Anyone knows about the lack of preamps to provide extreme gain setups? Even my sound devices 702 gets very noisy at the end of the gain range. Today i stumbled across this little device. It's a pre-preamp by Triton Audio. It provides the signal to the recorder preamp with very low noise and a hotter signal. Did anyone of you test this device? Here's the link: http://bit.ly/1sev521
I've no experience with this type of gear, but functionality depends on the use-case.
This device (and there are several others available with similar function) is mostly useful on ribbon and dynamic mics. But in most cases, as a sound designer or sound engineer, those types of mics are used on loud objects (drums, guns, explosions, cars).
If you want to capture really quiet sound sources (i guess you want to crank more dBs out of your mics) a phantom powered condenser mic (large or small capsule) with a very low self noise (Sennheiser mkh series, rode nt1a, Neumann TLM103) are what you need.
I've recorded very soft sounds with my mkh50/60 paired with a Sonosax recorder.
Hiss will not be an issue until you step into an anechoic chamber.
Perhaps you can elaborate on what you want to record and which mics you use?
There is a great article on http://chromonaut.ch/2013/boost-zoom-h4n-recordings/ I have the same problem but haven't tested yet. They speak about problems with the Rode NTG-2, portable recorders and the Fethead phantom, anyone experience with that? Is there a problem with all condenser mic's?