/ Register

  1. Win a Broadcaster or one of 3 Teles! The annual Supporting Member Giveaway is on. To enter Click Here. To see all the prizes and full details Click Here. To view the thread about the giveaway Click Here.

Champ Micro build thread

Discussion in 'Shock Brother's DIY Amps' started by dotbot, Jan 18, 2019.

Tags:
Page 2 of 2
  1. May 29, 2019 #21
    dotbot

    dotbot TDPRI Member

    Age:
    43
    Posts:
    37
    Joined:
    Jan 18, 2019
    Location:
    VT
    I've really enjoyed playing the Champ Micro for the last several weeks. It's a sweet practice amp. But I'd been bummed that I was getting a fairly strong hum when powered up, even without any input.

    I saw on this thread that a solution to the problem is to add an additional filter cap and that @robrob has changed the schematic for the Deluxe Micro accordingly.

    So I bought a JJ 50+50 uF at 500V can capacitor. This morning I disconnected the original 47 uF. You can see it sticking up in the photo but it is completely out of the circuit, and I clipped in the new 50+50. I followed the Deluxe Micro schematic for this since it is very similar, at this point, to the Champ.

    [​IMG]

    The good news is that it works! I'm happy to say that the hum is hugely reduced. I wouldn't say it's "dead quiet" but it is nothing to worry about anymore.

    The resistor between what is now B and B+1 was measured to be 462 ohms.

    New voltages:

    B: 395V
    B+1: 386V (used to be 399V)
    B+2: 275V (used to be 279V)

    Now I just have to figure out where I'm going to mount the can cap, solder up the connections, and put it all back together. :D
     
    jtcnj and sds1 like this.
  2. May 29, 2019 #22
    robrob

    robrob Poster Extraordinaire Ad Free Member

    Posts:
    8,158
    Joined:
    Dec 29, 2012
    Location:
    United States
    Yea, I need to update the Champ Micro schematic and layout to add the extra filter stage . . . and done.
     
    Last edited: May 29, 2019
  3. May 29, 2019 #23
    Paul-T

    Paul-T Tele-Holic

    Posts:
    511
    Joined:
    Nov 23, 2018
    Location:
    London
    thanks for the reminders, guys, as I have a basket all ordered at tube-town, just waiting for a late payment I'm owed before I press the button, and I see i'm one filter cap down.

    @robrob , thanks for all your amazing work. If poss, you need to update the Deluxe Micro Bill of Materials from 1 x 47uF to two, for any people not paying full attention (like me).
     
  4. May 29, 2019 #24
    robrob

    robrob Poster Extraordinaire Ad Free Member

    Posts:
    8,158
    Joined:
    Dec 29, 2012
    Location:
    United States
    Sorry about that Paul-T, I'll update it.
     
    Paul-T likes this.
  5. May 30, 2019 #25
    Meteorman

    Meteorman Tele-Holic

    Posts:
    999
    Joined:
    Dec 23, 2012
    Location:
    State College PA
    you da man, Rob... don't forget that 470/2w voltage dropper between 'em.;)
    I'm ordering parts for a Micro Deluxe build right now.
    went with the Hammond 290CAX and 1750A.
    Plus SS rectifier.
    Think I can get a head unit put together under $250 all in.
    I'll post pics once things get rolling.
     
    robrob and Paul-T like this.
  6. May 31, 2019 #26
    Paul-T

    Paul-T Tele-Holic

    Posts:
    511
    Joined:
    Nov 23, 2018
    Location:
    London
    thanks for the 470 ohm reminder, I missed that too.

    Toroidal PT for me, trying to keep my costs well down. Just need to find someone who'll swap their 8 inch Jensen for my 10 inch Jensen and I'm home.
     
    robrob likes this.
  7. Sep 15, 2019 #27
    ouaouaron

    ouaouaron TDPRI Member

    Posts:
    33
    Joined:
    Jun 25, 2015
    Location:
    Saint Louis

    I really like your homemade chassis (oriented toward the back not up like Fender and like the wood cab.
     
  8. Oct 9, 2019 #28
    ouaouaron

    ouaouaron TDPRI Member

    Posts:
    33
    Joined:
    Jun 25, 2015
    Location:
    Saint Louis
    what is the length and the height of the chassis? 10" by 2"?
     
  9. Oct 21, 2019 #29
    dotbot

    dotbot TDPRI Member

    Age:
    43
    Posts:
    37
    Joined:
    Jan 18, 2019
    Location:
    VT
    Sorry I didn't see this question!

    The chassis is 12" wide by 2" high by 5" deep.
     
Page 2 of 2
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.