Western Electric is taking orders for the 91E single-ended (SE) integrated amplifier, inspired by the iconic 91A.
In the distant past, the 91A was used in early Hollywood films. After resuming production of 300B triode tubes at its state-of-the-art Rossville Works, Western Electric is now launching a new SE delivering over 20W per channel – a first for a 300B in a 21st century design.
Western Electric Type 91E is built with a patented circuit that more than doubles the power of the 300B compared to conventional 7-8W. The amplifier received a replaceable transformer block – the standard 8 ohm transformer block can be replaced with an optional 4 ohm version. A matched pair of 300Bs, included with each amplifier, are front and center mounted. The microprocessors automatically adjust the bias current of the 300V pair each time the amplifier is turned on.
The 91E uses a parallel power topology that sends half the AC current to the 300B plate (anode), modulating the quiescent current. As a result, half of the power dissipated occurs in the lamp, resulting in more power output. A stepped logarithmic attenuator is used to simulate the response of human hearing. It is assembled from discrete resistors in a ladder configuration, providing logarithmic output attenuation.
The dimmable color LCD displays the selected input, attenuator level and volume meter. The display also shows settings that can be adjusted using the supplied remote control.
