Results 1 to 13 of 13

Thread: 6l6 to el34 tube swap?

  1. #1
    Member
    Join Date
    Jul 2009
    Posts
    33
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    0

    6l6 to el34 tube swap?

    I'm sure many will think this is a question that we all should know the answer to so I may be the only one. I have a MMRD50 with 6l6's and wondered if el34's could be substituted for them with out significant changes? Thanks in advance for your patience!

    0 Not allowed! Not allowed!

  2. #2
    Supporting Member Jazz P Bass's Avatar
    Join Date
    Dec 2008
    Location
    Wernersville, PA
    Posts
    12,940
    Thumbs Up/Down
    Received: 533/3
    Given: 288/0
    Rep Power
    26
    #1 on the list is the power transformer.
    -Can it supply the additional heater current that the EL34's require.

    It goes without saying that the bias voltage will have to be lowered to accommodate the EL34's.

    0 Not allowed! Not allowed!

  3. #3
    Senior Member
    Join Date
    Jul 2011
    Location
    Adelaide, South Oz
    Posts
    750
    Thumbs Up/Down
    Received: 85/0
    Given: 4/0
    Rep Power
    9
    Plus
    Check that there is a link between pins 1 and 8 on ALL of the output tube sockets. This to connect the EL34 suppressor grid to the cathode. 6L6 doesn't have a suppressor grid so doesn't need that connection. A lot of amps will have that link in them just so that EL34 or 6L6 can be used. If your amp does not have that link then you will need to add it.

    Cheers,
    Ian

    0 Not allowed! Not allowed!

  4. #4
    Supporting Member
    Join Date
    Dec 2009
    Location
    UK
    Posts
    3,468
    Thumbs Up/Down
    Received: 198/0
    Given: 24/0
    Rep Power
    14
    Check if pin 1 is used as a tie point for another component such as the grid stopper or screen resistor. If so you will need to move that component end off pin 1 and connect pins 1 to 8 as Ian suggests.

    I also like to increase the screen resistors from 470R to 1K for EL34.

    0 Not allowed! Not allowed!

  5. #5
    Senior Member
    Join Date
    Jul 2011
    Location
    Adelaide, South Oz
    Posts
    750
    Thumbs Up/Down
    Received: 85/0
    Given: 4/0
    Rep Power
    9
    What Mick says too - important. Even if you leave 6L6 in, changing the screen resistor to 1K 5 Watt Rat Coffin types will extend the life or your tubes.
    Cheers,
    Ian

    0 Not allowed! Not allowed!

  6. #6
    Member
    Join Date
    Jul 2009
    Posts
    33
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Rep Power
    0
    Ok! Thanks all of you for the great information. Since the MM is stock as I bought it in 82 I think a good work around would be just find a nice 40 or 50 watt el34 that was designed that way.
    BTW Gingertube, what is "Rat Coffin" type and do they reduce current/voltage?

    0 Not allowed! Not allowed!

  7. #7
    Senior Member
    Join Date
    Jul 2011
    Location
    Adelaide, South Oz
    Posts
    750
    Thumbs Up/Down
    Received: 85/0
    Given: 4/0
    Rep Power
    9
    "Rats Coffin" type is slang for the white ceramic block style power resistor.
    Like this one:
    https://www.digikey.com.au/product-d...0KW-5-ND/18703
    They introduce some screen compression and limit screen power dissipation.
    Cheers,
    Ian

    0 Not allowed! Not allowed!

  8. #8
    Senior Member
    Join Date
    Jan 2014
    Location
    Chiraq
    Posts
    1,002
    Thumbs Up/Down
    Received: 213/5
    Given: 249/1
    Rep Power
    7
    oh like, that's what you get for squeelin. Mousetrap for a rat

    not like an animal rat that nibbles your cookies while you're out.

    just some old fashioned mob justice i see

    0 Not allowed! Not allowed!

  9. #9
    Old Timer Leo_Gnardo's Avatar
    Join Date
    Sep 2012
    Location
    Dogpatch-on-Hudson
    Posts
    6,399
    Thumbs Up/Down
    Received: 1,417/21
    Given: 1,207/0
    Rep Power
    14
    I've seen those called "ant coffin."

    0 Not allowed! Not allowed!

  10. #10
    Supporting Member
    Join Date
    Dec 2009
    Location
    UK
    Posts
    3,468
    Thumbs Up/Down
    Received: 198/0
    Given: 24/0
    Rep Power
    14
    And 'Sugar cubes'

    0 Not allowed! Not allowed!

  11. #11
    Don't forget the joker g1's Avatar
    Join Date
    Feb 2010
    Location
    Canada, somewhere north of Fargo
    Posts
    11,831
    Thumbs Up/Down
    Received: 1,667/23
    Given: 4,281/11
    Rep Power
    22
    and 'sand box'

    0 Not allowed! Not allowed!
    Just because they don't have tubes doesn't mean they don't have feelings! - glebert

  12. #12
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    32,142
    Thumbs Up/Down
    Received: 1,882/7
    Given: 0/0
    Rep Power
    55
    Wow, you know, all these names are colorful and fun. In all my years, I never adopted a name for them, I still call them rectangular ceramic resistors. Kinda trips off the tongue, donit?

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  13. #13
    Old Timer Leo_Gnardo's Avatar
    Join Date
    Sep 2012
    Location
    Dogpatch-on-Hudson
    Posts
    6,399
    Thumbs Up/Down
    Received: 1,417/21
    Given: 1,207/0
    Rep Power
    14
    Quote Originally Posted by Enzo View Post
    Wow, you know, all these names are colorful and fun. In all my years, I never adopted a name for them, I still call them rectangular ceramic resistors. Kinda trips off the tongue, donit?
    Better than the brand names I see on 'em: Xicon, Yageo. "Workman" on the old ones. I picture a sweaty guy with pick n shovel, what's he need a square cement resistor for? Hm, maybe he's the one mixing the mortar for a new batch.

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. EL34 vs 6L6 tube comparison in Laney IRT120
    By Claudio Passamani in forum Other Amps
    Replies: 5
    Last Post: 04-15-2014, 03:32 AM
  2. EL34 to 6L6 change
    By mikeboone in forum Theory & Design
    Replies: 9
    Last Post: 08-17-2012, 04:10 PM
  3. Use a 6L6 or EL34 in place of the 6V6
    By brodude in forum Theory & Design
    Replies: 29
    Last Post: 01-30-2010, 07:09 AM
  4. 6l6 to el34 convertion
    By bennieusmaximus in forum Guitar Amps
    Replies: 0
    Last Post: 01-22-2009, 12:54 AM
  5. El34, 6l6, 6v6
    By russ_guitarboy in forum Tubes (Valves)
    Replies: 6
    Last Post: 05-23-2007, 09:12 PM

Bookmarks

Posting Permissions

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