Joyo Sweet Baby Tweed Champ clone

Discussion in 'Amp Central Station' started by teza, Jan 12, 2016.

  1. teza

    teza TDPRI Member

    Posts:
    57
    Joined:
    Aug 20, 2012
    Location:
    France
    Can't wait to receive my cap.
     
  2. engineer

    engineer Tele-Meister

    Posts:
    215
    Joined:
    Feb 26, 2013
    Location:
    Sweden
    Great news!

    But there is a clear lack of sound clips before and after the "mod". Like putting the volume on 4 or 8 playing it before and after adding the cap.
    Let us hear the difference.
    Or, why not put it in a switch?
     
  3. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Yeah, clips might have been a good idea, but I don't think a switch is necessary. This amp is meant to have that cap and doesn't sound right without it.
     
  4. teza

    teza TDPRI Member

    Posts:
    57
    Joined:
    Aug 20, 2012
    Location:
    France
    Just put a 25uf and turn it in a monster !!!
    Will a 22uf soon to have less bass and keep you posted.
    Cheers.
     
  5. teza

    teza TDPRI Member

    Posts:
    57
    Joined:
    Aug 20, 2012
    Location:
    France
    Just find a sprague 22uf radial witch sould sound better.
     
  6. Alamo

    Alamo Doctor of Teleocity Silver Supporter

    Posts:
    10,699
    Joined:
    Nov 15, 2006
    Location:
    Berlin
    22 uF vs 25 uF ? not worth the hassle.
    You won't be able to hear any difference.
    use the interactive calculator to actually see what the outcome will be:
    https://www.ampbooks.com/mobile/amplifier-calculators/cathode-capacitor/calculator/

    22uF - gain @ 82 hz = 35,42 dB
    22uF - gain @ 10 kHz= 35,46 dB

    25uF - gain @ 82 hz = 35,43 dB
    25uF - gain @ 10 kHz= 35,46 dB
     
  7. teza

    teza TDPRI Member

    Posts:
    57
    Joined:
    Aug 20, 2012
    Location:
    France
    Thanks.
     
  8. Alamo

    Alamo Doctor of Teleocity Silver Supporter

    Posts:
    10,699
    Joined:
    Nov 15, 2006
    Location:
    Berlin
    I wanted to record that Brown Sugar clip again.
    I had said that the level was between 9 and 10 on the amp then, now after the "mod" this level is just too freakin' loud in my appartment.
    I'd seriously get in trouble with the neighbours - it's a huge jump in gain.
    I'd guess 7 on the dial (noon) is the about the same as it was on 9-10 before.
     
    teza likes this.
  9. engineer

    engineer Tele-Meister

    Posts:
    215
    Joined:
    Feb 26, 2013
    Location:
    Sweden
    I have to say that the amp sounds really good as it is (unmodified), but I can't say it would sound any worse with the modification. I mean, I still have no clips. o_O

    Haha...well, we all have that problem, at least us who lives in an apartment. I recorded my first clip for the other thread at home during a weekday (I don't work office hours). But it't share our was only for a few minutes.

    Maybe you can do it and be real quick about it.
    Otherwise I have a rehearsal space where I take to put it though it's paces (plus I needed to break in that speaker).

    Hopefully the rest of you who made the mod doesn't share our habitation type and can record som clips.

    Actually, I haven't really understood what the mod does.
    Does it just make the amp louder or does it drive the pre amp harder, making headroom smaller and breakup earlier?
     
  10. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Uncle Doug (look him up on YouTube! ) talks about it. Without that capacitor, the cathode becomes 'constipated' to use uncle Doug's words. The capacitor allows the electrons to flow freely, and increase gain.
     
  11. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    I used it last night for the first time at a gig! Medium sized bar, playing in a duo with the other guy playing acoustic. I brought a Les Paul, and the amp was mic-ed up. I set the volume to about 8 and then steered everything from the guitar.
    First impressions: the Les Paul was perhaps the wrong guitar for this amp. Although the solos sounded fantastic, it was a bit muffled on the neck pickup, and even my vintage style humbuckers drove it into overdrive a bit too easily.
    I think it would have sounded a bit better with my Tele. Also, I think I'd have got a better sound with my 12" cabinet.
    Still, on the whole I'm happy! It's a very musical little box .
     
    jiri_c likes this.
  12. engineer

    engineer Tele-Meister

    Posts:
    215
    Joined:
    Feb 26, 2013
    Location:
    Sweden
    Actually I have seen his videos when I was thinking about buying an old Champ or building one of my own.
    Is there a specific video where he talks about this or is it one about the Champ? I looked through one where he build a champ out of left over parts, but couldn't find it.

    Great to hear your gig went well. Understatement on the guitar, though. Especially given this forum...
    Did you get to crank it? ;)
     
  13. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Yes, I cranked it . It sounded better turned down to about 8 though, more than enough gain for me. The guitar is an Edwards Les Paul copy, with leosounds PAF style pickups (made in Germany). The pickups aren't wax potted and fairly bright, and I've put them out of phase, a la Peter Green (still on the fence about that though).
     
  14. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
     
  15. engineer

    engineer Tele-Meister

    Posts:
    215
    Joined:
    Feb 26, 2013
    Location:
    Sweden
    Thanks for pointing out the video.

    Now I get the microfarads part. But when I have been looking at caps there is also a Volt value specified together with the microfarads value.
    What does that mean in this context?
     
  16. Alamo

    Alamo Doctor of Teleocity Silver Supporter

    Posts:
    10,699
    Joined:
    Nov 15, 2006
    Location:
    Berlin
    It just specifies how many volts the cap can handle.
    if you send 50 Volt into 25 V cap - it will melt/blow/break whatever.

    the voltage on that part of the amp is quite low, the big black caps are rated a lot much higher. probably 450 V or so.
     
  17. AJBaker

    AJBaker Friend of Leo's

    Posts:
    2,927
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Yup, that's just the safe maximum voltage it can handle. Has no effect on sound.
     
  18. engineer

    engineer Tele-Meister

    Posts:
    215
    Joined:
    Feb 26, 2013
    Location:
    Sweden
    Thanks!

    So I just need a sufficient voltage cap with the microfarads of my choosing?
    If I pick a 100V or 450V as no effect on the sound nor the safety?
     
  19. elpico

    elpico Tele-Holic

    Posts:
    739
    Joined:
    Sep 14, 2011
    Location:
    Vancouver BC
    No effect on tone, but a big effect on the physical size of the capacitor. A 400v capacitor would be about four times the size of a 6.3v one. There's less than 2 volts on this point so either is going to work fine.
     
  20. sleazy pot pie

    sleazy pot pie Tele-Afflicted

    Posts:
    1,005
    Joined:
    May 31, 2014
    Location:
    austin
    I know this is an older thread, but i just got one of these amps and want to ask if this is the correct capacitor to use for the cathode bias?
    I could have the name wrong, but they mention 22uf 25v cap adding more gain, this is the cap that isnt in the diagram for 5f1's but is present in most if not all tweed champs. Screenshot_2017-06-09-15-55-59.png
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.