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Original Message
Apples and oranges
Posted by Lew on January 13, 2005 at 08:24:24:
The "need" for an OTL amplifier is not related to a need for high power. In fact, OTL amps are in general relatively less efficient than transformer-coupled tube amps in converting the power available from an output tube into power that can drive a speaker. The beauty of an OTL amplifier is in the elimination of the output transformer entirely, which leads to lower distortion, wider bandwidth, greater transparency, etc. For your speakers (112db efficiency!!!) you want a low power amplifier with a very high signal-to-noise ratio. But you have not mentioned the nominal impedance rating of your speakers. If your speakers are rated at 8 ohms impedance or higher, and if the impedance curve is relatively flat with respect to frequency (real world impedance or resistance of a speaker varies with frequency), then you might find bliss with an OTL type. If your speakers are rated less than 8 ohms OR if there is a serious dip in impedance at critical frequencies (ultra-high frequencies don't count), then you might look elsewhere or consider an OTL in conjunction with an impedance matching device, such as a Zero autoformer.