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Browsing through electronics at a Goodwill yesterday, an interesting amplifier caught my eye. I know good gear when I see it, so I took a closer look. It's weight suggested a linear power supply rather than a switcher. Looking at the back, I saw that all eight inputs are modular bays that can be filled with an array of different cards. It had two three pin XLRs and a couple of RCAs. At first I thought it was a stage amp for a small band and that I could definitely make my $12.99 back and then some. I was confused by the outputs though; they were labeled 25 volts and 70 volts.

After getting it home, I learned that it is actually more of a business-wide soundsystem amp for a constant voltage speaker system. (Article here: https://en.wikipedia.org/wiki/Constant-voltage_speaker_system)

I'd never heard of these and they are fascinating. Rather than running loudspeakers directly from the amp's output transistors, the audio goes to a step-up transformer and then to a step-down transformer integral to each speaker. The advantages are that you get higher fidelity on smaller wire for the same reason that power companies transmit at high voltages to minimize losses; it provides equivalent signal at much lower currents. The transformer also allows connecting an arbitrary number of speakers up to the current limit of the supply without worrying about overstressing the output transistors. This is the sort of thing that might run a soundsystem in a grocery store or restaurant for instance.

I have no use for one (not that I had a use for a gig amp for a band either) and plan to try to resell it. It won't be as salable as I thought, but I still think I can make money on it.

Dee was kind enough to come pick up me from the store since I was heading to their place anyway and wasn't sure about how to load it on my bike. They're sweet.

Anybody want an amp for their store?

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I am so tired today... I have not been getting enough sleep.

Selling Things!

I have some things to sell. If you want more info please let me know!

*Vintage '80s Japanese 10 speed road bike. Lugged steel frame and pretty paint job. Drop bars and friction shifters. : $150
*10 band stereo graphic equalizer with frequency analyzer: $40
*7 band stereo graphic equalizer: $20
*30 watt constant voltage amplifier compatible with 25 and 70 volt speakers with 8 modular input bays: $50

--The next two have a possible buyer, but if it doesn't work out, they'll be available
*Marantz 2220 stereo receiver. 20 watts per channel, integral phono preamp. Not original speaker jacks, and the tuning signal strength meter doesn't work. May also need FM alignment for better reception. $150
*Technics belt drive turntable with relatively new cartridge/stylus. $40

I need to make room!

I Guess I Still Kind Of Know How to Do This

Last night, I'd planned to make a working computer out of the one that Wendy gave me and parts from my brother's old computer. Instead, I spent half an hour or so, on and off, looking for my binder full of utility discs, including my Windows install media. No luck. Eventually, as I was about to give up, it occurred to me that maybe I should just put Linux on it. Nothing Windows-only needs to run on it. Dee, want to help me figure out Linux some time?

The last time I installed a new OS was probably three or four years ago when I built a new computer for doing GIS work. I finally had to move away from XP not because I wanted to play the latest new games or something, but because the newest version of MS Office wouldn't run on XP anymore and I had too many compatibility problems getting papers to professors. I can't help but laugh at being forced to build a new machine just to run a productivity suite.

I then spent an hour-plus setting up hardware for the install. I looked all over for an exra VGA cable, then found that neither of the video cards in the two computers suppport VGA. I looked all over for a DVI cable and couldn't find one. I made a giant mess by spreading hardware all around the floor and disconnecting the DVI cable from one of my desktop's monitors and computer, but then found that one video card's jack was DVI-A (I don't think I've ever actually seen one of those before!) and the DVI-D cable wouldn't connect. I just wanted to see the system specs of each computer, so I figured I'd just swap the video card between the two and write down the BIOS info. But the DVI-D capable card requires a supplementary power connector from the power supply that the the other computer's PS doesn't have. I though briefly about swapping the power supplies, but quickly dismissed that idea. I guess I won't be using that computer's motherboard or video card for this project!

Meanwhile, my desktop was downloading a Linux flavor that was recommended for newbies - Mint - and creating a bootable thumb drive out of it. Once that was done and I had a working box together for it, I set up the BIOS to allow me to boot from a USB stick, plugged in the drive, and powered up. And the system booted to Windows from my brother's old drive. "I specifically told you not to do that," I commented, since I talk to computers while I work on them.

I rebooted and found that the BIOS no longer had a boot from USB option. Where'd it go? I unplugged the drive and rebooted. Not there. I scratched my head. I plugged the drive into a rear slot instead of the front panel and rebooted and there was the option again! This time I could boot from the drive. And by this time it was past 9 o' clock, so I left everything a mess by my desk to come back to when I have more time. I'm not sure when that will be at this point, but I'll get to it eventually.

Part of me misses doing this stuff for fun. Maybe it's been long enough since I was supporting computers professionally that it's kind of novel again. I'm still glad I'm out of that career though!