John Sayers' Recording Studio Design Forum

Hi all this is my first post and i'll try to keep it simple.

How do you go about working out what the equipment in your studio is going to draw?

e.g my monitors are 63w max so I would just add these sorts of figures together and come up with a total?

Most of my stuff has a figure on the back in Watts but some are given as VA, this is the same is it not?

And then there are others that have nothing written or maybe have a voltage and amperage figure. Is there some other method I should use to calculate or test power out put or current draw ?

Guitar amps are often called 100 w or 50 w amps or what have you, and I have two 5000w amps for the P.A is this a close enough figure to tell me what they will
draw?

For equipment that gives no information on the case how do you go about working it out?

Anyway thats probably more than enough questions for now. I'm pretty comfortable with the acoustics side of things but the electrical part is a whole new can of worms.

Thanks for any help.

Scott Hansen
Belltone Recording Studios

What you mostly need to add up would be your total amperage of the equipment. Most equipment and/or power supplies will give an amperage rating. Either amps, Voltage Amps (VA) or millivolt amps (MVA).

Most equipment in a studio with the exception of consoles, tape machines, guitar amps, etc. usually don't pull much amperage. Example, most current outboard gear are probably rated in mVa. Where as power supplies for a console can range (depending on the voltage you're running...this makes a huge difference in power draw...eg: my console when run on 110v pulls a 7 amp load per supply, but when running 220v, it pulls half the amperage at 3.5 amps.)

Here's some formula's:

Watts = Volts x Amps

Amps = Watts / Volts

Volts = Watts / Amps

Thanks Aaron,
It's just the electrician-who wired up these industrial units we are building in-gave me a fright when he said that they only had a very small power supply to them. He wasn't too sure when I said i had couple of thousand watt amps to run (maybe he heard thousand amps and freaked out) Ive got another electrician coming over tomorrow so I'll see what he says.
Thanks again