Post-ClassicTone OT suggestion?

Discussion in 'Amp Tech Center' started by jsnwhite619, Nov 9, 2020.

  1. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    So, as luck would have it, I came up with a nice hot rodded Tweed Princeton design this year with a 5881 tube and used the 15W ClassicTone OT for it. Tube Depot is out of stock already for them. Does anyone have a suggestion for a different approx. 15W SE OT to use in the future?
     
  2. ThermionicScott

    ThermionicScott Poster Extraordinaire

    Age:
    41
    Posts:
    6,483
    Joined:
    Dec 3, 2005
    Location:
    CID
    Hammond has a good line of single-ended iron. Maybe overkill for a guitar amp, but definitely enough: http://www.hammondmfg.com/125SE.htm (there's a link to their hi-fi offerings from that page)

    What operating points do you have in mind? :)
     
    King Fan and jsnwhite619 like this.
  3. Nickfl

    Nickfl Friend of Leo's

    Posts:
    2,661
    Joined:
    May 24, 2016
    Location:
    Florida
    Weber sells a 15W, 5K transformer: https://tedweber.com/wse15/ I haven't used that one but I've been happy with their transformers in the past.

    If you want USA made, Edcor would be my first choice. Their prices are great and they have just about any option you could want for OT specs as long as you can wait 6-8 weeks or more...
     
  4. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    If I remember correctly, I was in the 350v B+ range with a 5u4 & 5881, and I used the 5k primary, 8R speaker. It was a bada$$ amp - I built a 5e3 sized cabinet and stuck a C-Rex in it. But a local guy played it and just made too good of an offer on it. "No worries, I'll just build myself another one later." That's my luck...the transformer company closes shop.

    So is Weber foreign made?
     
  5. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    I knew there was a popular Hammond, but couldn't remember which one. I use Hammond for everything I can, but the 15W OT from ClassicTone was the only one I knew of for that setup. A quick search found me enough reviews and discussion about it that I think I'm already settled on it for when the time comes. It is a little more expensive, but if I can get the PT & OT from the same source, I'll probably save the difference on shipping or at least break even.

    It looks to be popular for the Epiphone Valve Jr amps. I like Hammond and it will handle what I need. So, not trying to cut things off, but out of the available choices, I think I've found the winner.
     
    ThermionicScott likes this.
  6. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    For reference, here is the amp.

    Clean


    Cranked
     
    jman72 and ThermionicScott like this.
  7. tubedood

    tubedood Tele-Holic

    Age:
    56
    Posts:
    562
    Joined:
    Sep 25, 2018
    Location:
    Orlando
    On my SE hot rod Princeton Tweed I used the Allen TO11S, it's 8k for a 6V6 or 4k for bigger bottles. I like Weber so far for their power transformers, haven't tried their output transformers.
     
  8. Nickfl

    Nickfl Friend of Leo's

    Posts:
    2,661
    Joined:
    May 24, 2016
    Location:
    Florida
    Yeah, I believe they have them made in China or elsewhere in the far east. I've used their output transformers in a couple of builds (may have used a PT once too but I'm not sure) and they seemed comparable quality to classic tone to me. I've used their 7k primary SE OT and it sounded great in an octal preamp tweed princeton circuit.

    Edcor is a step up in build quality IMO, I don't know if that translates to sounding better, but they do look nice for what that's worth.
     
    zook and jsnwhite619 like this.
  9. ThermionicScott

    ThermionicScott Poster Extraordinaire

    Age:
    41
    Posts:
    6,483
    Joined:
    Dec 3, 2005
    Location:
    CID
    Nice references!

    I've got an unused JJ KT88 in the stash. Every so often I think about turning it into a big single-ended amp, but I need another amp like a hole in the head... :lol:
     
  10. Timmay

    Timmay Tele-Meister

    Age:
    52
    Posts:
    198
    Joined:
    Apr 22, 2020
    Location:
    Nutbush City
    I'm in the process of building a 5f2a running a GZ34 and a KT88. Been slow going. Working 60hr weeks and it's bow season so......

    Anyway, I have a 15 watts Classic Tone OT for it, but I'm thinking of going with this 25 watt weber instead. What say y'all? Thinking this might be one for you to consider as well Jason?
    https://tedweber.com/wse25/

    Board is populated and Pt mounted. I'll start a thread on it once I get the hookup wires on and am ready to start soldering. Would like some of y'all who actually know what your doing to look it over before I get ahead of myself.
     
    Last edited: Nov 10, 2020
  11. zook

    zook Friend of Leo's

    Posts:
    2,855
    Joined:
    Aug 6, 2003
    Location:
    Cochise, AZ
    I have many holes in my head :)
     
    ThermionicScott likes this.
  12. King Fan

    King Fan Poster Extraordinaire Ad Free Member

    Posts:
    7,176
    Joined:
    Jan 1, 2013
    Location:
    Salt Lake City
    FWIW, Amp Parts Direct is getting Heyboer to dupe the more popular CT transformers. Is this '8031' model equivalent to your original CT?

    F246AE9A-F6B9-462E-8B3F-F7C1755FAF1D.jpeg
     
  13. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    Definitely looks to be it in the notes.
     
  14. ThermionicScott

    ThermionicScott Poster Extraordinaire

    Age:
    41
    Posts:
    6,483
    Joined:
    Dec 3, 2005
    Location:
    CID
    I'd go big! The theoretical max output of a signal-ended amp is half of the idle dissipation. So if you're running the KT88 at its 42 watt max into the perfect load impedance, you'd get about 21 watts before transformer and speaker losses. Even if your amp "only" ends up making ~15 watts, the bigger iron will help with low end.
     
    Timmay likes this.
  15. schmee

    schmee Doctor of Teleocity Silver Supporter

    Posts:
    17,305
    Joined:
    Jun 2, 2003
    Location:
    northwest
    I just buy the best price in a good brand like Hammond etc. EXCEPT New Sensor. (are they still in business?)
     
  16. dan40

    dan40 Friend of Leo's

    Posts:
    2,367
    Joined:
    Aug 19, 2015
    Location:
    Richmond Va
  17. Achysklic

    Achysklic Tele-Afflicted

    Posts:
    1,156
    Joined:
    Feb 7, 2013
    Location:
    Ohio
    I bought an extra classic tone OT for my 5e3 and never used it. I would sell it.
     
  18. James Knox

    James Knox Tele-Afflicted

    Posts:
    1,102
    Joined:
    Aug 13, 2003
    Location:
    Phoenix
    Would one of these work?

    Hammond 1750B... 10 Watts, Primary 5482 ohms, Secondary 8 ohms, 70 Hz to 10kHz, 17.88 mA max.
     

    Attached Files:

  19. James Knox

    James Knox Tele-Afflicted

    Posts:
    1,102
    Joined:
    Aug 13, 2003
    Location:
    Phoenix
    @jsnwhite619 What have you discovered so far? I just finished a couple Champs, one with the Hammond 1750B $33 and one with the Allen Amplification TO11S $49. I am comparing to the 5F2A 5881 Build that you inspired. Mine has the same ClassicTone trannys you used. TheY all sound really good. Haven’t picked a favorite yet. Need more playing time, lol.

    BTW, sorry you let your 5F2A 5881 go... it is currently my Favorite, my Keeper!
     
  20. jsnwhite619

    jsnwhite619 Friend of Leo's

    Age:
    37
    Posts:
    3,805
    Joined:
    Sep 10, 2013
    Location:
    Georgia
    I haven't done much looking really beyond the Hammond 125ESE. That 15W OT was the only thing I still used from Classictone, so their shutting down doesn't affect me other than that. Next one I build will probably use the 125ESE and see how I like it.
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.