High Current / Low Current / No Current ??????

Sheesh. If an amp is making 100 watts into 4 ohms it is the exact same amount of current whether the amp is tube or transistor. Ohm's law (and the Power formula which derives from it) says so: 100W = Current squared times Resistance.

The speaker is 4 ohms so:

100W=5 squared x 4 ohms. IOW the current is 5 amps at 100 watts.

The idea that its a good thing that the amp power doubles as the load is cut in half is a bit of mythology. What this suggests is that you won't always have flat frequency response in your room with every amplifier (notwithstanding the effects of the room itself).

A further note: in the past I've seen amps that claim that they can make 80 amps or some such. What exactly are they try to say? Giving the benefit of the doubt, let's use a one ohm load for the amp. This gives 1600 watts! 'Current' ratings like this are actually a rating of how much current is available when you short the power supply for 10ms. We do that easily with our tube amps...

The fact of the matter is that in general Magnaplanars sound better with tube amps then they do with transistors. They don't always play as loud, but they do sound better. 'High current' amplifiers (IOW: transistors) are about volume rather then finesse.

Try the the moscode 600 and forget about the theories. there is one for sale on this cite.

The way Atma-sphere describe the use of "high current" is incorrect. High Current amplifiers enjoy the ability of being able to return a driver to its resting point better than a low current amplifier.

A quick way to describe this is high current amplifiers are like having stiffer shocks, when the woofer is moved by an input it does not come to rest immediately because its suspension is compliant. A high current amplifier when faced with the electrmechanical energy created by a woofer will present a higher resistence to the moving woofer stopping it sooner. Low current amplifiers cannot "control" the driver with the same authority and that is why many tube amplifiers (low current) have a boomy bass, they can't stop the driver.

The OTL actually does a better job that a transformered tube amp, but 30 amps control the driver like 80 amps.

Magneplanars benefit a great deal in the bass by getting control from a "high current amplifier" because maggies need help stopping or coming to rest. That's why you'll see Bryston 7B's on maggies at shows. Helps control the panels.

Damping factor is an old myth that has many advocates. That is what D_edwards is talking about above.

The simple fact of the matter is that damping factor has marginal effect on most drivers. Yet, we hear differences- what are they about?? What is happening is that in a 'low damping factor' amplifier (IOW 'low current') as the impedance of the load gets closer to that of the output impedance of the amplifier, the amplifier will make more distortion. It is important to understand that this type of distortion occurs without the amp clipping.

As audiophiles we have developed words for this type of (harmonic) distortion. A moderate amount of distortion is described as 'bloom' or 'warmth', excessive amounts are described as 'muddy' as in 'muddy bass' or as in 'loss of control'.

What is important here is that the driver is not contributing to this, these are artifacts of the amplifier.

Magnaplanars have always sounded their best with tubes. The reason that transistors get used with Maggies is usually power, not control. It is quite expensive to develop power with tubes and Magnaplanars (particularly older ones), require a lot of power to get high volumes as their magnets are located on only one side of the driver.