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My 6G3 Brown Deluxe Build

Discussion in 'Shock Brother's DIY Amps' started by flyswatter, Jan 11, 2019.

  1. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Here's the amp I completed over the holidays, a replica of an early 1960s brown Deluxe 6G3 amp. I've built tweed Deluxes in the past and have repaired/ restored a few blonde and brown-era original Fenders in recent years, plus repaired a nice 65 blackface Deluxe a few months ago, so it felt like the right time to do a 6G3 build.

    I'll post a few photos of the finished amp, then come back and post up some of the play-by-play pictures of the build. I encountered a few troubleshooting issues along the way, all of which were eventually solved, so I'll mention some of those in case others encounter them in the future.

    BTW: In case you're wondering, I make my own eyelet boards, tolexed cabinets, and machine the chassis. The chassis was provided blank by a custom maker and the face plate for the amp was provided by the friend who commissioned it (it appears to be a Mojotone plate). My starting point was the original 6G3 schematic. I'd encourage anyone building an amp to get to know the schematic and to work the build out on paper before you start cutting and drilling.

    6G3_amp01.jpg
    6G3_amp02.jpg
    6G3_amp07.jpg
    6G3_chassis01.jpg
     
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  2. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Some photos of the build process.

    First thing I do is draw up a layout to scale on 11x17 graph paper. I do one drawing for the components, then a transparency with the wiring laid over the top.

    This might seem like a lot of hassle when one can simply download a readymade layout online, but it makes the build easier when you have a scale layout to measure from and can plan out all the component placement and wire lengths in advance. I think of this as "building the amp on paper first" and it helps me to anticipate problems and avoid mistakes with the actual build.

    20180917_133826.jpg

    20180917_133746.jpg

    BTW: There are a few mistakes in these drawings that I fixed later, but this is where I started.
     
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  3. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Circuit board:

    I used blank phenolic board (the stuff that looks pale beige) that I cut to size then paint with heat resistant enamel so it looks better.

    I place a photocopy of the layout over the board to situate the eyelets, then drill and stake the eyelets.

    Once the 3 boards (main circuit board, bias board, doghouse filter cap board) are made, I dry mount all the components and solder them from underneath... the way it was done in a lot of vintage Fenders.

    One really key thing I do is photograph the underside of the board before mounting it in the chassis. Anyone who's ever had to pry up a vintage Fender circuit board to sort out wiring and track down shorts will appreciate why.

    20180922_034441.jpg

    20180922_150601.jpg

    20180922_150145.jpg
     
  4. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Building the chassis:

    Getting the holes drilled exactly to match the face plate saved me a lot of headaches later on. A sixteenth inch misalignment can stop a jack or pot from fitting through.

    Same goes for getting all the main components and boards situated properly. I definitely see the advantages of buying pre-punched chassis for builds, but up here in the Great White North it's simply cost prohibitive.

    20181216_113619.jpg

    20181216_225214.jpg
     
  5. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Wiring up the amp is my favourite part of any build.

    20181222_130815.jpg

    ... which brings me to the first troubleshooting problem. See that extra hole to the right of the V1 socket? I should have waited to drill the holes for the chassis mounting bolts until I'd finished the cabinet. I winged it and drilled them while doing the rest of the chassis... then found later the chassis bolts wouldn't go through and I had to redrill them. Never a problem with a rear mounted chassis like a 5E3! Oh well, lesson learned.
     
  6. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    First power-up = Troubleshoot #2. The amp had a massive 60 Hz ground loop hum that took hours to track down. Checked the wiring against the schematic. Checked it against mine and others' layouts. Everything appeared wired "correctly."

    Here's what the output with the hum looked like on the scope. Ouch!

    20181223_215731.jpg

    Here's what the problem was. I'd grounded all 4 filter caps in the doghouse on a single bus running back to the power supply ground star. Big mistake. Cutting the ground for the last (nearest in the picture) filter cap from there and moving it to the preamp ground bus cured the problem.

    Hum completely gone! The amp sounded quiet as a lamb after that.

    6G3_chassis06.jpg

    [Edited for accuracy]
     
    Last edited: Jan 12, 2019
    Wally likes this.
  7. jsnwhite619

    jsnwhite619 Friend of Leo's Ad Free Member

    Age:
    34
    Sep 10, 2013
    Georgia
    Congratulations! I got the parts and halfway started my 6g3 last spring/early summer and it's just been on the back burner since then. Got the cab framed out and glue together, but still a ways to go. I need to get it finished!
     
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  8. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Cabinet time!

    I used solid pine, dovetailed for the shell. A Baltic birch plywood baffle. The baffle mounts from the front in the traditional way. The speaker is a pretty tight fit in the standard-sized 6G3 cab to clear the transformers, but it all worked out.

    20181230_214846.jpg

    20181231_234325.jpg cab04.jpg


    For tolexing, I used a latex contact cement by LePage -- my favourite product used on many projects. Tolex is rock solid once the glue sets. Regular contact cement can melt many vinyl coverings and I can't stand the fumes. Unfortunately, the latex stuff is twice the cost... but it works for me.

    20181231_171056.jpg

    Finishing touch is the tube chart, made on Word to look like a vintage one... shellac'ed onto the inside of the cabinet.

    6G3_amp11.jpg
     
  9. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Quick video of the finished amp, and we're done!

     
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  10. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec

    Good luck with your build! You'll be happy as a cat when you finally power the finished thing up! I listened to a ton of early ZZ Top for inspiration... apparently Billy used a brownface on a lot of studio recordings.
     
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  11. John How

    John How Tele-Meister

    Age:
    67
    376
    Mar 22, 2016
    Auburn, Ca
    Awesome...I have collected the parts for a 6g3 build after just finishing the 6g2 a couple months ago...now I’m just awaiting the chassis that my metal working son is building for me...I should have it in a week or so...im gonna do it as a 2x10 combo...thanks for sharing your build...I like your MO, working the layout on paper before firing up the soldering iron...I’ll do that as well...I’m going to be using terminal strips so I don’t have to worry about under the board wiring...I found some really nice military surplus terminal strips a few years back and it’s nice being able to see everything while working problems...
     
    Last edited: Jan 11, 2019
    flyswatter likes this.
  12. rjp68

    rjp68 TDPRI Member

    Age:
    50
    51
    Jan 6, 2019
    Central California
    Sounds pretty excellent!! Awesome job..:)
     
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  13. CoyotesGator

    CoyotesGator Tele-Meister

    476
    Jul 12, 2014
    Gulf Coast
    Very Nice!

    Such a great circuit.

    What led you to the Invader and did you try other speakers?
     
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  14. Uncle Daddy

    Uncle Daddy Tele-Holic

    611
    Sep 26, 2015
    Maldon, England
    Does the pulse from the trem creep through on tickover? I had a Vibrolux that I just couldn't cure. I love Brownface trems; Blackface trem always sounds like it needs a vitamin injection.
     
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  15. theprofessor

    theprofessor Friend of Leo's

    Aug 8, 2016
    Chattanooga, TN
    Congratulations, and what a magnificent thread! I love your attention to detail, right down to drawing your own layout on graph paper. Well done! And thanks very much for narrating the build this way for others down the road. Enjoy!
     
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  16. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec
    Thanks. A 2X10 cab will make yours like a brownface Super at lower wattage. Should be a great setup. Brave choice to go true P2P on terminal strips. I hope you'll post pictures of that process; I'll follow for sure.
     
  17. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec

    This particular amp was commissioned by a friend who's an SG/ rock n roll type of guy and he provided the Invader. I have an Invader myself, though, in a Traynor YGM-2 so I approved of the choice. I didn't try other speakers in this particular amp, but 2 yrs ago I restored an original brown Super that got an Eminence Cannabis Rex (good for taming brighter amps as that particular one was, but I think it would have dulled the bright channel on the 6G3).
     
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  18. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec

    Yes, a tiny bit on the bright channel. With the blackface Deluxes that have an optoisolator (roach) it is much easier to cure with an extra coupling cap to ground. Lead dress is important, although I was very careful about lead dress in mine and it still ticked a tiny bit. Keeping a footswitch plugged in cures it; however, there are a couple of other options:

    One simple solution is to install an on/ off switch for the tremolo. Rob Robinette has a diagram for that on his site. https://robrobinette.com/Generic_Tube_Amp_Mods.htm#Tremolo_Cut_Switch_

    I adapted that idea to mine by putting a simple on off switch beside the tremolo jack, which basically acts the same as a footswitch when none is plugged in. It works fine. Tick gone.

    6G3_chassis09b.jpg
     
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  19. flyswatter

    flyswatter Friend of Leo's

    Jan 12, 2013
    Quebec

    Thanks, Professor. I find that drawing things out really helps. It kind of forces one to scrutinize the circuit and layout in way that pays off later when it comes to drilling and mounting components (tellingly, the one element not included on the drawing -- hole positions for chassis mounting bolts -- is where I made my biggest screwup). It also helps with lead dress, knowing just how long a particular piece of wire needs to reach and what else it is liable to rub up against on the way.
     
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  20. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    Flyswatter, beautiful job!! Kudos! One minor observation about the grounding for the filters. That cap that you separated from the others is actually the last cap in the power supply chain and not the first, correct??
    Again....nothing but respect for your work!!!!
     
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