Jag tyckte det kunde vara intressant att höra vad Roger Sanders anser att det krävs av en förstärkare som skall driva Maggisar.
Roger har förutom en ESL amp även utvecklat en förstärkare till Magneplanarer.
http://www.sanderssoundsystems.com/products/amplifiers/magtech-amp
"Your questions involve the basic physics of electricity. So I will respond with the scientific facts. I will try to write this in layman's terms so that it is both understandable and entertaining.
I will respond to your questions and comments in the order I find them in your text. The first issue you mention is damping factor.
The damping factor is mainly determined by the ratio of the impedances of the devices involved. Specifically, the damping factor is the ratio between the output impedance of the amplifier and the input impedance of the speaker.
As an aside, impedance is the same as the resistance. But resistance is the term used in DC circuits, while impedance is used when discussing AC circuits. The reason for the difference is that the impedance often varies with frequency, while DC has no frequency, so the resistance will be always be the same. But when doing calculations, impedance and resistance are used interchangeably.
You are probably aware that tube amplifiers usually use output transformer to match the inherent high impedance of tubes to the low impedance of speakers. The output transformer will have taps at specific impedances, typically 8 and 4 ohms.
So if you have an 8 ohm speaker, you will use the 8 ohm tap on the output transformer of a tube amp. Since the impedances are the same, the ratio between them will be 1:1. Therefore a tube amp will typically have a damping factor of just one, which is very poor.
By comparison, solid state amps inherently have very low output impedance. So they do not need output transformers to reduce their impedance enough to drive loudspeakers.
For example, the output impedance of my Magtech amplifier is 0.01 ohms. When driving an 8 ohm loudspeaker, its impedance ratio will be .01:8, which is a damping factor of 800.
The damping factor is also increased (improved) by the use of global negative feedback. Tube amps often have less feedback than SS amps, so once again, a SS amp will have a higher damping factor on this basis as well.
In short, you have things reversed when you say that tube amps have a better damping factor than SS amps. The opposite is true. SS amps have much better damping factors than tube amps. This is why tube amps often have rather "floppy" and poorly-controlled bass while the bass from SS amps is generally "tighter", "cleaner", and clearer.
As for power, voltage, and current, understand that magnetic speakers (like Magnepan builds) operate on current. It is current that produces the magnetic field around the wires that produces the force needed to move the speaker's diaphragm. So the sole purpose of the amplifier is to drive current through the speaker. Current is everything when powering Maggies.
Ohm's Law dictates that voltage is required to push current through the speaker. Understand that voltage is the pressure that pushes electrons through the resistance of the speaker (measured in ohms). Current is the actual flow of electrons and it is measured in Amperes (usually simply shortened to "amps). Power is the product of volts times amps and is measured in watts.
Therefore, the power of an amplifier will be determined by the voltage it can apply to the speaker. This assumes that the amplifier can deliver the current required for a particular voltage. So the amplifier's power supply voltage is critical to determining the power it can deliver. That power supply must also be able to supply sufficient current to produce the power needed at that voltage.
Ohm's Law says that one volt will drive one amp through one ohm. So if an amplifier can produce say 20 volts into a 4 ohm Maggie, it will drive 5 amps through it. The power produced will be the product of the volts times the amps, which in this case will be 100 watts.
Both tube and transistor amps will have to produce the same voltage and current to produce that 100 watts. So it doesn't really matter which type you use as long as they can both produce the same voltage and current.
Since the current delivered to the speaker is a function of the voltage applied to it, it doesn't matter how much current an amp can deliver beyond the amount of current demanded by the voltage. In the example above, 5 amps of current was produced by the voltage. That is all the current that can or will flow through the speaker.
So it wouldn't matter if the amp can deliver 5 amps, 50 amps, or 500 amps, since it would flow 5 amps and that's all. Any ability of an amp to deliver more current than needed will never be used. Therefore the term "high current" amps is a meaningless audiophile term.
What is far more important than all this audiophile talk about damping factor and high current amps is simply power. It is power that an amplifier must deliver to a speaker to make them play dynamically, loudly, and clearly. Without adequate power, an amplifier will be clipping, distorting, and generally performing very poorly.
It is amazing how much power is required to reproduce dynamic music at the realistically loud levels most audiophiles prefer. It is easy to measure the power loudspeakers require. When you do so, you will see that Maggies require a minimum of 1,000 watts per channel.
When viewed in this way, you can easily see that most audiophiles are using underpowered amplifiers and are therefore getting poor sound. Your main goal when selecting an amplifier should be getting sufficient power.
Sufficient power can be produced using either tubes or transistors. But it is far easier and less expensive to get high power levels using transistors than tubes. Do you know any tube amplifier that can produce 1,000 watts?
By comparison, my stereo Magtech will deliver more than 1,000 watts/channel into a Maggie speaker. The monoblock version of the Magtech will deliver 3,000 watts into one. These power levels will really make a Maggie sing. No tube amp is available that can match such power levels.
I designed the Magtech specifically at the request of Maggie owners, most of whom were frustrated with the power limitations of conventional amplifiers. To really do a good job, I found that the amp needed a regulated power supply. Since no conventional amplifier has a regulated power supply, I designed a unique one that is so efficient that it runs cold. The result is the Magtech amplifier."
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