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My new tube preamp build

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Comments

  • Haha  which lacquer are you using?
    Classic nitro has ether in it so there's a benefit.
  • Just shooting Watco clear lacquer from a rattle can but I l'm lovin the results!  Pics tomorrow...
  • Here it is after 3 light coats of gloss.  I might just leave it gloss and not shoot anymore coats:


    I like how the lacquer darkened the mahogany and made the hickory grain more pronounced.
    Bryan@MACTurn2D1PP1NThumperTomkennyk4thtryGowa
  • I glued some hard wood blocks inside so that I could screw down the aluminum top plate and a bottom cover and feet.



    4thtry
  • That is stunning Craig!
  • Nice! And I love the slight relief you put on the bottom too.
  • Looking great Craig!
  • Love the golden brown mahogany shine. It's a wood I have not used in a long time. Shines really well in sunlight!
  • Looks good! I'd leave it gloss. It's not unambitious pin in your eye gloss. It's just nice and glossy.
  • edited December 2017
    Looks great Craig!  Remember, when you're ready to go into production the formula is (Parts + Time) x Six!
  • Oh geez, I might be able to sell one if I only pay myself like $0.25/hr :(
  • I bid 0.26!
  • Hi gents, I just finished machining the aluminum top plate.  This was a 12" x 12" x 0.062" piece of aluminum plate I got from McMaster-Carr for about $12.  For tube power amplifiers, which have bigger and heavier transformers on top, I use thicker 1/8" aluminum plate.  But this little pre-amp project only has a small power transformer up top so the lighter gauge aluminum is more than enough.  This thin aluminum is super easy to cut to size on the table saw with a regular carbide blade.  The big holes for the tube sockets were easily cut with a cheap Harbor Freight step bit.  I just need to sand the top smoother and then I can hit it with some paint.  On the last tube amp project I did I used an automotive spray can paint from Dupli-Color which I really loved!  So I will use it again.  It is:  Engine Enamal with Ceramic DE1651 Cast Coat Iron.


    Silver1omo4thtry
  • I sanded the top plate with 400 grit sand paper then painted it.  Following the instructions on the rattle can I sprayed a light coat, waited 10 minutes, hit it with another light coat, waited another 10 minutes, then sprayed a nice medium/heavy wet coat.

     

  • I took this picture hoping to show that even though it looks like the paint finish has a bunch of texture (over spray, orange peal, on purpose, whatever), it really is VERY smooth.  It's kind of like a show car painted with metal flake.  My camera/phone/skills don't do it justice :(  Anyway, I am very pleased with how it turned out considering I am just a garage DIYer, shooting finishes from off the shelf rattle cans.



  • That looks great! I'll have to look for that paint next time I'm at Lowes. Now the fun part - inhaling  those solder fumes!
  • Hi Tom, look for it at Auto Zone or Advanced Auto.

    Yes, my favorite part is laying out and soldering the point-to-point wires and components.  I used to drill a bunch of holes through the top plate to screw on terminal strips.  For this project I wanted a cleaner looking top plate so I will be using epoxy to attach the needed terminal strips.
  • Looking forward to your listening impressions and BOM.
  • That inlay looks cool and really makes the front panel stand out. 
  • Thanks Bill. That inlay was super easy to do and very cheap. 

    I machined a nice chunky aluminum volume knob at work today.  I will anodize it but not sure if I will leave it clear or dye it black before the nickel/acetate seal.  The front power switch is black so I'm leaning towards black...
  • Super sharp Craig ! I'm curious about the anodizing process.
  • Fantastic progress so far man! Just let me know when you want to do the rotational program with this.  I'm first in line!!!!
    My signature goes here
  • We can work something out Bryan.  I remember how much you enjoyed that little K12G tube amp.  Not sure if you've heard it since I upgraded all the iron and the coupling caps.  It sounds even nicer now and actually has bass response down to the lower 20's.  I listen to it almost every night when I'm at my work bench.
  • Made a little progress, I decided I wanted to use black fasteners exclusively on the top plate for a cleaner look.  I decided to go with black allen head cap screws for everything.


  • Here are the power transformer, tube sockets and tubes installed:
  • Probably the last picture for today...  the aluminum volume knob I turned on the lathe.  I think I will anodize it black to match the power transformer, the power switch, and the allen head cap screws.  I still need to sand it smooth and polish it before anodizing:



    R-Carpenter
  • Craig - that's looking great! Better be careful - once people see how beautiful this is turning out, you're going to start getting requests to build custom projects for people.
  • Thanks Tom, but I would only consider building something like this for a friend I've made at the DIY events, and they would have to do all the tedious wood working....  ;)
    kennyk
  • My Parts Express package showed up today with the Alps 20K pot so I was able to install it and attach the volume knob.  What do you guys think...  clear anodized or black volume knob?



    D1PP1NkennykGowa
  • Here's the rear side...



    D1PP1NkennykGowa
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