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.
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.
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.
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...
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.
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:
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....
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?
Comments
Classic nitro has ether in it so there's a benefit.
I like how the lacquer darkened the mahogany and made the hickory grain more pronounced.
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.
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...