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Build a 5F2A inside a Frontman 15G?

Discussion in 'Shock Brother's DIY Amps' started by James Knox, Oct 5, 2020.

  1. James Knox

    James Knox Tele-Holic Silver Supporter

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    If I were to repurpose a Fender Frontman 15G “donor cab” as a 5F1 or 5F2a, how would I hang the trannies on the chassis?

    I’m looking for any suggestions on turning this non-functional SS amp into a Champ or Prince.

    3EA6823D-05BE-42BB-84D6-C5989952611A.jpeg 4B395CB8-874F-4A15-AC5E-3DDBAE9AB123.jpeg E6638AA0-9A24-4DB2-A690-48FB1D582FF3.jpeg
     
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  2. Dan_Pomykalski

    Dan_Pomykalski Tele-Meister

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    I’ve been considering doing the same. The best way I’ve thought of was to buy a small enclosure and attach it to the chassis. But at that point I figured why bother using that chassis anyway, which is why it’s still sitting collecting dust.
     
  3. hamerfan

    hamerfan Tele-Meister

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    I used a SS Bronco for a 5F1. Imo its not worth the extra labour for the fitting. Sell the Frontman and get a nice big size Tweed cab. Hint: A 12 inch speaker (or even a 10 incher) sound much - i mean much - nicer than these tiny 8 inch of any brand.
     
  4. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Plus tube socket holes, plus coming up with a new faceplate. I would think it's much easier to get the right chassis from the start to keep things neat.
     
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  5. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    My $0.02
    If the frontman control panel is to be retained, I would think the most logical decision would be to have the original control panel with an umbilical cord to a chassis in the bottom of the cabinet.
     
  6. glenlivet

    glenlivet Tele-Afflicted

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    Bad chassis choice....unless you want to do some metal working....or have some serious time to kill.

    It looks like you could flip it over like this.... (remove the big heat sink)

    upload_2020-10-5_13-27-39.png

    Bend the front faceplate back so that the angle is right when you put it back in the cabinet. You might have to nip off those two tabs that will now be on the "top" of the chassis tray.

    Bending that steel isn't as easy as you think it is.......unless you have a metal break sitting around.


    Here is what I did to a Frontman 25r... If you look at the back of a normal Frontman 25r you can see what I did...
    traymounted1.png

    tray13_1_orig.png
     
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  7. James Knox

    James Knox Tele-Holic Silver Supporter

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    Good comments and observations all around - thank you!

    The Frontman belongs to a friend that has sentimental attachment to it. It died, so he was thinking of turning it in to a small tube or Micro Amp. I’m trying to see if it is possible.

    My first thought was maybe something like a BF Champ, but the chassis is “upside down”. Would it even hold the Trannies? Maybe a RobRob Micro Champ with Diode Rectifier?
     
  8. Asmith

    Asmith Friend of Leo's

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    If the unit is sentimental I'd recommend turning it into an actual micro. Use a 12AU7 as a power value, the project will cost considerably less since you can buy smaller trannies and it will be easier to fit on the chassis.

    I built one into a very small enclosure before about the size of 2 normal pedals or one of Strymon's larger pedals.

    20200404_140552.jpg

    I would recommend something bigger if you don't have a lot of experience dealing with small and fiddly electronics. But it's a good demonstration of how low profile the trannies can be for such a small amp. You could even build something similar to the above and tuck it into the chassis but have wires running to the faceplate.
     
    Last edited: Oct 5, 2020
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  9. tubegeek

    tubegeek Friend of Leo's

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    Then the legends will be upside down on the front panel.

    You could augment the original with a chunk of structural C-channel mounted to it, such as are used in building framing.
     
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  10. Dan_Pomykalski

    Dan_Pomykalski Tele-Meister

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    Oh yeah. This would be the way to go. Kinda like the Excelsior.
     
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  11. archetype

    archetype Fiend of Leo's

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    Buy a box chassis with a slant front. That will give you the correct foundation. The existing faceplate can be reused, if that's important in the equation.

    Nice that you're doing this for your friend.
     
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  12. Dan_Pomykalski

    Dan_Pomykalski Tele-Meister

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    I was also considering getting a cover plate like one of these: https://www.tubesandmore.com/search/node/Cover plate?sort=price_low_to_high

    Again, I never really got past the idea stage, so I don’t really know how well it’d work.
     
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  13. glenlivet

    glenlivet Tele-Afflicted

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    Glue / tack / screw a couple cleats into the frontman cabinet. Set the tray on the cleats so it slides into place.
    Like I said...using the existing tray is definitely not the "easy" way. It's going to require some effort to re-engineer.
    Trannies don't *have* to mount on the tray....they *could* be mounted to the bottom of the (wood) cabinet, and HV wires run up to the tray.
    Like I said....not easy....but if you want to put time and effort in..... probably doable....
     
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  14. zook

    zook Friend of Leo's

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    I have always, even after converting them to open back, found the Frontman 15 cabinets to be awful,
     
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  15. James Knox

    James Knox Tele-Holic Silver Supporter

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    *** Project has Been Scrapped ***

    Feasibility Study has deemed the project a no-go!

    Thanks everyone for your valuable input and advise!
     
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  16. gusfinley

    gusfinley Tele-Afflicted

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    A few years back I was trying to find good cheap "donor amps" to convert to handwired classic amplifiers.

    I converted two Vox Pathfinder 15's into AC4 (EF86 plus top boost) circuits and was looking for some Orange, Marshall or Fender amps to convert.

    Sadly, the amount of Analog practice amps has dwindled over the years.It's hard to find one with even a 10" speaker any more and the cabinets and speakers are of very poor quality!

    I would pay money for a broken AC4C1-12 or AC10C1 to convert, though!

    Oh, and my own feasibilty study has found that a Vox Pathfinder 10 could be converted into a mini AC4 head unit/practice amp.
     
    Last edited: Oct 6, 2020
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  17. James Knox

    James Knox Tele-Holic Silver Supporter

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    I had a Pathfinder 15R for several years and finally sold it cuz I never played through it. Wish I had it now as a donor amp. Think I got $100 for it, lol.
     
  18. mjcyates

    mjcyates Tele-Meister

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  19. James Knox

    James Knox Tele-Holic Silver Supporter

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  20. printer2

    printer2 Poster Extraordinaire

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    I think the project is not a bad one. You just have to think of what you have and what is missing. Also thinking outside the box doesn't hurt. what you need to have is another piece to your chassis. One that follows the two red arrows to the back in line with the back of the heatsink (which will be removed), then goes down 90 degrees till it hits the existing metal. Then a 90 bend again toward the back. The (I am guessing 3/8") last bend is used to screw the 'bottom' plate to the original. Also the front edge, rather than starting where the arrows do would overlap the bottom lip and again be screwed together.

    The two little tabs used to screw the chassis to the cabinet could be cut off and then wood rails mounted to the cabinet for the chassis to sit on. Or the tab area of the new bottom notched out and mounted to the chassis as before. A piece like this would be nothing for a sheet metal shop (heating air conditioning shop) to do, they could have a piece of scrap and maybe do it for $20. Or go to a vocational high school.

    [​IMG]

    The only real downside would be that the circuit would be mounted to the new piece and to get to the inside it would have to be removed from the original. That would entail removing the components on the front plate. A bit of a pain but once built and running not really an issue.
     
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