how do i make a 50V power supply?

Look at www.hypex.nl.

could you just hook up like two 24Volt transformers in parellel with the AC line and then hook up the outputs in series to get 48 volts or would that be ceating to much current? i dont want to have to get a torodial transformer

I presume you want + and - 50 volts DC for an amplifier project. If so, you don't want a transformer that puts out 50 volts AC. When you rectify and filter the transformer output the DC voltage will be near the peak of the AC waveform, which would be 70 volts. In practice there will be some loss so the DC will be a bit less, but still far from 50 volts.

Your best bet is to get a packaged ready-to-go DC power supply, such as those available from hypex. Many other manufacturers also offer power supplies. You need to know how many amps it must supply as well as the voltages.

Can you use a variac (variable transformer)and monitor the output.

I assume that you want 50VDC? How much current needs to be supplied? Does the voltage need to be regulated? Will the current demand be constant or will it vary? What about sonics? Poor choices made in designing a PS can destroy the sonics of the gear it's used in. Without more information no one is going to be able to help you. Besides voltage and current requirements and the possible need for regulation there are issues such as: noise (how much ripple will the following circuits tolerate), transformer ringing, switching noise generated by silicon rectifiers, etc. Also, many if not most audio circuits, analog output stages in particular, include the PS in the AC signal current loop (a capacitor acts like a short to an AC signal). The filter cap in the PS will most often be in the signal path and affect the sound of an amp. It would help if you'd indicate what type of equipment this PS is going into.