Computer Power supply add-on from 12AX7
The Constant Current module will work on its own if that is all you need.
For computer PSU scales, a few IRFZ44 or so (commonly found in automotive apps, e.g., car amps, 12-120V inverters), or something in an IRFP, like an IRFP064 or so (same idea, but bigger package (TO-247) --> more dissipation (about 100W, vs. 50W for a TO-220 like the IRFZ44, et al) in a single unit). The IRF3703, is along the same lines.
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