amp
    Wow, what are you pushing with that mother?
    For me, when everything goes wrong thats when adventure starts. Yvonne Chouinard

  7. #7
    Tone Member
    Join Date
    Sep 2011
    Location
    In france , near the german frontier.
    Posts
    187

    Default Re: Tube swap for another ones.

    Quote Originally Posted by NegativeEase View Post
    Wow, what are you pushing with that mother?
    Lol

  8. #8
    Mojo's Minions Lake Placid Blues's Avatar
    Join Date
    Nov 2005
    Posts
    3,639

    Default Re: Tube swap for another ones.

    I' don't like 6L6 tubes....
    I read a lot about KT66 kt77 or 5881 for replacement.
    A 5881 sounds pretty much the same as 6L6GC. The difference is that the 5881 will get dirtier slightly sooner. A true 5881 will not last long in a high voltage amp.

    A KT66 is of the same family as the 6L6 but has a warmer overall sound with less scooped mids. It handles 500+ volts. 6L6 family tubes have glassy, crisp, highs compared to EL34 types to my ears.

    See below for comments on the KT77.

    I look for less bright ones. Less shrill or better say, less crisp.
    Perhaps kt 77 or jj El 34 II

    What I would like are EL34 with little more bass and a little less brittle highs/presence.
    The KT77 is an EL34 electrically that sounds more like a 6L6GC. They are noted for bright clear highs. A better EL34 alternative for what you describe is the 6CA7. It has a strong bass like a 6L6 but is less bright than a KT77.

    Currently there are two 6CA7s available:

    EH6CA7
    JJ 6CA7

    A 6CA7 is a beam tetrode like a 6L6 as is any KT tube. These have more open mids than a pentode. EL34s are pentodes which tend to have thicker mids. Among EL34s with stronger bass:


    Chinese EL34B (Tube Amp Doctor, Ruby). This one is interesting because it is actually a beam tetrode but sounds like a traditional EL34.
    Russian EL34B (Tung Sol brand). A true pentode. This one has more bass because the impedance is altered slightly. This might be what your looking for. But a touch of 6L6/5881 glassiness.
    Russian EL34 (Mullard banded). Warmer, less brittle, highs, and warm mids. Will give you the warmer tones you seek but not much stronger bass.
    JJ E34L. A pentode but is 30 watts plate dissipation and usually has stronger bass.

    One problem with your stated needs. Stronger bass usually comes with stronger highs as a package deal.

  9. #9
    Mojo's Minions Lake Placid Blues's Avatar
    Join Date
    Nov 2005
    Posts
    3,639

    Default Re: Tube swap for another ones.

    In most cases switching over to a KT66, 6L6, 6550, or KT88, from EL34s in a fixed bias (adjustable bias) amp will require modifications to the amp to bring the bias supply within range.

    I mention the KT88 because it should have all the things you list: More bass, cleaner, and warmer highs, but be aware that you probably won't be able to just plug these in and go with a simple re-bias.

    On edit: The 6CA7 are designed to substitute for EL34s. They usually require no circuit modifications in an EL34 amp and they are softer sounding than a 6550.
    Last edited by Lake Placid Blues; 11-09-2019 at 08:52 AM.

  10. #10
    Tone Member
    Join Date
    Sep 2011
    Location
    In france , near the german frontier.
    Posts
    187

    Default Re: Tube swap for another ones.

    Thanks you very vuch. I didn't expect so much information.

  11. #11
    Ultimate Tone Slacker
    Join Date
    Jul 2011
    Location
    Pennsyltucky
    Posts
    1,917

    Default Re: Tube swap for another ones.

    Quote Originally Posted by Lake Placid Blues View Post
    A 5881 sounds pretty much the same as 6L6GC. The difference is that the 5881 will get dirtier slightly sooner. A true 5881 will not last long in a high voltage amp.

    A KT66 is of the same family as the 6L6 but has a warmer overall sound with less scooped mids. It handles 500+ volts. 6L6 family tubes have glassy, crisp, highs compared to EL34 types to my ears.

    See below for comments on the KT77.



    The KT77 is an EL34 electrically that sounds more like a 6L6GC. They are noted for bright clear highs. A better EL34 alternative for what you describe is the 6CA7. It has a strong bass like a 6L6 but is less bright than a KT77.

    Currently there are two 6CA7s available:

    EH6CA7
    JJ 6CA7

    A 6CA7 is a beam tetrode like a 6L6 as is any KT tube. These have more open mids than a pentode. EL34s are pentodes which tend to have thicker mids. Among EL34s with stronger bass:


    Chinese EL34B (Tube Amp Doctor, Ruby). This one is interesting because it is actually a beam tetrode but sounds like a traditional EL34.
    Russian EL34B (Tung Sol brand). A true pentode. This one has more bass because the impedance is altered slightly. This might be what your looking for. But a touch of 6L6/5881 glassiness.
    Russian EL34 (Mullard banded). Warmer, less brittle, highs, and warm mids. Will give you the warmer tones you seek but not much stronger bass.
    JJ E34L. A pentode but is 30 watts plate dissipation and usually has stronger bass.

    One problem with your stated needs. Stronger bass usually comes with stronger highs as a package deal.
    I have been really happy with the E34Ls in my Road King, they sound so much better than the stock EL34s

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •