5F1 First Build, 2 Questions

Discussion in 'Shock Brother's DIY Amps' started by Rock_Glenn, Aug 10, 2014.

  1. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Wiring up a boothill Amps 5F1 and Dave sent three, three-terminal jacks. On the speaker jack How should I wire the "switch" terminal? I would assume grounding it would cause more damage should the speaker come unplugged sending the positive from the OT directly to ground. Or should I put a 4 ohm resistor in there to ground as protection?

    Also I'm using a classic tone 40-18030 OT, The Red wire common is sent to the positive side of the first filter cap, and the blue to pin 3 of the 6v6, correct? It seems strange to me to have a common at +340V.

    I also used the Blue 8Kohm primary, is this Ok with the 4ohm output?

    Thanks in advance for your help.

    I'll post pics before firing it up.
     
  2. dr.chevalier

    dr.chevalier Tele-Holic

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    Not sure about the OT primary, but on the speaker jack, black will go to ground AND be jumpered to the shorting tab. Your other primary (yellow for 4 ohm) is wired to the tip.
     
  3. hackworth1

    hackworth1 Friend of Leo's Vendor Member

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    Looking forward to the pictures.
     
  4. Rock_Glenn

    Rock_Glenn TDPRI Member

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    I was about to wire it that way, but Wouldn't it make more sense to put a 5W low-resistance (1-8 ohm) resistor between switch and ground so there is a load, should the speaker be unplugged?

    Unless someone can offer a good reason not to, it's leaving me scratching my head as to why this isn't the norm.

    And if someone can answer the OT primary questions I would really appreciate it.

    If it helps, this link has the specs for the OT: http://www.classictone.net/40-18030.pdf
     
  5. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Thank you, and I apologize I started responding to the above before you posted.

    I'll post pics soon.
     
  6. Killin5

    Killin5 Tele-Meister

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    I used that OT transformer on my 5F1. Your plan for wiring it up sounds correct. I ended up using the 5K ohm instead of the 8K ohm wire, but I think either would work. I stared with the 8K then swapped over to the 5 as I was troubleshooting hum issues. Once I got things working I liked it so didn't switch back.

    You can also wire the COM\Red from the OT directly to Pin 8 of the 5Y3. I found this easier to do while I was connecting and disconnecting in troubleshooting.

    If you cant guess, I had to do a lot of troubleshooting. :lol:
    View attachment 5F1layout40-18019.pdf
     
  7. Telenut62

    Telenut62 Poster Extraordinaire

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    Correct, the 18031 OT has the blue and red in reverse. 4ohm is ok, from trial and error I prefer the 5Kohm primary, especially if the amp is working hard.
     
  8. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Thank you. I tried wrapping my head around the benefits of the different resistances on the primary side, and decided to go 8K. Unfortunately I had already cut the 5K off and taped it. Next time I suppose.

    Here are the pics, I tried to get everything, but after a quick review I realize it may be hard to see the tube socket wiring. I forgot to take a picture of the underside of the board, but I'm rather confident on the wiring there. If something came disconnected whilst mounting the board, that's another story.

    But if you see anything out of place feel free to call me stupid. I haven't fired it up as I'm waiting on a rectifier tube to come in. (I thought I had one).

    The grounding bus started out nice and straight until I realized the input jacks would hit it so I bent it as you see here.

    I also oriented the output tubes a bit different than normal, rotated a 1/4 turn.

    [​IMG]

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    [​IMG]
     
  9. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Those were really small.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  10. Telenut62

    Telenut62 Poster Extraordinaire

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  11. Glen Smith

    Glen Smith RIP

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    I hope my eyes are playing a trick on me. In the attached photo it looks like you have the signal ground hooked up to the AC on/off switch!
     

    Attached Files:

  12. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Hah, fortunately that signal ground makes a hard right under that black wire, and is a solid 1/2" away from either terminal on the on/off switch. You can see the other black wire sneaking in at the lower left, and that is actually the wire making contact there.

    And Telenut, the Jacks (plural) are the input jacks, is that what you were looking at? I can post a closeup of the output jack if necessary. I wired the red/yellow (negative feedback) and yellow from OT (4 ohm) to Tip. I then wired the black from OT (common) to switch and ground.

    thanks for the extra sets of eyes on this.
     
  13. Glen Smith

    Glen Smith RIP

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    Yeah, I had a closer look at the photos and my eyes were tricking me. Whew! Carry on.:lol:
     
  14. Telenut62

    Telenut62 Poster Extraordinaire

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    Ah yes, had a brain snap...someone else had a duo jack output.....men are no good at multi tasking :lol:
     
  15. boredguy6060

    boredguy6060 Poster Extraordinaire

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    in the picture, the cathode resistor 470ohm looks to be touching the bypass cap.
    It can get real hot, so some space for ventilation is needed.
     
  16. Blinky

    Blinky Tele-Meister

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    People call it the "Hammer" and I don't know why
    The bus bar looks like it could be touching things it shouldn't be. It's probably just real close but might be worth checking.
     
  17. Rock_Glenn

    Rock_Glenn TDPRI Member

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    I gave the bus bar and bypass cap a bit more breathing room. They weren't touching, but may have been too close.

    If I could start over I'd do some things differently. After squeezing things into such a small space it changes your perception a bit.

    Thanks for taking a look, once the 5Y3 comes in we'll try making some music.
     
  18. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Got the tubes in, fired her up and it sounds great. Hardly any hum at all, even up the dial.

    Thanks again for taking a look.

    [​IMG]

    [​IMG]
     
  19. dr.chevalier

    dr.chevalier Tele-Holic

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    Kudos to you, sir!
     
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