80v power supply

As I noted in another note, Im getting into servo motors! My first
problem is that the motors Ive found are 80v, 4Amp motors. I have not
been able to find an 80 v supply.

So, it seems to me that since the power line is 120 v I shuld be able to
do a simple power supply. Suppose I took a light dimmer- the common
triac variety, and hooked its output to a bridge rectifier, then to a
filtetr cap. I should be able to adjust the dimer to the right value to
hold the output voltage to 80v.

I understand the issues of not haivng an isolation transformer here, but
I can work with that, Will the basic triac work to give me a lower
output voltage, or will it be to badly regulated?

Any suggestion for a simple regulator that will work here?

ron