Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

New (and first) build: 5f2a Tweed Princeton

Discussion in 'Shock Brother's DIY Amps' started by theprofessor, Nov 2, 2017.

  1. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Well @King Fan 's 14-2 Romex-to-bus method works quite well, if I may say so. I got the bare copper out of the Romex, lickety-split. Then I took it down and put it in one of my vise ends of my Sjöbergs woodworking bench, grasping the other firming with needle-nose pliers, and twisting on its longitudinal axis, as @tubeswell suggested. That method works great to straighten it! Then I rubbed it down with alcohol, fired up the soldering iron, and covered it with tin. Now I've got 2 feet of bus bar (I don't know what gauge it is; I'm no good at eyeballing wire gauge) that has already been tinned. It's not perfect and smooth, since you kind of have to "paint" it on with the iron. But it'll work!
    IMG_9463.JPG
     
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  2. King Fan

    King Fan Friend of Leo's Ad Free Member

    Jan 1, 2013
    Salt Lake City
    Got more? I hafta say I like Tubeswell’s ‘straighten’ idea a lot better’n my ‘all-tinned’ idea. Copper tarnish between solder points would look just fine. :-/
     

  3. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Got some more work done this evening. I'll be able to finish the eyelet board tomorrow, when I get a couple of metal oxide resistors in. I'm beefing up the wattage on both the voltage-dropping resistors to 3W.

    I decided to use these 8-32 nylon machine screws to mount the board in the chassis. I can use two nuts on it, one being a spacer that is the same height as the keps nut on the OT.

    IMG_9471.JPG

    I also got another alpha pot for the volume control so the tone and volume pot shafts would match in length (remember when I mentioned borderline OCD?).

    IMG_9476.JPG
    IMG_9473.JPG
    I put those solid state diodes in on the rectifier, as @tubeswell and @King Fan and @RLee77 suggested. As @tubeswell said, this is definitely something to do outside the chassis!
    IMG_9474.JPG

    And finally, I decided to go with a NOS bakelite fuse holder that I got from Tube Depot.
    IMG_9472.JPG
     
    Last edited: Nov 8, 2017
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  4. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Yeah, it's no big deal. It could come off pretty easily, too, I imagine. But it's so cheap it was worth a try. Is it the look that offends? :)
     

  5. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Hey @King Fan and/or @keithb7 - Do you happen to have pics of your 5f2a over in the fuse, lamp, and switch area? If you do, that'd be helpful to me.
     

  6. keithb7

    keithb7 Friend of Leo's

    Age:
    46
    Jan 9, 2010
    Western Canada
    This one has switchable NFB:
    [​IMG]

    Mind the burnt wire covering. I fixed that later. LOL. It's easy to touch stuff with the hot iron in tight quarters.

    [​IMG]
     
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  7. keithb7

    keithb7 Friend of Leo's

    Age:
    46
    Jan 9, 2010
    Western Canada
    Here is another one different I did. A Weber kit.

    [​IMG]

    [​IMG]
     
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  8. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Alright, everyone. Please check my work on the front and back of the eyelet board. Other than putting in some new 3W voltage-dropping resistors this afternoon, this represents what I think is a complete board. Please respond with yea or nay. And in the background, you'll see some papers I'm supposed to be grading and some manuscripts I'm supposed to be editing... [for the back of the board, see now post # 162, where I've removed a jumper that shouldn't have been there]
    IMG_9477.JPG IMG_9478.JPG
     
    Last edited: Nov 9, 2017

  9. keithb7

    keithb7 Friend of Leo's

    Age:
    46
    Jan 9, 2010
    Western Canada
    While looking for some photos I found this one. The rarely seen shot from the behind the speaker baffle board. I realized here that I only had the head of the machine screw, used to mount the OT, under the fibre board. You can leave the longer end of the screw exposed through the bottom of the chassis, and have the nut on the outside. In your earlier pic you have the nut on the inside under the board. It appears that either you found an exact length screw so it did no protrude up under the board. Or maybe you cut the screw off flush with the nut? There are no exposed threads in that scenario. There is zero margin if that nut were to ever work lose. If you leave it as you show it, I'd consider putting some lock-tite on the threads.

    The other option is to turn the screw the other way and point threads out through chassis as seen in my pic here below. You can also see where I did the same with the plastic fasteners I used to mount the board. This one is a 5E3, however illustrates my thoughts.

    [​IMG]
     

  10. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Thanks a lot, keithb7! That photo and your description is very helpful. I think that's a really good idea to flip the machine screw around the other way. It means that the OT could be tightened, if necessary, even if the eyelet board covers over the screw head inside the chassis. I'm going to go over to the hardware store and get some longer machine screws, too. You're right about needing to have the threads pass all the way through the nut. I was trying to use what was in the kit, but I'll just replace it. I've done that with almost everything else! :) Thanks again!
     

  11. King Fan

    King Fan Friend of Leo's Ad Free Member

    Jan 1, 2013
    Salt Lake City
    I don't seem to have a pic of that area after it was done -- back then I seemed to think the board was what it was all about and focus all my attention there.

    6G2 - 1 (10).jpg

    It's (a ton) less crowded, and the fuse and switch are on the back wall, but this pic from my last build shows the basics --

    • Green wire should be cut longer than the other two and loop to a totally separate, unique, bomber ground point. (Order: serrated washer under crimp-on-then-soldered ring under the keps nut, which is also locked with thread locker.)
    • Black wire goes (in order) to fuse, then switch, then to one of the PT primaries (it doesn't matter which).
    • White wire goes to the other PT primary. (My primary was that black/brown pair -- yours is probably a single wire, usually black?)

    Speaking of Mojo, I used an **ungrounded** side lug (on the right in pic) of one of those Mojo terminal strips -- I didn't used them at all in my Mojo PR -- as a tie point to join the white wire to the PT primary. (I cut off the other side lug and the center lug, and ran a small through the center 'ear' to fasten it down). Some physical tie point is easier and sturdier than a splice-in-space. To be tedious but clear, even though I *didn't* use the terminal strip as a ground point, I did use on lug as an ungrounded (duh, of course) point to tie household neutral to PT primary.
     
    Last edited: Nov 9, 2017

  12. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Thanks, @King Fan , for the description. Though you mentioned a pic of some kind, none came through on the post. Also, can you look back at my post of my finished eyelet board, front and back, before I mount it in? I want to get a green light from others on that before I forge ahead. Thanks!
     

  13. King Fan

    King Fan Friend of Leo's Ad Free Member

    Jan 1, 2013
    Salt Lake City
    Ah the forgotten attachment. Bane of my existence. I edited it in above.

    And I'm gonna let smart people check your board. I never trust my eye even on my own builds. Let me think about my new flip-the-pic trick to look at your backside wires.
     
    Last edited: Nov 9, 2017

  14. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    There you go, @keithb7 . All better. Thanks for the tip!
    IMG_9480.JPG IMG_9482.JPG
     

  15. FenderLover

    FenderLover Friend of Leo's

    Jun 11, 2009
    Minnesota
    Check the back-side pic on post 148 - did you short the 10K between the second and third filter caps?
     
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  16. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Good eye, @FenderLover ! Yes, I think I did. I'm getting the replacements in the mail today. I'll be changing both of those voltage-dropping resistors to 3W. So, yes, I do think there's an issue there, but I plan to resolve it this afternoon.
     

  17. King Fan

    King Fan Friend of Leo's Ad Free Member

    Jan 1, 2013
    Salt Lake City
    I wait for eagle-eyes like FL who can do this visually. To make sure I'm reading the dotted lines right, I like to make a flipped view of the layout -- I recolored mine to match your wire colors. You'll already know FL's extra (shorted) jumper is second from right at the bottom.

    5f2a backside traces.png
     

  18. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Impressive (in a Darth Vader voice), @King Fan ! I love that graphic you made up. You've got skillz! Yes, I knew I had cut the leads too short on that one almost immediately. I'm fixing it as soon as the post arrives in a couple of hours.

    The more I look at all these layouts and schematics, the more I see why people say to rely on the Fender schem and layout and then to use @robrob 's grounding scheme. The most important docs for me have been the Fender docs and also @robrob 's 5f1 layout.
     

  19. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    This is what I was tryin' to say, @King Fan :
     

  20. King Fan

    King Fan Friend of Leo's Ad Free Member

    Jan 1, 2013
    Salt Lake City
    "Darth, you are my, um, Professor...?"

    Re 'shorted', are we talking about the same thing? I think FL meant you added a jumper in the right lower corner, 'shorting' the 10K dropping resistor on the front. Not 'shorted' in the other sense. IIRC the guys thought your short leads weren't too short as long as they reach the eyelets.
     

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