12V power supplies?

[space_ryerson]

My day job is in IT, and today we were doing some cleaning. I came across a box of many power supplies/wall warts in various voltages that is slated for disposal. I picked out the 9V DC wall warts, but I came across around 15 12V DC power supplies, ranging from 600ma to about 2a. I know I can use one to build a valvecaster, but which ones are worth keeping? What are some other projects that use 12V? I live in a tiny New York apartment, so my wife probably wouldn't enjoy me coming home with a whole bunch of these

[flintstoned]

Put a volt meter on em and see what they really put out, I salvaged some "12v" supplies from my job and they all read 17v so I'm saving em for my 18v builds

[maarten]

Main concern is the current the tube needs for the heater filament; probably this will be 300 mA (12AX7 or some comparable tube). Now for the the rest of the circuit the requirement is much lower, so 600 mA will be sufficient. Should you want to experiment with two tubes, then 600 mA wont do. Personally I would go for the largest one, so you can combine the Valvecaster with some small transistor power amp on the same powersupply. But maybe that is not your ambition....
Maarten

[rustypinto]

I work for an IT company and i get all kinds of 12, 24, and 48VDC supplies of all kinds. They're usually high current, SMPS and they've worked great with pedals and tubes for me. The SMPS types are usually rated to +/- 5-10% of their rated output voltage. The ones i've tested with a DC load are right on the money too. Only drawback is the majority of them are center positive, so if you're willing to adopt that you're good to go. If not they're great for bench use.

[space_ryerson]

Thanks, good to know!

[composition4]

Put a volt meter on em and see what they really put out, I salvaged some "12v" supplies from my job and they all read 17v so I'm saving em for my 18v builds

Just be careful with this one.  The reason they read 17v is because you are measuring them without a load on them (only the tiny load of your multimeter on resistance mode)

As soon as you put a decent load on them such as a valve heater, the voltage will drop down nearer to 12v, depending on how big the load is and the transformer in the PSU.  Sounds like the PSU is unregulated.

Jonathan