New Amp Build - from design to flipping the switch

Discussion in 'Shock Brother's DIY Amps' started by corliss1, Mar 31, 2015.

  1. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Hew TDPRI crew!!!

    I really love reading through the build threads on here so I figured I'd do one of my own. I'm going to attempt to document the *entire* process of building an amp from start to finish. No really, everything. At least I'm gonna give it a shot.

    This is a fairly typical 15-18 watt thing. EL84, blah blah. You know the drill. I'm gonna show how I do everything - chassis, cabinet, turret board - so you can see the wrong way to do it. It'll be fun, it's gonna take a while but I swear it'll get done eventually.

    The first thing I do is make sure this crazy thing is actually gonna work...so I build it on my epic test chassis of death. Why is it called the epic test chassis of death? No idea - but everything sounds better when you add "of death." Try it - caramel sundae of death. See?

    Anyway, test chassis build

    [​IMG]

    If your prototypes don't have paper separating things and masking tape holding down wires, you don't know tone :twisted:

    After we have the proof of concept and know (well, hope/pray) that the amp will actually work I lay out the circuit board on graph paper.

    [​IMG]

    many failed attempts...

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    and a group shot for fun

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    Once the final version is done I draw up one more to use to drill the circuit board template which looks like this

    [​IMG]

    Then grab some MDF from the scrap pile that was pretty darn close to the right size:

    [​IMG]

    and cut it down

    [​IMG]

    Once that is ready we can attach the drill template:

    [​IMG]

    [​IMG]

    and we end up with something like this:

    [​IMG]

    We'll use that template to drill the circuit boards.

    So, follow along on this epic journey. I'm thinking it's probably gonna be June-July ish before I get one of these up and running so there's plenty of time. Stay tuned!
     
  2. andyfromdenver

    andyfromdenver Friend of Leo's

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    Best wishes "of death" to you.

    wait, there's one instance that doesn't work :)

    but seriously, best wishes.

    is there a schematic link/ hi res pic?
     
  3. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    I had a secret bet with myself you'd be the first reply :D

    I don't have a schematic yet - drawing one up is on my to-do list of death...wait..............
     
  4. TelekineticBoss

    TelekineticBoss Tele-Holic

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    Looks promising! I'm sure you'll have fun with it.
     
  5. andyfromdenver

    andyfromdenver Friend of Leo's

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    :eek: I can appreciate the hand drawn DIY and humor
     
  6. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    See, I'm deeply torn. As a full-time computer dork I sit and look at these things all day and I could probably come up with a way to do a nice schematic. But the other part of me says the old Fender layouts and schematics were art. The hand-drawn tubes, French curves for the wiring on the layouts - really killer stuff. Compare it to anything else of the time and it's just miles ahead, in my opinion.

    Anyone have a good schematic making tool for the computer?
     
  7. joeford

    joeford Friend of Leo's

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    this is the first thread i've ever subscribed to... and exactly what i need, a really broken down step by step. you better finish it... you don't want my first subscribed thread to be a dud!

    good luck on the build... i'm expecting a good education and lots of humor (no pressure) :D:twisted:
     
  8. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Thanks Joeford!
     
  9. tresspassor

    tresspassor Tele-Meister

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  10. muchxs

    muchxs Doctor of Teleocity

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    You think they used French curves?!

    I took "mechanical drawing" back when the final step was inking the drawing. Draw it in 2H and 4H pencil then ink it by hand.

    Nuthin' like droppin' a big ink blob on your pristine drawing. :rolleyes:

    ..or havin' capillary action from the circle template suck up the ink. :rolleyes:

    I'm tryin' to remember the super- duper India ink art pens. We passed the factory the other night on the way down to Telefunken.

    My mom used to sell them to the advertising industry in the late '50s.


    I use the "Nikola Tesla" software. The schematics and layout drawings are all in my head.
     
  11. robrob

    robrob Poster Extraordinaire Ad Free Member

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    trespassor, thanks for the link to the ExpressPCB tube symbols. I have used E PCB for a few headphone related projects but didn't bother with amp stuff because the lack of tube symbols.

    Rob
     
  12. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Thanks for that - I'm gonna try and use that for the schematic. The extra symbols you provided are also helpful :D

    I'm totally guessing - the lines are so nice I figure they used some not freehand technique.
     
  13. King Fan

    King Fan Friend of Leo's Ad Free Member

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    MuchXS said:

    I'm tryin' to remember the super- duper India ink art pens. We passed the factory the other night on the way down to Telefunken.

    Was it Koh-i-noor Raipidograph? Amazing things tho with a tendency to dry/clog...
     
  14. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    So I got a few things in the mail today. The first thing was a gift from the laser engraving fairy. I got back plates:

    [​IMG]

    and faceplates:

    [​IMG]

    If you ever need stuff like this I seriously can't recommend Joe at amplates.com high enough - awesome work, quick turnaround time, and great communication.

    The chassis and circuit board fairy also showed up:

    [​IMG]

    Now, I'm gonna do three of these guys but I'm gonna focus on one and make sure that works how I plan (it never does). That way I don't butcher three chassis and three boards before I realize there is an issue.

    So, the first step in making this a step closer to an amp is to attach a board to the circuit board template:

    [​IMG]

    Call on our friend Mr. 3/32 drill bit:

    [​IMG]

    and 64 pulls of the drill press later we end up with this:

    [​IMG]

    Now to add the turrets. I made a little adapter plate to hold the turret staking tool to my drill press, which looks like this:

    [​IMG]

    and here it is attached so you get the idea

    [​IMG]

    If you've never worked with turrets before here's the deal: they are a tiny, hollow piece of pre-tinned metal. You put a turret in the hole you just drilled in the circuit board and press down hard. This flares out the bottom of the turret, permanently gripping it to the board. Although the next few pictures aren't from this particular project it shows you the process nicely:

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    [​IMG]

    Here's what a real nice one looks like:

    [​IMG]

    Now, for the love, before you start adding turrets do yourself a favor and mark the mounting holes. That way you don't get done and realize you put turrets in the mounting hole holes as well. I mean, I'm not saying I've done that personally....but...................ya know...

    After 60 slightly more forceful pulls of the drill press, you get this:

    [​IMG]

    Next step will be a chassis template and we'll actually drill some metal.
     
  15. tresspassor

    tresspassor Tele-Meister

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    You think putting turrets in the mounting holes is bad? I once installed about 20 turrets before I realized that I was putting them in backwards. Now I always write "backside" on the backside of the board.
     
  16. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    oooooooooh - yeah, that could get awkward!
     
  17. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    So everyone was all "you need a pretty layout so we can see it." FINE

    Here's how I went about that.

    We started with the original drawing you guys all know and love:

    [​IMG]

    And then I scanned that into my favorite editing software:

    [​IMG]

    I *love* paint.net. It's the name of the software, not the website. If you want a good artsy tool without the learning curve of GIMP/Photoshop I can't recommend it highly enough. Go check it out. http://www.getpaint.net/index.html

    After the image was imported I drew the basic shapes:

    [​IMG]

    added some components

    [​IMG]

    Here's what the whole thing looks like with all the layers visible:

    [​IMG]

    and here's the final product

    [​IMG]

    I just need to go through that and compare it to my original drawing and the prototype to make sure everything is actually right before I start wiring this thing up.
     
  18. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Since I'm gonna make more than one of these I make a chassis drill template. First I cut down some MDF to the size of the chassis using my incredibly accurate duct tape table saw:

    [​IMG]

    Don't you judge...

    Then get it to the final length...

    [​IMG]

    You can see how this is gonna go with this guy:

    [​IMG]

    At this point we start the planning. I'm not afraid to be wrong even though wrong costs money, but the planning isn't anything fancy - just moving stuff around to see how it's gonna fit.

    Like I've mentioned earlier, I plan to make three of these guys to start but I only do one complete build first so I can see all the screw ups................I mean, improvements.........that need to happen.

    Planning

    [​IMG]

    More planning

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    This is also the time to make a router template for the power transformer cutout. It starts with something like this:

    [​IMG]

    goes over to the spindle sander, which I'm so happy I finally got one:

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    and ends up like this:

    [​IMG]

    [​IMG]

    Then drill the mounting holes:

    [​IMG]

    My theory is that if it fits nicely in a 1/2" piece of plywood it'll be great in the .09" chassis :D

    I also went ahead and drilled all the faceplates - even though I'm only making one amp I know the faceplates will all be the same. I can't really screw this part up....I think...

    Start with these three guys:

    [​IMG]

    Line em up sorta closeish

    [​IMG]

    Tape them in place - you *really* don't want anything to slip during this process. Partly for hole accuracy, partly for personal safety of spinning sharp metal acting like a lawn mower blade. Don't ask me how I know...

    [​IMG]

    Clamp it, then drill everything with 3/8" bit:

    [​IMG]

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    drill out that pilot light and switch with 31/64" bit:

    [​IMG]

    and then I just finish up the pilot light hole by hand. If you've ever tried to drill one of these out you know there not a lot of room on that lip that holds it to the chassis so you better get it right. My ancient hand files do this in about 2 minutes so it's really not as bad as it seems.

    [​IMG]

    test fit

    [​IMG]

    Once that's all done we can get serious with the chassis layout:

    [​IMG]

    I think I'm happy with this for now - still gotta route the transformer hole (which I hope to get to tomorrow when the weather is decent) but this should work. Maybe. We'll see.......

    [​IMG]
     
  19. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Chassis drilling time, with the adventures of bird boy and squirrel bro!!!

    No really...

    So, it was nice out today and I got outside once it got around 48ish degrees. The sun on the back porch helps out a lot.

    SO - time to make a chassis. I started out by drilling some countersink holes in the power transformer routing template:

    [​IMG]

    I then clamped up the master template to the routing template and drilled my pilot hole so I could start the router:

    [​IMG]

    After some noise...

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    Now we're ready to start thinking about the actual chassis. I put the MDF template inside the chassis and marked another router starter hole:

    [​IMG]

    and then drilled that out:

    [​IMG]

    Now for this part, the bolts are just serving as an alignment tool. They aren't tightened, but they are just there to keep things more or less in the correct spot while I drill all the chassis holes

    [​IMG]

    After some more noise:

    [​IMG]

    and here's the finished product:

    [​IMG]

    Now, I flip the template over so I'm looking at the back. This way I can use the template on the outside of the chassis.

    [​IMG]

    Drill some more countersinks:

    [​IMG]

    At this point I had a visit from bird boy. I'm no animal specialist but I'm assuming red = cardinal

    [​IMG]

    That's about 12 feet or so from where I was working on the porch. Didn't seem to mind.

    Now we attach the template firmly to the chassis since we're gonna route it out:

    [​IMG]

    Here's what it looks like from the back now:

    [​IMG]

    add some more noise...

    [​IMG]

    The aftermath...

    [​IMG]

    Now enter squirrel bro. Squirrel bro was way less afraid than the bird. He was within 10 feet, making eye contact multiple times while stealing from my neighbor's bird feeders. He hung out through 4 holes drilled and one routing session.

    [​IMG]

    Next up is the IEC jack. Only way to do this is with a template, and I should really make a better/more accurate one a some point, but this works just fine:

    [​IMG]

    Got the pilot holes:

    [​IMG]

    Routie Routie:

    [​IMG]

    Next I came through and did all the tube socket holes with 3/8" bit:

    [​IMG]

    After that I checked to make sure the transformer cutout was gonna work:

    [​IMG]

    Really happy with how that turned out.

    I'm gonna have 4/8/16 ohm outputs on these so I setup my rear panel and drilled that with 3/8"

    [​IMG]

    Here's everything to this point:

    [​IMG]

    Only thing I wasn't sure about was the grommets:

    [​IMG]

    Turns out these guys live in 1/2" holes nicely:

    [​IMG]

    Only thing left to do on the chassis is to hit the tubes with a socket punch and then drill the tube socket mounting holes. Once that's done I can start and bolt this thing together. It seems to go together pretty quick at that point. Thanks for following along!
     
  20. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Turns out I did have enough time today to punch the chassis holes. If you're not familiar with a chassis punch they look like this:

    [​IMG]

    You put that inside the 3/8" hole (although, pro tip, I find going one size over that keep the scrap piece from getting stuck, so I always drill a 25/64ths for that smidge of extra clearance) and then tighten it down. It cuts a perfect circle that isn't sharp and fits tube sockets exactly. They come in all sorts of sizes.

    Here's what it looks like tightened down inside the chassis:

    [​IMG]

    Get out your breaker bar or other implement of destruction:

    [​IMG]

    After a few turns you get a nice hole and the entire punch assembly will just fall out.

    Here's what the scrap looks like - there's 4 12AX7s and 1 GZ34.

    [​IMG]

    Here is what they look like when they're done:

    [​IMG]

    Went around and marked the mounting holes:

    [​IMG]

    And got those drilled as well:

    [​IMG]

    Now, if I'm good, or lucky enough, this should be all the metal work necessary. I think I made sure all the holes are gonna work with number 8 hardware, #6 on the tube sockets, so I should be alright. Sometimes you have to incorporate a little slop to get things fit and aligned right, but we'll see how it goes once I start putting things together.

    Next up is getting everything mounted!
     
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