Leema-acoustics TUCANA II Handbook - Tucana II
Contrary to another common misconception, ‘timing’ cannot be compromised.
The square wave performance of an amplifier is the ultimate timing test. A look at the square wave performance of a Tucana II is
testament to the time domain performance of the design. If multiple devices did cause errors in the time domain, the resultant
square wave would be significantly degraded. This is simply not the case. Apart from the mild rounding of the corners caused by
amplifier input bandwidth filtering, the square wave response is virtually perfect and has no overshoot or ringing.
On the subject of ringing, if the amplifier is tested in to a load including a capacitive element, inaccurately trying to simulate an
electrostatic loudspeaker, ringing will be observed at the output in response to transient signals. In fact, this ringing is not caused by
the amplifier. It is simply the resonant combination of the amplifier output inductor and load capacitance. No notice should be
taken of any test reports including the level and makeup of this ringing, as the results are totally dependant upon load type and
applied stimuli.
The power amplifiers incorporate no output stage protection circuits except for power supply fuses. Leema designers feel that even
quite complicated protection schemes remain somewhat audible. If the output stage fails due to a short circuit or component
failure, the fuses offer safety protection. An auto-detect and disconnect circuit protects the loudspeakers from damage.
The resulting amplifier has the following characteristics:
Low noise
Very low distortion, typically much better than leading class A designs
High output current delivery
Low output impedance
Fast and detailed, yet untiring audio presentation
Very robust and reliable
Topology
TUCANA II
13
Tucana II 1KHz Square