Scratch Build a Vintage Fender Vibro-Champ

Discussion in 'Ampage Area' started by drrohle, Jan 30, 2016.

  1. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    So I've had this project in mind for years but now I've gotten up the nerve and expertise to possibly pull it off. I'm gonna meld three of my favorite hobbies... Electronics, Ham Radio and guitar playing into one project! The "Dean-O-Amp" or some other name (I'm up for suggestions by the way).

    I've been watching a channel on YouTube by a guy named "Uncle Doug" who just finished posting a multi-part series on scratch building a vintage amp. His was based on a Supro, mine will be based on the Fender Vibro-Champ. Fantastic instructor Uncle Doug is plus some great tips and resources on how to do it.

    Back in 1966 I built this speaker cabinet as a Jr. High School wood shop project and it has been with me all these years serving mostly as just a speaker box for my Ham radio rig. Cabinet-(F-Small).jpg
    That's my station call sign at the top.

    With a lot of help from Adobe Illustrator, I had our local metal shop bend me a chassis to fit inside the enclosure that will of course hold the electronics of the Vibro-Champ clone.

    The circuit is what's called a single-ended output employing (1) 6V6 vacuum tube. I'll explain the vibrato (actually a tremolo) circuit later. There will be a total of 4 tubes, the other three are (2) 12AX7's for pre-amp and tremolo plus (1) 5Y3 rectifier tube.

    The speaker I propose to use is a vintage 10" 1954 Zenith that is still in perfect condition. I may change it out for a vintage Jensen if it doesn't sound quite right but I'm fond of this speaker because it came out of my very first "Hi-Fi" record player in the early 60's.

    Speaker,-Zenith-(Small).jpg

    And here are a couple pix's of the newly finished chassis (sans all the holes)

    Chassis-(R-Small).jpg
    This is how it should sit in the 12 1/4" cabinet...
    Chassis,-Open-(Small).jpg

    Here is a rear-view drawing:
    Rear Drawing.JPG

    And a top view of the proposed control panel:
    Top Drawing.JPG
    As you can see, I'm just getting started so stay tuned for my progress reports...

    Here is the B-Model schematic I will probably use.

    bronco-VibroChamp_ab764_schem.gif
     
    Last edited: Jan 30, 2016
  2. Dead Roman

    Dead Roman Country Gent

    Dec 22, 2015
    Texas
    Do you have the wiring diagram? From looking at other hand wired amps, they look incredibly simple.
     
  3. BrianW

    BrianW Country Gent

    Oct 21, 2014
    Vancouver Island
    Interesting project. Blending the woodwork with electronics .... Now you are trying to tempt me into something similar.

    Have fun with that one !
     
    Jock_Hiltz likes this.
  4. Henry

    Henry I Bleed Orange

    Apr 9, 2014
    Petaluma
    Looking forward to this build. I like the pictures; already beyond my skill level.
     
  5. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Here are a couple schematics I will use. One is from Fender, the other is from MoJoTone.com.
    Very nearly the same. I will also add an adjustable "Negative Feedback Loop" circuit just to "tweak" the sound to my liking. Also I'm including a physical wiring diagram.
     

    Attached Files:

    Dead Roman likes this.
  6. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Oh I'll bet you could handle it. You can tell the woodwork was done by a Jr. High School Student! :)
     
  7. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    The parts are starting to come in. Had all the tubes except the 6V6 Output tube. Ordered the Tung-Sol version since it's suppose to give the vintage warm tone. So far, it's testing good in the tube tester I built in grade school! 6V6-Testing.jpg
     
    Last edited: Feb 9, 2016
  8. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    The 5Y3 Rectifier tube is New-Old-Stock and checking out good too. Ah... Nothing like the warm glow of Electric-Sex. 5Y3-Testing.jpg
     
    benjwri, Uniblob and j.s.c like this.
  9. englishman

    englishman Gretschified

    Age:
    64
    Apr 5, 2014
    Detroit
    Come on, man! How hard can it be? You could always hire someone to plug it in for the first time :D
     
    Sarah93003 likes this.
  10. Uncle Daddy

    Uncle Daddy Friend of Fred

    Jan 19, 2012
    Maldon UK
    I did something similar last Summer with a a kit based Champ. Loads of fun. Apart from the solder in the eye. And the burns. And the fire. Apart from those it was loads of fun!
     
  11. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Don't forget the life saving charge from the filter caps. (If you know where to place them in an emergency)!
     
  12. wabash slim

    wabash slim I Bleed Orange

    Age:
    72
    Feb 10, 2010
    lafayette in
    Can we call you "Sparky" now?
     
  13. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    You can call me anything you want. Just not late for the GIG! :)
     
  14. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Cutout mask.JPG Box-O-Parts.JPG Nail biting time, getting ready to make the cutout for the control panel. My electronics skills are much better than my woodworking skills are. Plus the rest of the hardware minus the power transformer & a few cap's n' resistors.
     
  15. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Control Panel cutout and test fitting of polished brass plate to overlay the chassis before drilling holes that will support all the controls & switches. Cabinet Cutout.jpg Polished brass plate was obtained from a local trophy shop.
     
  16. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Just received the Power Transformer and Output Transformer. All the major parts are in now, date code shows it was made 5th week in 2016. Now for the chassis drilling! IMG_0432 (Edited).JPG
     
  17. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Ran into a slight setback while routering the control panel cutout... Seems my half-century old rabbet joint was beginning to split on the upper part of the enclosure. So, after a bit of creative glueing and clamping, all is well and ready to begin punching holes in the chassis.
     

    Attached Files:

  18. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    Here is the "finished" IMG_0454.JPG control panel cutout and faceplate overlay. Plus some scratches for that "vintage" look.
     
    Jock_Hiltz and Sarah93003 like this.
  19. drrohle

    drrohle Synchromatic

    833
    Jan 3, 2014
    Hays, KS
    IMG_0478.JPG IMG_0479.JPG IMG_0485.JPG To get the holes in the right place I printed out (on 17" paper) an exact scale of where all the holes should go. Beginning with a spring loaded punch, small pilot holes and a new stepped drill bit that I just can't praise enough. Wish I had purchased one years ago for making large holes in sheet metal! View attachment 62904 View attachment 62905 View attachment 62904 View attachment 62905
    Then, follow the dotted lines to make the transformer cutout.
     
    MBERTHOLD and Sarah93003 like this.
  20. GreatGretsch

    GreatGretsch Country Gent

    Jun 25, 2008
    Pittsburgh suburbs
    Great work! Thanks for sharing.
     
    Klivvy likes this.
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