CLASS A AMPLIFIERS

Atmasphere, thank you for your explanation. Although I'm no EE I think I understand what you're getting at. I will have to try a suitably high quality and high power SS amp on my panels to see what it does to the treble.

Yada, currently I am using the Odysseys; their midrange is simply excellent, and they have good dynamics, but (as mentioned) they are not the equal of my previous ribbon speakers in the topmost treble. (Overall a much more musical experience; it's the midrange that counts the most!)

If an amp is rated 200watts @ 8 oms and 400 watts @ 4 oms what is the 3oms rating.
The reason I ask is Im trying to match components with Thiel CS 2.4 speakers I just purchased.
Thanks,
Dave

It depends on the amp. In theory if it is a solid state amp we would hope to see 600 Watts @ 3 Ohms if the amp is rated as 200 watts @ 8 Ohms. This generally doesn't apply to tube amps. Not all (in fact few) amps are capable of this kind of power delivery. Don't assume an amp is capable of this.

Charlot

To keep it simple - the benefit of the Class A amplifier is in it's sonic product! This is one of those things that is ineffable and must simply be heard and compared.
I have been listening to Class A amplification since the late 1990's and have no complaints. In 2005, I built a 1 watt SET that currently supplies my sonic entertainment.

Keep in mind that transistors as well as tubes can run in Class A. In fact, transistors in Class A come pretty close to doing tube-like stuff sonically.

Hope this helps.

Studio1

Spear11,

It depends on the amplifier; the regulation of its voltage and its current output capacity.

We've been discussing amps that "double down" - those that will double their power
if the load impedance is halved. If we let V be the RMS voltage; then we can use
equations for power that look like the DC equations - but the use of the RMS values
make them applicable for AC power.

For a voltage source, the power P = V^2 / R; or P*R = V^2 = a constant if V is strictly
regulated. If the amp is rated at 200 watts at 8 ohms, then V^2 = 1600 volt^2. For
your 3 ohm speakers, P * (3 ohms) = 1600 volt^2.

Therefore, P = 533.3 watts.

Now this also presupposes that the amp has the current reserves to fulfill this. For
200 watts at 8 ohms; the current is given by P=(I^2)R; so that the current I = 5 amps.
For 533.3 watts at 3 ohms, the current will be 13.33 amps.

IF [ big IF ] the amp has the current reservers to output 13.3 amps, and the voltage is regulated to be the same irrespective of load impedance; then this hypothetical amp
can put 533.3 watts into the 3 ohm load.

Dr. Gregory Greenman
Physicist