BM6A (Classic): differences between amp versions (mkI and mkII) and difference with BM6A MKII

What is the difference in the amps for BM6A classic and also with BM6A MKII

Difference

BM6A classic got 2 versions of amp, which are called mkI and Mkii amps. That creates confusion with the BM6A mkII which was a completely different product (see pictures below): 

BM6A CLASSIC                      BM6A MKII

BM6A MKII was launched in 2005 and discontinued in 2010. Drivers and amps are completely different on Bm6A MKII and the sound is different. 

Differences between amp MKI and amp MKII for BM6A classic

In 2001 the BM6A and (BM15A) amps were redesigned to comply ROH standards. The new version of amp called MKII has the same technical performances as the original amp. However, due to physical changes on the amp board (longer capacitors) the cabinet amp slot was physically modified to fit the new amp increased depth. So to sum up, here are the differences: 

- MKII amp is deeper than MKI amp

- MKII amp can't fit in an original MKI amp cabinet

- MKII amp has a rotary voltage selector - The MKI has a square selector

- BM6A with MKII amps have a serial number < 694457 (however exceptions may occur) 

- BM6A Classic MKII amp will not work with a BM6A MKII