| How the converters affects the sound through the internal pre or an external one is pretty much the same, as there's only one A/D in there. There may be electrical differences that may change the sound, but that all happens before the A/Ds. It's the source signal quality that really determines how it's going to sound.
The Firebox manual states it's mic pres have only 45 dB of gain, which isn't much (although typical for these kinds of boxes). What kind of preamp you want to use depends on what kind of mics you want to use. If you have a hot condenser you should be fine with the Firebox's built-in pres.
However if you're using a dynamic or a ribbon you definitely need more gain. Because the Firebox has line inputs this isn't a problem at all, just plug your external preamp in and set your gain.
Do you have a preamp in mind that you want to use? If not, if you want a clean, linear preamp consider the Rane MS-1b ($150-$200). This unit will give you 66 dB of gain, which is pretty decent.
For something more colored, look at the Golden Age Pre-73 Neve clone ($300). This will give you up to 80 dB of gain, although at the higher end it may get ratty if you have a hot input signal (usually you won't be up that high if you have a hot signal to begin with). It's my go-to preamp for my ribbons and dynamics.
There's plenty of preamp options out there, have a look around if you don't know yet what you want. |