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Rob Robinette's SLO Nakid build, but with 6L6s

Discussion in 'Shock Brother's DIY Amps' started by zeppelinofled69, Oct 27, 2020.

  1. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Got the idea in my head that I needed one of these while I was looking over the layout and schematic on Robs site.

    Decided I've been really into the 6L6 thing lately, so I got an old Baldwin organ power transformer and ordered a bassman OT with multiple taps on the secondary.

    I didn't have a large choke like the one in the layout, but this 4Hy one from a bassman should work? I'm trying to repurpose as much from my stash as possible to save on cost, but if this choke is too small I can order another... chassis real estate is starting to get scarce though.
     

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  2. robrob

    robrob Poster Extraordinaire Ad Free Member

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    The choke will "probably" work. Other than the output transformer change for 6L6, I would also recommend bumping the screen resistors up to 5 watts.
     
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  3. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Thank you Robrob!

    I have another choke on hand, but I don't actually have any idea what it's ratings are. It's quite large and came out of a military Tube regulated bench supply made by Sylvania (Type B-323A). I once had a schematic to it, but can't find it right now. It ran a 5AR4 rectifier, a pair of 6Y6Gs, 6SJ7 and one or 2 others.

    Any idea if this would be any better than the one I am planning on using now?
     

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  4. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Got the output transformer in the mail today, so I mounted it and drilled the holes for the wires to come through the chassis.

    I also swapped out the chokes and squeezed the bigger one on to the chassis. We will see how it looks once it all comes together.

    My order with weber still hasn't shipped yet, but once that happens, I'll have everything to get this together.
     

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  5. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    My orders have been a little wonky and parts are not coming in as expected, but I am making progress as stuff slowly rolls in.

    What I have managed to get done:

    Mains power section wired up
    Ran Heaters
    All socket mounted resistors are mounted
    Finished main board component mounting and soldering
    Pot locations are selected and drilled out
    Speaker impedance selector is in and wired up with the output jack.

    Up next is to wire up the main board to the pots and tube sockets. Just waiting on some more turrets so I can finish making the bias and B+ power supply boards.
     

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  6. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Main board to tube sockets and pots is done. Amp is mostly there except the power supply.
     

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  7. dan40

    dan40 Friend of Leo's

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    Looking forward to hearing how it sounds when you're done!
     
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  8. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Well, The faceplate is real ugly right now until I find a good way to cover the extra holes. Thinking I may get some 1/16" plexiglass and spray paint the back of it black but not sure if this'll work yet.

    As for the sound... It's easily the best amp distortion I have heard by far. Super articulate but still thick with tons of note bloom.

    I will get a decent video of the sound up at some point, but right now I have a few tweaks to make. Voltage to the preamp tubes is a little higher than I like with B+3 being at about 410V DC. Thinking of changing the 6k dropping resistor that I planned for to a 8-10k. Just need to mess with it to find the sweet spot.
     

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  9. SKEsq

    SKEsq TDPRI Member Silver Supporter

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    I kinda dig the labels as is.
     
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  10. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Oh, don't get me wrong, I love dymo labels, and will probably continue to use them. The issue I have is the old crappy faceplate that was on here was glued on and I have yet to find a solvent that will take the old adhesive off.

    What I will probably end up doing is making a cheap faceplate like I mentioned above and then re-label everything with dymo again.

    Either way, the more time I spend with the amp, the cooler it gets for me. This is my first amp with any real kind of gain... Everything else I have built or owned has been fender amps for those sparkling cleans, and I usually just get dirt from pedals.
     
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  11. Tom Kamphuys

    Tom Kamphuys Tele-Holic

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    I like your wiring. It is almost as if half of it is left out. Maybe it is the wire size. Maybe because it is layed out nicely (solid core?). Maybe my grounding scheme is causing an excess of wires. Dunno.
     
  12. tele_savales

    tele_savales Tele-Holic Platinum Supporter

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    Have you tried Goof Off? Not Goo Gone. It should make very short work of any adhesive residue, just be super careful with it as it will melt no metal items.
     
  13. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    To be honest, I have to give a lot of the credit to Robrob here, as he is the one who translated the schematic to the board layout. With the board layout sorted, it made it easy for me to keep things neat.

    And yes, I do use solid core wherever I can. I think this stuff is 22AWG teflon coated wire that I got for a good price from a supplier on ebay.


    I have not, but may take a trip up to the hardware store to see if they have a bottle. Thanks for the tip!
     
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  14. SKEsq

    SKEsq TDPRI Member Silver Supporter

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    I plan to build this one eventually. I built the JCM800 6V6 not that long ago - that's been fun to mess around with.
     
  15. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Nice looking build Zeppelin. Congrats on getting it up and running.
     
  16. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Thanks a lot Robrob. I certainly appreciate you making the circuit available for use.

    This one is going to a friend of mine, but I may do another for myself in a low wattage version just for kicks.

    I can see this being a stellar practice and recording setup in the 1ish watt version, so that may be the next project.
     
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  17. robrob

    robrob Poster Extraordinaire Ad Free Member

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  18. zeppelinofled69

    zeppelinofled69 Tele-Meister

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    Nice! Thanks Robrob.

    As I mentioned in the official SLO Nakid thread, I did change the screen resistors to 1k ohm 7 watt units and hung them off the side of the sockets.

    I plan to try and get some recordings of the amp done over the thanksgiving break. Once I get em done I will upload them to somewhere and post back here.
     
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  19. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Soldano used 470 ohm 1 watt screen resistors even in the SLO-100 100watt. 1 watt is enough as long as you don't use EL34s. They will usually blow and save damage if the screen shorts.
     
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