the mkII are the newest version, i highly reccomned these mics for toms and heavey guitar, it has changed the whole scope of my drum and guitar sound
hope that helps alittle

thanks

for now I can't afford a Mk II
so I'm looking for a second hand Mk I

even within the Mk I
there seems to be quite some variation
sometimes called 421-u5 or -ux (something)

what's the difference?

cheers

couldnt tell you. i am sure someone on this board has all of the :wink:

try this link

http://www.coutant.org/md421u4/

also use the contents button on top, all sorts of mic description

SI

The original MD421-UL was made from some sort of metal alloy (zinc, I think). This is what is shown in the website listed in the above post (features a 1985 photo), and the differences sited were electical connections. Later on, somewhere in the 90s, Sennheiser came up with a "new" version, the 421-II. It is constructed from some sort of high-impact plastic, and is a bit slimmer. These 2 traits make the 421 a bit easier to stick into a drumkit without being smacked, and if it is smacked, it tends to hold up better. The sound of the mic changed when they made this transition, possibly due to the transformer/cartridge upgrade that was made at the same time. These "II" mics tend to have a bit more snap in the top end. If you are looking at buying any used 421s, make sure that they sound "right". They are fairly tough mics (compared to other German dynamics), but they can get beaten up to the point that the cartridge is whacked out of place, and that gives them a "hollow" sound. If they look beat up, be careful!