[Czilla9000]

Hello DUIers....errrr.......I mean DIYers

Lets us say there is an amplifier that can do 50 watts into 8 ohms...........how do I calculate say, what that amp would put into 2 ohms, or 12 ohms, or 300 ohms, or 60 ohms, or.......well you get my drift.

 

[peranders]

Check page 48 here (page 47 according to the page itself)
http://www.elfa.se/se/fakta.pdf

This is the Ohm's law circle

 

[kevin gilmore]

Ohm's law is only the theoretical calculation.

A 50 watt amp at 8 ohms might put out 100 at 4 ohms
and 200 at 2 ohms, but only if the power supply and
output transistors are capable of that.

It is likely that a 50 watt amp at 8 ohms might do at
least 25 watts into 16 ohms, depending on whether
it is voltage limited or not.

 

[D-EJ915]

sometimes amps are weird (especially digital ones) and their specific components make the weirdness possible, but some car amps put out 300W into 4 ohms and 400W into 2 ohms, don't ask me why, but they do somehow, it must be the limited power avaliable to them, but beware what your amp is putting out is probably less than what you think.

 

[Sovkiller]

Be carefull some amps are not stable under 2 ohms loads, and for 300ohms an amp that give you 50w/8ohms, I think will be 0, or near that.....

 

[D-EJ915]

Yes, that is one thing you have to look out for, I don't think the amp will catch fire or anything like that, but it might spark or something. Most Car Audio amplifiers are stable under 2 Ohm loads, but that's only the better ones at that, home audio amps are more sensitive to impedance and sound the best at their rated nom. impedence, but my NX10 did put out a good signal into the right channel into a 2 ohm load, a feature hard to come by in this day and age, but I never tried it on both at once, well...I don't have enough speakers to do that