SOUND!

I got my new Firefly amp working. I am too lazy to post another photo.

The sound is very good, although a little dark. I think a pedal will fix that. You can brighten the sound by adding a capacitor; I don’t know if that will make it warmer or just tinny.

The amp has a boost channel. I don’t really understand the circuit, but I assume this just recycles the amplified sound, using the main circuit as a preamp. Anyway, it’s pretty danged loud. But with the boost off, you can turn the main circuit gain up all the way without getting loud. The sound is nice and coarse, so it sounds like the tubes are actually working, but the plaster doesn’t fall off the walls of the house, as it would if I turned up any of my other amps.

I have advice for anyone who builds one of these using a PCB. First of all, why use a PCB? It’s easy and small, but the amp will still be small if you use an ordinary circuit board, and you’ll save forty bucks or something.

Second, don’t use the onboard stuff, like the pots and jack and switches. There are places to mount these items directly to the PCB. This forces you to drill very precise mounting holes in the cabinet. It all has to line up. That’s stupid. Just run wires to the PCB and mount this junk wherever you want.

When I finished getting this thing into working condition, I had no cabinet to plug it into. I found a solution. I borrowed the jack from the Telecaster I’m building, and I wired it to the Weber speaker I’m going to use in the cabinet. I stuck the speaker on the couch and plugged it in. Works great. Not elegant, but I was in a hurry.

It turns out the tubes have to be mashed pretty hard to get them into the sockets. One of mine fell out. Also, the little screw-tightened wire connectors on the PCB are hard to get right. The wires tend to fall out, which is bad.

I attached the top using only glue, and so far, it has worked. They tell me a good glue joint is stronger than the wood around it, so why not put it to the test? If it breaks, I’ll put it back together with screws and supports.

I have to figure out how to paint it. I think I’ll just blast it with leftover truck bed paint. It will be very tough, and I won’t have to blow twenty bucks on a vinyl covering.

It needs knobs. If I can’t find anything around here, I may machine a couple out of aluminum. That would be fast, and it would look good, and I could rub it in the noses of all the non-mechanical people who already think I’m superhuman because I can solder resistors onto a board.

Now all I need is a tiny cabinet for super portability. The speaker I bought is a 12″ job, and it sounds good, but for convenience, it would be good to have something really small, like a car speaker. And dang it, I KNEW I’d need the old Dodge and Ford speakers I threw out when I upgraded vehicle stereos. DANG it. I just realized that. Maybe I still have the Dodges. I wonder how sensitive that speaker is. And how do you check the impedance? Can you just stick an ohmmeter on it? I might have to stick a resistor in there somewhere.

This is beyond cool. Now I have to make the big cabinet, the little cabinet, and a Murder One clone, which is a sub-one-watt amp using submini tubes, whatever they are. It’s the size of a pedal. I may even try to make a PCB for it. You can do that, if you’re a big enough nerd. I already have the PCB and photo paper, plus free circuit design software.

Man, what is happening to me? I’m turning into My Favorite Martian.

I’ll try to record this thing eventually.