Tremendous Lunch - Model Fun - A 5w single ended amp based on the Kalamazoo Model 1

So a friend at work let me borrow his 60's Kalamazoo Model 1. It's a surprisingly good sounding low wattage Class A amp, and sports a really decent sounding CTS 10" speaker. Since I'm doing a lot of living room recording, I thought it would make a good project, and would be a fun low volume alternative to my 100 watt Fender Super Six. I think these amps can be purchased in the used market for under $300. Minus tools, I believe a spent just about the same building the head.

The amp that inspired the build.

 Power transformer is a Hammond 269EX, Output transformer is a 10w 125DSE

Started the project cutting the most annoying hole.

Slowly pealing back the protective covering as I mount stuff.

Grommets and mounting hardware via Harbor Freight.

Stepped drill bit for the tube holes.

I got this ridiculously heavy duty switch. The earth shakes when you click it. 10,000 years from now when the earth in nothing but a nuclear wasteland, frog people will salvage this switch to repair their margarita makers.

Overly thick ground bus bent. I figured if I got something huge, it would offer a bit more rigidity for the point to point wiring, but it ended up being a bit of a pain. It barely fits through the 1/4" jacks solder lugs, and it came untinned. I had to clean, sand, flux, and then crank up my Hakko to 800°F to tin it. Next time, I'll do something a bit thinner, and pre-tinned. Also, It will sort of be a nightmare if I need to replace a jack. But hey, that's a problem for future-me. Screw that guy.

Here's the one ground point to the chassis. Everything else is completely isolated. The original is hardly a work of art and used a ground scheme known as the "nearest point in a storm" approach.

Output transformer wiring. A cooler guy would've used a switch. 

Main power wired.

Heater wiring done.

First resistor in. I'm completely winging it on the layout. 

The resistor from the input jack is on the wrong pin in this picture. Also, the wire this should probably be shielded. The amp is extremely quiet and the run is extremely short, so I haven't fixed it. I'll get to it later.

This is what some folks call "True Point to Point Wiring" to make people using turret board feel bad.

More parts going in. In a perfect world, the electrolytic power filtering capacitor's ground should be isolated and a bit closer to the ground point, but they make nice little points to solder stuff to. If I placed the filtering caps a bit more proper, I probably would've had to use a couple more terminal strips. The amp turned out quiet in the end, so who cares. I'D DO IT AGAIN. FIGHT ME.

And yes, I accidentally wired the volume pot is wired backwards.

Other than fixing a couple little mistakes, the wiring is complete at this point. I left the tone circuit out of this build, and it ended up sound just fine without one. I left space to add a tonestack in the future. I'm thinking baxandall.

I was using some used tubes that I borrowed from work, but once everything was working properly, I switched to a Tungsol 12AX7, and a JJ EL84.

Hot glued the heater wiring and the electrolytic caps in place.

Yes, the volume pot is still backwards. I also don't like the shielded wire I used. I've fixed both.

Alright! Part 2: The Cab

I've been fixing tube amps full time for a couple years now so the amp build went pretty easy. But this is my first real woodworking project. I was pretty proud going into the project. I thought to my self  "I can make accurate measurements, this will be easy." With the extremely limited space, and limited tools, I made a bunch of mistakes, wasted quite a bit of wood, and learned a lot.

I tried at first to do the whole thing finger jointed by hand. I don't want to talk about it.

I bought this Ryobi RTS10G table saw from Home Depot for $130. This was probably a mistake. The miter is completely worthless, it wobbles a full 3 degrees in the miter slot. I built a little miter sled (pictured) to account for the weirdness. The miter slots are not standard, so even if you had a nice miter siting around, you can't use it. The fence doesn't lock down square, and the blade isn't square to the table horizontally, so you have to offset the fence to account for that.

I live in an apartment, and my work space is a tiny sun room. I also have to carry the saw down 2 flights of stairs to store it when not in use, so it's not like I could get a real saw, anyway.

It's $130. What can you expect? It's pretty sturdy, safe, and has plenty of power, I'm not exactly offended by it.

I jointed and planed the pieces by hand, and after several failed attempts, I ended up with some wood cut to length square enough to use.

Butt jointed the sides. After messing so much stuff up, I was too scared to try any fancy joinery. It would be sturdy enough with all the other pieces added.

I bought a rather nice Dewalt DWP611 router with a plunge and fixed base off Craigslist for $75. It's absolutely fantastic. I used decently cheap Ryobi router bits. It worked lovely.

Test fitting the hardware.

I added a bit of trim to the front and cut the front panel from cabinet grade plywood.

Cut the back panel out,

I got all the hardware off a broken practice amp from work.

Sanded to 1000 grit or so.

First coat of stain.

1 zillion coats of stain.

4 Coats of wipe on poly.

Cabinet is done. I sort of wish I wouldn't have stained it. It was really hard to get an even dark finish over the pine, and the stain brought out every little imperfection. It's just an amp, and it looks good enough.

Overall, I give it a C.