The AD Audio Cannonball is a 50 watt Class A amplifier that uses two KT150 valves and runs without negative feedback. AD Audio builds the Cannonballs under licence from Oddwatt Audio.
The Cannonball’s generate a thunderous 45 watts of pure class “A” power @ less than 2% THD and have a maximum output of 55 watts. Class “A” is set by the use of a constant current source in the output stage.This novel design provides the best bass response of any valve amplifier I have heard.
The Cannonballs use the 6SL7 driver tubes along with a regulated power supply. The amplifiers deliver outstanding power and exhibit superior sonic qualities delivering clear, deep and very articulate mids and highs with a huge sound stage with incredible performance and control being heard in the low frequencies with a sub audio response which is flat to 10HZ. Bias is electronically set so does not require adjustment. There is a balance pot for balancing the output tubes which is a simple operation using a supplied meter and test points on the rear panel once every six months or so. The Cannonballs are capable of driving difficult load loud speakers such as electrostatics that exhibit a highly capacitive load like Martin Logan Vistas as well as more conventional speaker systems with ease.
Rated Power output 45 watts RMS
– Distortion below 0.5% through half power, 1% at full power*
– Frequency Response 8HZ to 20 KHZ +0/-1db at any rated power*
– Signal to noise better than 85 db
– Tubes TUNG SOL KT150, Tung Sol 6SL7GT
* Typically below 0.3%
A feedback switch is provided, allowing no negative feedback or 3db. I don’t know anyone who uses these amplifiers with the feedback switched on though! Alternatively, most purchasers have preferred this configured as a triode /pentode mode switch.
Most contemporary amplifiers seem to be involved in a horse power race. Bigger is better seems to be the mantra. Often sound quality in the lower power levels is sacrificed to get greater output.These amplifiers provide superb quality sound at all listening levels and avoid duplicated pairs of output tubes which in my opinion never produce the same sonic results.
The amplifiers are hand-built using silver wire in the signal path, Kiwame carbon film resistors, Solen and LeClanche capacitors, gold/teflon input sockets,and Audio note silver-plated speaker binding posts.
Cost is currently £3,500 per pair of mono blocks.