Author: bob

My Marshall amp has been sitting unused for a long time because it doesn’t make any noise. Recently I’ve been wanting to get it going again so that I can play electric guitar from my couch instead of walking all the way downstairs (i.e. ten feet). Any old amp will do this task as I can use my POD for effects. But I have the Marshall so why not put it to use? Incidentally, I can just connect the speakers directly to the POD’s headphone amp, but that’s no fun.

Vacuum tubes are notorious for being flakey, so I figured a new set of tubes might make it work again. I ordered a new set, plugged em in, no go. The power tubes heat up but the preamp tubes do nothing. That’s about the extent of my expertise on amplifier repair, so the only other thing I can do is open it up and look for cold solder joints or blown fuses. Alas, I found nothing obvious when I did this.

Working on any high power AC gear is dangerous. In fact, today while discussing my broken amp with a coworker, I said that despite my many hours logged in EE labs in school, I was not at all comfortable working on it myself. Perhaps I should have listened to me.

I was smart enough to unplug the amp, and careful enough to keep a hand in a pocket. But still, I was sloppy when putting it back together and managed to discharge a high voltage cap with my fingers. Holy hell that hurts! I dropped back a couple of feet and let out a loud scream. Youch. I will not be doing that again anytime soon. Luckily, I don’t have any permanent damage: I got a tiny electrical burn on my middle finger (that probably would be worse if I didn’t already have a half-inch callus on it from playing guitar). And I earned a healthy fear of high powered electronics.

So, people of the internet, don’t do what Donny Don’t does. Discharge those caps!

You pretty much have to buy vacuum tubes from the third world or eastern bloc these days since they aren’t much in demand over here. The ones I bought were all Sovteks. I love the Soviet iconography on the box:

Saturday, I deconstructed a broken CD-ROM to make a toy. This is essentially a so-called “symet,” which is the simplest device in the BEAM robotics world. Usually, they are made with solar cells and the accompanying logic, but as I don’t have any of those, I just used a AA battery. One battery, a motor pilfered from the aforementioned CD player, and some vacuum tubes glued on for balance (they serve no electrical purpose; I just had them sitting around and they look cool). Pretty simple but more fun than a box of Transformers. Possibly.

This is what the inside of a 1st gen CD-ROM looks like:

This is what the inside of my MP3 player looks like:

I spent a few hours yesterday doing the house-wiring thing. Again. I’m running cable for HDTV from my attic to my living room. Therefore I have little pink bits of fiberglass insulation everywhere. I have the cable running the whole distance to the TV but I had to stop short of getting it actually into the living room. It appears that I will need to reopen the hole in the wall from last time to drill a new hole through the stud to let the cable up from the crawl space. And then patch and repaint. Why am I doing this again?

In the district the other day I saw a jeep with spinners on the spare. Awesome, dude! I bet that guy has 20″ rims if-you-know-what-I-mean.

As a consumer of all types of liquids sold by heartless multinationals, I discovered this week that a plastic Evian bottle cap mates perfectly with a Coke bottle cap to make a little enclosure. It occurred to me immediately, nerd that I am, that this would make a good project box for any really small electronics project. Not having any such projects in mind, I decided I would make something simple and useless, and what’s more useless than a flashing LED?

The circuit for a blinking light is pretty straightforward – it’s just a timer chip with an LED on the output. Except for the batteries (I used two 3V watch batteries taped together), I happened to have all the parts on hand: a 555 Timer chip (from a red box that I never built), 3 resistors, a capacitor, an LED, wires and some perfboard. This site has more info if you want to build your own. I just picked my own combination of resistors and cap that had a frequency around 2 Hz, then proceeded to do one of the worst soldering jobs ever, then cut up the perfboard so that it fits nice and snug inside the bottle cap. Now, I think it is time to listen to some Floyd.

A long time ago, I lost my way. And by “way” I mean “the F-connector die set for my racheting crimper.” That thing is impossible to find. I’m trying to locate it because I just got a large new aerial TV antenna so that I can get more hi-def channels (for a mere $25 – don’t waste your money on the $100 ones at BB or CC). I plan to mount the monstrousity of aluminum in my attic and connect it via RG-6 running through the same path in the walls that my cat-5 cables take. This will be a bit more challenging the second time around since the holes in the walls cut for that purpose are now all sealed up. Anyway, last night, unable to make a 100′ cable without the crimper, I assembled the antenna in my living room and connected it via some short coax I had around, and the results are fantastic. Before, I could barely receive FOX and get nothing else; now I get all the networks, mHz, and PBS in glorious digital picture and 5.1 sound. Hooray for the electromagnetic spectrum! WB still doesn’t come in, as if I watch that anyway. Maybe this weekend I’ll get it all setup in mythtv so that when I record, say, the mind-enhancing television show 24, mythtv uses the HD card instead of cable.

(Kill your TV.)