For over 80 years this fabulous valve has reigned supreme in the field of audio. Designed by RCA with only slide rules, no computers at that time! Never bettered* and still in production it is an absolute for those that like a big warm detailed sound. The 845s Achilles heel is the demands it makes on the amplifier built around it. Others make the mistake of making the amplifier to complex, resulting in a loss of fine detail and strangling its ability to sing. It needs a huge power supply to breathe properly. Our massive power and unique LDT output transformers allow the 845 to be as refined or as brutal as you wish. David Shaw has kept his design simple and big. With Vaughn Williams it will ascend to breathe taking heights, with Hendrix it will give you greasy hot buttered riffs like you never heard before. In our experience the 845 has been a very reliable long lived performer. At 66kg (145lbs pr) they are not for everyone!
When we first released the MB845s in the UK they were greeted with great acclaim by the Hi Fi press and customers, for power and value, but above all their unique sound quality. They have become a reference valve amplifier for Hi Fi World magazine.
For some people only a large triode valve like the 845 can give the golden warm tone which is so pleasing, with its feeling of air and space and sense of realism.
Our MB845 MK I has truly become a legend in the UK, but Hi Fi fans were soon asking if there was more we could do to improve the performance. With the MB845 MKIIm, we have used all our expertise to create our ultimate amplifier. Surprisingly from such big amplifiers is how well they perform at low powers. Their agility and detailed texture of strings and vocals is quite astounding. Modern recordings demand low noise amplifiers, the MB845s will give you an “ink black silence”
The MB845 MK IIm features upgrades and improvements including a built in bias meter which greatly simplifies bias checking/adjustment, keeping your amplifier in peak performance. Previously you had to pay attention to numbers on the meter. Now if the pointer is on the black mark, it’s correct. Very easy!
Specifications and Features
(Specifications subject to change, errors & omissions excepted. Gen 30/06/12)
*The 845 is designed specifically for audio use. It not a transmitter valve, unlike the 811 and 805, its grid cannot be driven positive making it easier to drive and more linear.