There are a number of audio power-amplifier modules that enable a DIYer (do-it-yourself-er) to quickly build some surprisingly high-quality audio power-amplifiers. A number of Class-D switching amplifiers are quite capable of addressing the unique and sometimes demanding load characteristics of the various Martin-Logan electrostatic loudspeakers.
A very popular option is available in the series of UcD modules from Hypex (
http://www.hypex.nl/). These high-power/high-current units are amazingly efficient in terms of AC power consumption, so all you really have to do is bolt the credit-card-size modules to almost any chassis and you've easily satisfied the heatsinking requirements. The Hypex UcD modules are the basis for the very popular series of power amplifiers from Channel Island Audio; these commercial implementations have received a number of positive reviews in the mainstream audio press.
My personal favorite from a sonic standpoint is the ZapPulze series of Class-D power-amplifier modules from LC Audio (
http://www.lcaudio.com/); these credit-card-size units seem to have been designed explicitly for the audiophile marketplace. Among other features, the ZapPulse modules can be easily configured for both balanced-line and single-ended inputs. But the feature that really sets the ZapPulse modules apart from the competition is the ability to to drive the modules from an external clock source; the Class-D operations are then synchronized between the channels and you can nearly double the operational frequency of the modules (thereby significantly moving the switching artifacts away from the audio band).
--Mullard EL34
