Harvard 5F10 Build

Discussion in 'Shock Brother's DIY Amps' started by mjcyates, Nov 14, 2018.

  1. mjcyates

    mjcyates Tele-Meister

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    Been thinking about building a Harvard 5F10 for a while and came across a chassis on ebay for a decent price so I pulled the plug. I have the Fender layout that is commonly available. I have seen a couple of board layouts on this forum. Does anyone have a good complete layout including offboard wiring similar to the layouts that Rob Robinette has on his site for the 5e3?
     
  2. JuneauMike

    JuneauMike Friend of Leo's

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    I would love it if someone could talk @robrob into doing as thorough of an analysis of the 5F11 (big brother to the Harvard) as he's done with the 5E3. I think it would be a great candidate given that it's a fixed bias example and uses a bias-wiggle tremolo (they went a different direction with the Tremolux). As an artifact, it's unique within Fender's inventory.

    Otherwise there's a couple of guys here who have built Harvard's before. What about the original Fender layout isn't clear to you? You could always just grab Mojotone's 5F11 layout diagram and subtract as warranted.

    harvard_5f10_layout.gif

    Tweed-Vibrolux-WD---Bias-Pot.gif
     
  3. mjcyates

    mjcyates Tele-Meister

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    Thanks for the reply. I want to use a different grounding scheme than the original Fender layout. I also want to do the bias pot in lieu of the fixed bias arrangement in the Fender layout. Also it's just really hard for my old eyes to read. Honestly between these two layouts I will probably be fine. Just wondering if anyone had a really good easy to read layout that they have successfully used.
     
  4. JuneauMike

    JuneauMike Friend of Leo's

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    If you search online you can find a larger file size version of the Mojotone layout. Mine was a large 11x17 sheet. Robrob's 5E3 split bus grounding scheme works for this amp too. Mojotone presumes a 10k bias pot, but pretty much everyone will recommend you go with a 50k. Hope that helps.
     
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  5. mjcyates

    mjcyates Tele-Meister

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    It does, the only question that I think I have based on these two layouts is the filament wiring on the 6AT6 preamp tube.
     
  6. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    Only pin 3 is the filament on the 6AT6.
     
  7. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    And I am pretty sure you jumper it over to pin 4 :)
     
    Last edited: Nov 14, 2018
  8. JuneauMike

    JuneauMike Friend of Leo's

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  9. mjcyates

    mjcyates Tele-Meister

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    Thanks guys, much appreciated! Parts should be rolling in soon.
     
  10. JuneauMike

    JuneauMike Friend of Leo's

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    Before you punch that order in, I'd recommend you download DIYLC (its free) and do your own layout. I did that on my last build and I've used the program to layout a build that's still in its planning phase. It was really instructive. The program is really intuitive too, you can get the hang of it by just playing with it. That's the program Rob uses for the layouts you saw on his page.

    I found that when I sat with the schematic and the old tyme Fender layout and recreated it on the page that I could kinda climb inside the circuit. It helped me in deciding what parts to purchase before the build and helped in some layout challenges that presented themselves. FWIW.
     
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  11. rjtwangs

    rjtwangs Tele-Afflicted Silver Supporter

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    I love tweed Harvard's, Michael Clark just built me his version called the Webster. It's a wonderful amp. Sounds big and loud with an original Jensen P10Q from 1959. Maybe send Michael an email and see if he can help you.

    http://www.clarkamplification.com/webster.html

    RJ
     
  12. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    Yes, but it’s a 6V tune not a 12v. So that’s why I think you jumper the two pins with one 6.3v filament wire. Heck I should know off the top of my head as I’ve put together a few of these now. :) lemme go look at one.
     
  13. JuneauMike

    JuneauMike Friend of Leo's

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    The 12AT6 is a 12v and 6AT6 is 6v. Just looking at the Fender layout diagram and the more modern 5F11 diagram I would have thought you'd elevate the ground and run a heater wire to each pin.

    But yeah, I defer to your experience definitely. I'm out of my depth on most things amp-related. Ha.
     
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  14. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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  15. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    Sorry Juneau Mike. :). You are correct!!
     
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  16. mjcyates

    mjcyates Tele-Meister

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    "Before you punch that order in, I'd recommend you download DIYLC (its free) and do your own layout. I did that on my last build and I've used the program to layout a build that's still in its planning phase."

    Once again, thanks for the replies. I have done enough research to know the components that I want, except for the transformers. I have seen a few posts to point me in the right direction for those. I am actually doing my own layout in visio. I will post it here when I think it is somewhat complete so you guys can tell me if I got it right or not :).
     
  17. JuneauMike

    JuneauMike Friend of Leo's

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    The blind squirrel gets a nut ...
     
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  18. Stratandtele

    Stratandtele Tele-Meister

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    I built the Mojotone 5f11, basically a Harvard with tremolo. It's a great sounding amp. It is a much "cleaner" amp than a 5e3 deluxe or Princeton. It stays clean up to about 6 on the volume then gets only moderately dirty at full volume. Have fun with your build, I'll be watching. Please post pics as you go along.
     
  19. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    What PT did you buy? The Hammond one I used last time was spot on for voltages. 290CAX.
     
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  20. Viejo

    Viejo Tele-Holic

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