1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

D&A phantom rework

Discussion in 'Home Brew' started by bearcatfan78, Jan 23, 2010.

  1. bearcatfan78

    Joined:
    Jan 23, 2010
    Messages:
    10
    Likes Received:
    0
    Thinking of converting this beast to 24LQ6's @ $12.59 each. Attached is a modified schematic showing how. Basically tying the heater of 5 tubes in series to get 24 VAC to the heaters. 120/5 = 24 Thought's???
    [​IMG]


     

  2. SmackDown

    SmackDown Active Member

    Joined:
    Apr 8, 2006
    Messages:
    448
    Likes Received:
    57
    I'm considering doing a change of glass in my Phantom. I'm thinking of going the EL519 route though. I know the pins will need re-wiring (2 of them and jumping one) and I know the pins will stretch the sockets (but I'm definitely not going back to the original tubes so the socket stretch isn't a major concern. I looked at the 24LQ6's and the 31LQ6's too. It's my project for February.


    3's
     
  3. paws264

    paws264 Active Member

    Joined:
    Apr 6, 2005
    Messages:
    647
    Likes Received:
    4

    Excellent idea, be sure to wind some bifilar type chokes (one for each bank of 5 tubes) and place them in your 120 volt series filament supply line; this will keep RF out of your AC wiring at home.

    .
     
  4. bearcatfan78

    Joined:
    Jan 23, 2010
    Messages:
    10
    Likes Received:
    0
    Well I don't know if your phantom is like mine, but pin 9 in my sockets has been removed completely. I had considered a el509/6kg6/6p45s rework until I discovered I had to change the damn sockets. Ugggggh!!! So it was back to the drawing board. That's when I decided to go with 24lq6's. Also what would you suggest the best way to make a decent bifilar type choke for this is????
     
  5. paws264

    paws264 Active Member

    Joined:
    Apr 6, 2005
    Messages:
    647
    Likes Received:
    4
    A bifilar choke is two pieces of insulated wire wrapped on a ferrite core, the purpose is to block RF from getting into your house AC lines.

    For your application, if you could fine a ferrite rod (like the kind you find in old AM broadcast radio sets) about 2 inches long and wrap the wire around it, it is not critical, just make sure that you have enough turns) that would work for you..

    A second idea is this:

    [​IMG]

    Cut a slot out of a ferrite donut and use that for your core .

    .
     
  6. bearcatfan78

    Joined:
    Jan 23, 2010
    Messages:
    10
    Likes Received:
    0
    LOL. I kinda made that sound like I didnt know how to make a bifiliar choke. No I meant what would you sugest for this application, but I got it. I like the ferite donut design alot. Thanks for the advice. :eek:) 73 :headbang
     
  7. Monk

    Monk Member

    Joined:
    May 6, 2005
    Messages:
    22
    Likes Received:
    9
    24LQ6 Phantom

    There is a much easier way to run the 24 volt tubes.
    Look at the filament supplies on the transformers...
    No choke needed.
    12 volt.
    12 plus 12 equals 24
    I've been doing these conversions on D&A's for years.



    Monk
     
  8. paws264

    paws264 Active Member

    Joined:
    Apr 6, 2005
    Messages:
    647
    Likes Received:
    4
    Adding the voltage of the 12 volt windings in phase?

    .
     
  9. liquidh8

    liquidh8 Active Member

    Joined:
    Aug 7, 2011
    Messages:
    273
    Likes Received:
    7
    Old thread I know, but did anyone actually convert to the el-509/6p45s tubes? I have a 10 tube phantom that may need tubes, and these are cheaper to use, even with buying new sockets.
     
  10. BJ radionut

    BJ radionut Supporting Member and 6m addict

    Joined:
    May 9, 2008
    Messages:
    3,491
    Likes Received:
    3,684
    gla1000eng

    This link should be of help...I have done a couple of MAV 250's...gutting the 4 tube driver stage...pairing up the 2 xformers on the final stage, bigger current diodes and extra filter caps...worked well.
    The GLA-1000 to 519's a little tricky as the tubes are slightly taller... on the D&A's...when you rework the sockets just drop them down about an inch, open the socket holes a little so the tube fits through and gets air. I also added a small fan to move air under the chassis to keep the sockets and PS caps/diodes from getting warm...Worked well...
    Next one that comes my way cheap will get a pair of GI7BT's...:D
    http://www.ne.jp/asahi/evo/amp/device/el509.pdf I have used the 509's very similar mostly...both OK...509's fairly plentiful still about 20USD each +/_...last 4 I bought were 18USD...really a heavy glass version from Russia...Winged "C" brand (old Svetlana factory) http://ko4nr.tripod.com/upgrades_and_modifications_for_d.htm
    Be Careful
    GL
    All the Best
    BJ
     
    #10 BJ radionut, Sep 16, 2011
    Last edited: Sep 16, 2011
  11. ElectronTubesRule

    ElectronTubesRule Active Member

    Joined:
    Sep 6, 2011
    Messages:
    257
    Likes Received:
    15
    Well I am at a Bistro on campus so keep that in mind. Waiting on my better half. I did not see any resistors in the tube 120 feed line. Your first tube will pop more then likely then it will pop the next and the next in series etc......You need to stick a resistor and a diode in that line. If the ac is dirty then you will need a cap in their too to clean that ac up a bit. Also what is your local power like? Is it clean or full of ripples. If your power fluctuates much you will have issues.

    Just my $.02 though.

    You can actualy use doubler,tripplers and voltage divider's to power tube amp with no transformer at all. Some guys in Europe on 220/240 do this. It would not be my first choice but if a budget does not allow it is better then nothing.
     
  12. liquidh8

    liquidh8 Active Member

    Joined:
    Aug 7, 2011
    Messages:
    273
    Likes Received:
    7
    I have to check the x-formers, since there are 3, and see if they are all good. I think they are supposed to be 800vdc at the sockets, but with all 11 tubes out (the little keying tube to) Will I read that 800vdc? I may have to just salvage different parts and make a different amp.
     
  13. BJ radionut

    BJ radionut Supporting Member and 6m addict

    Joined:
    May 9, 2008
    Messages:
    3,491
    Likes Received:
    3,684
    The el-509's are basically a drop in replacement for the 6lq6/6me6 or the 6mj6's all are 6.3v filament tubes...
    You have to change the socket configuration wiring as the grid and heater pins do differ from the 6lq6 vs the el-509's. The existing sockets are the same pin count and el's will fit. I however preferred to change them as the ceramic replacements I found were a much stouter version than the Bakelite versions D&A used in most of their amps...

    Now a little logic...11 tube sockets at $2.50 each +/- = say $28.00
    11/ el-509's at best price $15.00 each (more like $20-$22 with shipping)....
    11 x $20.00 = $220.00 + sockets $28.00 = $248.00 parts only
    Add in 20 or more hours labor gutting the existing RF deck / installing new sockets and wiring...how much is your time worth?

    Now you understand why you can buy or carry those "Things" away for a song!
    The 4 tuber's like the Mav 250's much less of and investment and yield an amp project for less than parts cost of one of those monster autrosities...IMHO

    Will you learn something....most certainly!....but the output difference maybe 1 S unit(6db)...IMHO...no not really....but your call to make
    Even if you could find 6lq6's in a lot for $25 each....$300 just to re-tube her as she sits.

    Now your question...yes you can read the B+ voltage with the tubes removed...but watch your butt...only with a GOOD meter and test leads rated at a 1000 volts or more...Be careful the power in that amp will kill you in an instant....if it does not...you may wish you did not wake up!
    Please be careful
    Adding tubes together like 5/24v to equal 120v filament, again IMHO is a death wish or a good reason to have the FDNY on stand-by when you throw the switch...I won't even touch a Firebird or the likes that does not contain a separate filament winding rated for the tubes (6.3/12v OK) and weird combinations like the old TV's used...nope not anymore!
    There is many a story there by anyone who worked on those...(y)
    GL...Be careful
    All the Best
    BJ
     
  14. liquidh8

    liquidh8 Active Member

    Joined:
    Aug 7, 2011
    Messages:
    273
    Likes Received:
    7
    I think you are right, I got the amp not working for almost nothing. If the xformers work, or 1 or 2, I could use the case, tank circuit, switches and other misc parts for a different build. I really just have to find something I can copy.

    My labor is of no concern, I have been an A-10 Warthog electrician/avionics craftsman/supervisor for 13 years, I have the ability to build it. But the tube knowledge is a bit lacking I forgot pretty much everything from college about tube amps, lol. But the price of parts is definitely an concern.
     
  15. BJ radionut

    BJ radionut Supporting Member and 6m addict

    Joined:
    May 9, 2008
    Messages:
    3,491
    Likes Received:
    3,684
    Google GI7B...Lots of info...simple and can be very clean if done correctly
    GL
    All the Best
    BJ(y)
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!