These are fantastic preamps, fully tested, and professionally built. If you want that vintage API tone, this is the best way to get it! These are favorites on acoustic instruments, drums, electric guitar, etc. The VP25 is identical to the VP26, but has a larger output transformer, and a bit more low end extension.
Note, these are the stepped gain version, with the Litz wire transformers, both of which are upgrades to the stock model.