Author: DaveMDaveM
Date: Jul 20, 2008 15:20
"dave" 127.0.0.1> wrote in message
news:rvb784hr7086opqfqf0d4qpth9mm38u4f5@4ax.com...> Looking for ideas here... I'd like test a PA amplifier rated at 300
> watts into 4 ohms.
> Any ideas as what I could use for an dummy load - apart from some
> actual speakers (drivers) that is! I'd also like the load to be as
> resistive as possible and not inductive as the drivers would be.
> As I don't have a 4 ohm 300 watt resistor in the spares box - any
> ideas what could be used as a "subsitute"?
You will probably get advice to use a string of light bulbs for this purpose,
but I have to advise caution there. The resistance of an incandescent bulb is
very low when cold, and rises significantly when current is applied. It's not
easily predicted and can lead to blowing your amp. The bulbs can easily look
like a short to the amp when cold and kill it before you get started with a
test.
You should look for something that has less resistance change when heated.
Thinking of the heating element from a toaster, electric frying pan, electric
space heater or other household appliance. Of course, you'll have to measure
and combine appliances as appropriate to get the right value.
| 
