"Gareth Magennis" wrote in message ...



"Cursitor Doom" wrote in message ...

Hi all,

I have an Audiolab 8000 amplifier I picked up at a boot sale and would
like to establish what it's capable of, since subjectively the power
output seems a bit on the low side when driving recommended speaker loads.
Anyway, ideally I'd like to use an 8 ohm 100W power resistor as a dummy
load for each channel and then measure the p-p voltage output across it
on a scope with the amp turned right up. Trouble is, I don't have such a
resistor and was wondering if there's any suitable substitute? I recall
someone somewhere using a car headlamp bulb but I doubt they come as 8
ohm units so some sort of elaborate series/parallel combo of lamps would
be necessary to get that value. Has anyone a better idea?
cheers, CD.




Here's another idea:
Get a reel of this -
http://uk.farnell.com/pro-power/ecw0...25m/dp/1230984

By my calculations it will have a resistance of 4.25 ohms. (117m of the
125m length gets you 4 ohms)
Although it is only rated at 0.8A, I reckon you could extend that massively
by unravelling it all and laying it in a large container of water.
You could even have a flow of water through the container to keep the
temperature down.

It would be interesting to find out what power rating this could actually
tolerate.

Or is this a really stupid idea?! (For some reason this amuses me)



Gareth.







Just to extend that idea a little further:

You could probably put a wood former into the chuck of an electric drill,
and quickly and easily make a long coil using this enamelled copper wire.
You could then partition the coil into several smaller ones without cutting
the wire, and suspend them vertically in a container of water.

Quick back of a fag packet calculations:
Suppose you made a long coil 10cm diameter. You would then suspend 0.5m
lengths vertically in the container, so the windings are spaced 5mm apart on
average.
This gives 100 turns at 31.4cm per turn giving 31.4 meters of wire per coil.

So you would need 4 of these series coils from the 117m of wire required to
get a 4 ohm load.


Now, how many Watts could this contraption handle?



Gareth.