The DIY Tube Head Thread

Discussion in 'Amps and Cabs [BG]' started by IronRadio, Aug 29, 2008.

  1. IronRadio


    Jan 8, 2008
    I have always wanted to build a tube head of my own design totally from scratch. Well recently I got my opportunity and built the one, the only model DB1, 225W all tube head. And here it is:



    I designed the preamp to use a 6SL7, the phase transformer driver is a 6L6 and it uses 4 - KT88s in dual push pull. Some astute observers may ask about the phase and output transformers and say "Aren't those off a Fender 300PS?" I would reply no, because they're NOS!

    And that's where the similarities end.

    I then had to get a nice cab for it so I had one custom built. Here it is!


    It turned out quite well and is a definite keeper.

    Perhaps other folks have similar stories?
  2. Bulltrout

    Bulltrout Gold Supporting Member

    Jun 13, 2007
    Edmonton, Alberta
    I would love to hear some sound clips of this bad boy.
  3. IronRadio


    Jan 8, 2008
    It does the B string REALLY well. I can literally rattle the dishes in the kitchen...
  4. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Geez, no wonder you want to sell your B-15! Looks great, dude. Nice touch to use a 6SL7. Wish I could do stuff like that. I'd have long ago electrocuted myself ;)
  5. IronRadio


    Jan 8, 2008
    Thanks, Jimmy! Yea, I wasn't getting enough gain out of the 6SN7 so I dropped a 6SL7 in there. Much better. But I'd still like to have it be able to lay waste to large tracts of land better than it does now, so I think I'll dial up the 6L6 plate voltage a bit. Then I'll have to get a destructive devices license for it and my 1x18 EV cab... :hyper:
  6. bobyoung53

    bobyoung53 Supporting Member

    Nice job!!!!, what's next 400 watts? Really beautiful job. I've often wanted to make an amp out of the back of the old RCA tube manuals but it would never end up looking anyway near as nice as yours and wouldn't be my own design of course.
    This is probably a stupid question, but what is that big round thing on top of the chassis on the far right? It looks like a giant toroidal transformer like they used in the SVT preamp for the mid range control.
  7. IronRadio


    Jan 8, 2008
    That is the power transformer....
  8. like the tx coupled pi a nice '40s hifi touch.
    Where did you get the toroidal power tx? and what output tx did you use?

    I'm thinking of doing one with 2 6SL7s that I can switch to add 2 more gain stages for overdrive and using a pair of 4CX250Bs or the newer 4CX350Bs.

    sort of a B-15 gone very bad.

  9. ... and far right is the output transformer?
    Looks like you've got another couple in there as well.
  10. IronRadio


    Jan 8, 2008
    No no.....

    First photo, left to right -

    Output Transformer
    Phase Splitter Transformer
    Power Transformer

    And the balance worked out perfectly.

    Weight - 60#
  11. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Nice job, very clean. And we don't need no stinkin' tone controls :D
  12. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Hey, that's right...there's no tone controls. Pure genius! Who needs 'em? Flat is where it's at! That is, if it's flat. I don't see any reason why it wouldn't be, though.
  13. IronRadio


    Jan 8, 2008
    Power Transformer
    Antek 4T360 - ebay
    Might have gone with the 4T400 or 4T450 ...

    Output and Phase Splitter Transformers
    NOS Fender 300PS - ebay

    Transmitter tubes?
    But very cool.
  14. IronRadio


    Jan 8, 2008
    Yup, no damn tone controls, it's flat and hi-fi.
    The bass is the place for the tone controls...
  15. toobalicious


    May 6, 2008
    triad, nc
    indeed... i was wondering about that. no shaping at all? i even "need" the ones on my bassman 100, even as uselessly ineffective as they are.


    it looks just great, man. i love the marshallaneyhiwatt-esqe cab, too, what with the piping and the plaque.... pretty much my favorite cosmetics for an amp head--- and i am mostly a fender guy!
  16. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    Where's the rectifier? I assume you're using diodes but I don't see 'em.

    Or is there a 5u4 or 5y3 hidden behind one of the KT88s?
  17. amper


    Dec 4, 2002
    Neither of those tubes would in any way be capable of supporting a quartet of KT88's, even multiples of them in parallel.
  18. amper


    Dec 4, 2002
    I don't suppose you'd be willing to share the schematic, would you?
  19. I do not normally see those Toroidal PT in a tube head. I see them in SS Power Amps all the time. But then again I am more accustomed to looking at guitar amps. What is the advantage to those type of PT?
  20. rcubed


    May 8, 2008
    San Diego, CA
    I'd like to build one of those Weber kits eventually.