Whilst many companies have produced 300B based amplifiers, we wanted to produce a 300B which made use of the exquisite midrange which the 300B is famed for, whilst improving the frequency extremes which are usually curtailed by most current designs. After paying careful attention to the topology, driver circuit and the output transformer, we are finally happy we have a real world 300B Class A amplifier, which we have christened the Astro Black 8.
The Astro Black 8 delivers 8W/ch and therefore requires a high sensitivity loudspeaker. This amplifier comes equipped with four line level inputs and a single XLR balanced input. The preamplifier stage is a direct derivative of the circuit used in our acclaimed Pure Black 101 preamplifier. In this design we use the rare and underrated 101D as a rectifier whilst two pairs of 6SN7 valves are used for signal amplification, before being fed to the 300B output valve in each channel. Internally the amplifier makes use of the highest quality components, including Jensen paper in oil capacitors and stepped attenuator using 24 pairs of close tolerance resistors, minimising the number of components the signal must travel through.
Like all the products in the Astro Black range, the chassis is finished in high gloss black with only three controls on the front panel, with a power switch on the left hand side, a volume control in the centre and the input selector on the right. The top plate holds the 300B valves on the outer edges of the chassis, inside those are a pair of 6SN7 valves and a 101D in the centre. The amplifier is supplied with a full cage should you wish to cover the valves during operation. The rear of the chassis holds three transformers, a HT transformer, a power transformer and an output transformer.
The back panel is home to 4 pairs of RCA phono inputs and a single pair of XLR balanced inputs. There are three five way binding posts per channel, allowing you to select between 8 ohm and 4 ohm output taps to optimise the sound in your system with power input via a high quality IEC power inlet, allowing you to optionally use an aftermarket IEC power cord.
Specifications :
Output power: 2 x 8 W en classe A
Tubes: 300B x 2, 6SN7 x 4, 101D x 1
Frequency response: 20 Hz ~ 20 kHz
Montage sans contre-réaction
Input Impedance: 250 k Ù
Output Impedance: 4 ohms, 8 ohms
Input sensitivity: 480 mV
Ratio S/N: = 90 dB
Harmonic Distortion: 1 %
Dimensions (mm): 440 (l) x 185 (h) x 380 (p) mm
Weight: 28 kg |
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