I didn't think to order a power supply in advance, doh. The strongest wallwart I can find in my house I'm not using is 12V 2A. I saw burnin mention earlier in thread that a 12V 2.5A would be okay to run a single bitburner board. Would a 12V 2A work safely? I'm running a single 20 chip XX board.
No, it's not enough for BTB. Non-overclocked BTB should take about 50W (on 12V that about 4 A), overclocked to 450 MHz takes about 105 W (that's 8.75 A on 12V).