First Build, 5F11 Mojotone Kit for 10th anniversary

Discussion in 'Shock Brother's DIY Amps' started by Potatocaster, Jun 30, 2019.

  1. Potatocaster

    Potatocaster TDPRI Member

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    Hi folks,
    Longtime reader, first time poster. I’m embarking on a build for my 10th anniversary (gift from wife) and am excited. I’ve built and designed a few simple pedals, but this is my first amp rodeo.

    I plan to make the amp out of select pine 12inch boards, with finger joints. I’ll then cover it in paisley cloth that has our wedding colors.

    I plan on using two 8 inch 16ohm Warehouse speakers for a unique twist on things.

    I have all my parts and have the components on my board. Next up I plan to make a cardboard template and build the cab. Never done box joints so I’m making a router table and testing on a lot of small boards.

    Photos as I go can be found here: https://photos.app.goo.gl/yMxrrnGcE1CrikUE9
     
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  2. Paul-T

    Paul-T Tele-Meister

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    Board looks great so far. Do post a few pix inline.
     
  3. King Fan

    King Fan Friend of Leo's Ad Free Member

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    ^^^Posting pics here really makes your thread work, and it’s easy. On a computer you just drag the image jpgs into your post, and choose thumbnail or full size. On the mobile app IIRC there's an icon to add images.
     
    Last edited: Jul 1, 2019
  4. Bob Arbogast

    Bob Arbogast Tele-Afflicted

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    The 5F11 is a good choice for a first build. It's a fairly simple and great sounding circuit. Best of luck with it! And, yes, do keep us posted.

    FYI, there is a better bias arrangement than the stock version. It's essentially a BF bias circuit, with a 100uF filter. This is stable and has a wide adjustment range. You can also add an additional 50uF filter from the wiper of the bias pot to ground. This helps to limit background pulsing from the trem circuit. Finally, if you want slower available trem speed, you can use three .02uF caps in the oscillator instead of the stock mix of .01 and .02 caps.
     
  5. jsnwhite619

    jsnwhite619 Friend of Leo's

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    I just sold my 5f11 cab - I wasn't playing it much - but I've really been think about making the next one 2x10 for it. I had a 12" but since the chassis has been out, I hooked to my Raging Cajun cab and it sounded incredible.

    Sent from my XT1585 using Tapatalk
     
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  6. Bob Arbogast

    Bob Arbogast Tele-Afflicted

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    I've had the 5F11 circuit (sometimes with higher power) in 1x10, 2x10, and 4x10 combos. All of them sounded great.
     
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  7. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    This should be fun; I look forward to seeing the paisley cover to your cab!
     
  8. jhundt

    jhundt Doctor of Teleocity

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    have you ever considered that it might be a good idea to relax a bit, and do one thing at a time?

    Building router tables and learning how to make box joints is a whole fun and entertaining learning thing. It deserves some time and attention.

    Building an amp is fascinating, and highly rewarding. It might be best to work on that without the distraction of learning how to do all the woodwork.

    well, that's how my brain works, anyway.
     
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  9. Potatocaster

    Potatocaster TDPRI Member

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    I tend to go on all cylinders on projects like this I guess. I love learning new things and how to make stuff.

    I've been attempting to get a good joint going. Trying a few different routes and jigs. I had tried a sled jig but the pieces kept getting loose when routing even when clamped.

    Thank you everyone for the kind comments and tips. I've been swamped at work and hadn't gotten back to posting. I will 100% get some inline pics up and look into that alternative bias circuit. Sounds like a great option to add.
     
  10. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Bob, very interesting. Do you have a diagram or pic? Maybe this has to do with wiring the bias pot as a variable resistor, while some schemes wire it as a voltage divider? Anyway, one picture etc etc. Trem thump is a real issue in some of these amps.



    Sent from my iPad using Tapatalk
     
  11. JuneauMike

    JuneauMike Friend of Leo's

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    @Potatocaster, the 5F11 is a terrible choice for a first build as the tremelo effect comes from the bias of the power tubes and so its complicated and fickle and your component values, final voltages and your bias all interact to greatly affect your playing experience. If it's all correct, you've got luscious sounding amp, if its' wrong you don't have a 5F11.

    Otherwise it's a great amp and it was my first build. I built it paint by numbers the first time around, not understanding amps and got a less-than-perfect outcome. I rebuilt mine a few years later when I had more experience and a 5F1 under my belt and got outstanding results. It's my main amp now.

    But this is what you've got to work with and you can still build an excellent amp here. There's several build threads on the 5f11 that will be helpful and Rob's site on Fender amps is a great resource. Pay particular attention to the problems other people encountered and how they solved them. Also, Uncle Doug has a great YouTube video tour of the 5F11 that you would do well to memorize.

    This is a fantastic amp. If you've never built an amp before I'd strongly encourage you to read everything you can about the Fender tweed circuits, this amp in particular, and amp building in general. If you find yourself spending way more time reading and researching than actually assembling then you are doing it right. Remember, amps are forever so be patient.

    Also, build it dead stock first. Make mods later. Don't borrow trouble.
     
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  12. JuneauMike

    JuneauMike Friend of Leo's

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    I built a very crude version of this jig and after a few test pieces and some fine tuning, I got very good joints slightly proud of the box surface. He recommends an up-cut spiral bit but I used a trim router bit. In the end its going to be sanded and have a cover put on it so perfect is the enemy of good enough.

     
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  13. Bob Arbogast

    Bob Arbogast Tele-Afflicted

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    In my 5F11s, the bias circuit is AB763-style, with the addition of a 50uF cap from the bias pot wiper to ground. Note: the ground connection for the main bias cap is at the bottom of the photo.


    As far as tremolo thump, the additional cap helps with that. It also helps to use a footswitch to turn the oscillator off when you aren't using the trem.
     
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  14. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Thanks, Bob. I appreciate the picture, but as so often with amplifiers, the wires get in the way. :) Let me see if I'm seeing straight.

    I take it the AB763 bias pot is what Rob diagrams below. So if I understand, your cap comes off the wiper along with the lead that carries the bias to the 220ks, but the cap's other lead goes to ground?


    upload_2019-7-11_15-20-0.png
     

    Attached Files:

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  15. Chicago Matt

    Chicago Matt Friend of Leo's

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    Lots of fun ahead, and a big reward at the end. What's not to like? Enjoy it!
    I'll be looking forward to see how it's coming along.
     
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  16. Potatocaster

    Potatocaster TDPRI Member

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    Thank you! I'll investigate this today. I've been trying to devour as much as I can on these things. I'll likely go with the kit. I had originally planned a champ build buy the addition of trem was too tempting.
     
  17. JuneauMike

    JuneauMike Friend of Leo's

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    Yep, common sense and pretty much every DIY amp builder out there told me to buy a Champ first. But I wanted an amp that I could use outside the home as well as in the living room and I couldn't see a use for a tiny Champ at the time. Live and learn.
     
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  18. Bob Arbogast

    Bob Arbogast Tele-Afflicted

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    Yes, that's correct about the 50uF cap (+ lead to ground!).
     
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  19. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Right! Good reminder. Bias is 'backwards...'
     
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  20. Potatocaster

    Potatocaster TDPRI Member

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    Curious--i have the fixed bias build. Is the consensus that going adjustable is a better option for a good experience?
     
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