The first consumer pair of EXtreme Hurricane MK II Hurricane amplifiers (all V-Cap capacitors) are up and running. I have been asked to post some overall impressions on the new MK II design. At this time, I do not have many hours on them. By the way, the MK II units are much more time consuming to work on and have much less space to work with.
I can say that there have been some substantial improvements in the circuitry of the MK II units. The bias circuitry seems to be much better and more precise, transformers have been improved and the input circuitry has been changed. Balanced inputs are now standard as is a standby switch for the B+ voltage. Nice feature. I like the fact that the transformers and complete power supply are now located in a separate chassis (bottom section of the tower) from the main circuit. This helps keep any potential noise from entering the signal path.
Sonically, in stock form, the MK II amps were dead quiet. Overall, there was a sonic improvement but I did not spend enough time with them to get a really good grasp on all the differences. I simply did not have that much time as I had to get started on the EXtreme mods.
The EXtremes are now in the first stages of a 24 hour burn-in session. 12 hours in triode and then 12 in pentode. They are being feed by a ModWright SWLP with tube rectified power supply and are driving a pair of EXtreme Adagio speakers. This particular pair of Extreme Canes have Gold Bybee Purifiers in the input stage.
Unfortunately, the amps will be gone next Monday on their way to their new home so I will not have a chance to hear them after full break-in. Someday I will have the time to build myself a pair
http://www.bellaextreme.com/bella%20custom%20builds.htm
