Experimenters should be aware that Ambient's active DC to DC conversion circuitry-equipped HHA-S adapter costs roughly USD $300 (incl. shipping) in order to mount just under a (further) thousand dollars worth (USD) of Neumann KK104 or KK105 capsule.

Rat Sound's passive adapter is, however, a much cheaper "gamble".

On the face of it, my feeling is that both adapters should be compatible from a purely technical standpoint, ...but tolerances in respect of the clearances from the adapters' concentric "tracks" to the "pogo pins" of Line 6 handhelds may require physical attention (such as the filing down of an adapter's "lip" for deeper "screwing in") in order to achieve reliable connections.

I'd really love to hear reports from anyone who's been able to try either, as all the capsules you mention (particularly the Neumanns) have long been firm favourites.

In that light, I must add that Line 6's inbuilt "835" and "935" models "do the job" for most of my "Sennheiser" vocal applications, however I've yet to find anything that matches the effortless detail and smoothness granted by two Neumanns' on stage rendition of powerful vocals, particularly in the range from mezzo down to bass.

If only I didn't need to come up with the cash...