Any type of stealthing, including the latter type you recommended. Metal isn't the problem; it's the size, and it's a good point you made that their size is almost the same.
Without the battery, we're talking 1.3" and .3" additional, which isn't much. It's the
square shape that makes it challenging to walk in.
5.68” x 4.35” versus 6.53” x 4.65”
For reference, a Sony M10 is 4.5" x 2.5" area, and I find that easy to bring in anywhere.
A Sonosax SX-M2 preamp's area is 5.75″ x 3.4″.
I'm debating on MixPre-3 (and using Sony M10 for extra channels), or getting the MixPre-6. Need to determine if the 6 is small enough for stealth.
what type of situation are you referring to by stealth, exactly? i just got a mixpre-6 recently, and i certainly consider it to be stealthable in terms of shows where open taping isn't allowed at small clubs that have no security -- the types of shows where there's a ticket taker and ID checker and otherwise you just walk right in. if, however, you're referring to being able to get the mixpre-6 (or 3) into arenas and other venues that use walkthrough detectors, wands and thorough patdowns, probably not. without getting into stealth talk too much, as that's frowned upon around here, you'd definitely have to be really creative and go above and beyond the norm to make the mixpres work in that scenario. i'm not planning on using it in those types of scenarios. and furthermore, i'm not sure the size difference between the 3 and 6 would be big enough to make a difference in this regard, as they both contain quite a bit of metal i think, and both would be easily found by any semi-competent door search.