4ohm

[karsk]

How much power do is obtainable with amp15 and 4 ohm with lower power supply??

[mikechw]

The mosfet can handle 6.2A at 100 degrees.

If power is calculated by Current x Current x Resistance.
6.2A x 6.2A x 4 ohm = 153.76W

I am not sure if we should use the RMS current which is 6.2A / sqrt 2 = 4.38
4.38Arms x 4.38Arms x 4 ohm = 76.88Wrms ??

[karsk]

i dont think thats correct because of the limitation of the supply to +35-35v...

[mikechw]

35V is enough for 4 ohm load...

35V / 4ohm = 8.75A... which exceeds the max current that mosfet can handle...

[mikechw]

At 25 degrees, the mosfet can handle 8.7A...

So when I stated that 6.2A is the max... I am being conservative..

[wadoka]

I've run 46vdc and 4 ohms speakers very loud, no problems, bugger all heat coming from the fets either!
Not exactly the most scientific statement I will admit , at first I was quite concerned about using low impedance speakers on my Amp15 but I've come to the conclusion that its a tough little amplifier and powers anything I've tried.

I believe V-bro did a torture test of the Amp15 with low impedance speakers and high rail voltage with no problems.

[mikechw]

I ran my AMP15 at 43VDC into 6 ohm speakers.

When the AMP is at idle, it power usage is around 30W. (Measured by a power meter at the mains)

When the AMP is playing very loud, it measures around 180W.

So I assume it is drawing at least 180W-30W= 150W...by 2 speakers.

[V-bro]

quote:Originally posted by mikechw

I ran my AMP15 at 43VDC into 6 ohm speakers.

When the AMP is at idle, it power usage is around 30W. (Measured by a power meter at the mains)

When the AMP is playing very loud, it measures around 180W.

So I assume it is drawing at least 180W-30W= 150W...by 2 speakers.

Then it will deliver much higher peak power, even though much of that is smoothed out by the bulk caps. Nevertheless it'll deliver quite impressive transient peaks...

I have indeed tortured one of the prototype amps with 4ohm speakers and went up to max rail voltage on my lab supply. Left it playing out real loud for a while and nothing got damaged...

At first I imagined it delivered much more than 100W/ch until Jan published the amp to be "just" that power....

------X-max. can be several meters on any driver, too bad it can be done only once...------