We also never use the 170 as mains as we have a lot of much better options.
They are, however great as allround spot mics, and has become my favourite bass and french horn and general string spot.

Someone earlier suggested an AEA R88 large geometry stereo ribbon. I love this mic! Its got an old-school vibe and costs about $1,000 less than an SF-12.

DACS input impedance is around 1K ohm. I love mine and use them successfully with both AEA and Royer ribbons and condenser's too. The Forssell SMP-2 is even more transparent and its 15K ohm input impedance is even better for ribbons. Like the DACS it has phantom powered inputs and separate DC inputs that bypass phantom power and blocking caps. An SMP-2 is $2,000, a few hundred less than a DACS. The next preamp of this kind that I buy will definitely be a Forssell.

Just an update

The recording session was last weekend, it went very well.

Managed to get a loan of a Royer SF-12 and a DACS Micamp, the combination was absolutely superb, warm and rich! Also managed to get an Earthworks SR30 (not a pair so couldn't compare to the Royer) and used this on percussion. There was one piece with a Xylophone solo and the Earthworks made it sound so sharp!

All round both were very good. But I'd go with the Royer SF-12 for a stereo pair in future

FYI: The AEA Ribbon pre amp was designed by Fred Forssell, though I would agree that the SMP-2 is a better unit.

Congrats!

Ribbons in Blumlein are great but the downside is they can sound more or less boxy depending on the room. Having spot or room mics in the mix really helps raise sonic interest so the image doesn't just sit unmoving. Another helper is a Blumlein shuffler like the Waves S1. Just a touch does the job nicely.

I agree: there's no ONE perfect mic/setup for every situation, but this one is beautiful on instruments in a musical space. Sometimes low-mids can be murky, but placement is everything - having an assistant to move it around is very helpful (or having a VERY long headphone cable if the recording rig isn't too far away!), but when you find the sweet spot, it's remarkable. Quite often you'll find no need for spots etc. if the ensemble is balanced. IMO, brass and ribbons are a very happy marriage.

I sometimes prefer SDC's too, and will say the Earthworks TC30k's can sound pretty impressive. They're more flattering than I expected: kind of a 'virtual reality' presence if they're not spaced too far apart.

Really depends on your budget - there are a lot of great options, most with a hefty price tag.

Best in the quest,