This device combines a low and a preamp direct box. One of the big advantages is that you can send the processed signal to a power amp, and, separately, the direct signal to a mixer, for example. but of course many other combinations are possible.
The operation of SABDDI (acronym for SansAmp Bass Driver DI) is based on three potentiometers Magic: the drive, the presence and blend.
The first defines the saturation level desired (note I said saturation, no distortion)
The second allows, as its name indicates a signal to get over this
The final mix, as desired, the direct signal from the bass and the retired
This model is not rack-mount, which also will soon take me to buy the SansAmp RBI

UTILIZATION

The SABDDI is very simple to use.
The manual is simple but enough to teach the basics of operating the device

SOUND QUALITY

This is the only preamp I see transistors capable of reproducing very accurate grain of tube amps (for low, I get along)
From this point of view, Tech 21 has done an absolutely remarkable
I use this preamp between my Ampeg B-100R and my basses: a Fender Precision and a Rickenbacker 70's 4003
I get it sounds huge, with the only regret background noise quite important, especially when it boosts the presence or the drive

OVERALL OPINION

I have this camera for a year and a half
I appreciate its simplicity and the fact quickly find a warm and powerful sound
As I said above, I regret that it is not in a rack, and background noise bothers me a little
I also have a Bass Pod, it is not at all comparable. To simulate the Ampeg, the Bass Pod is far behind
The value for money of SABDDI seems excellent (I had to pay about 300 euro, or a little less I think)
If it again, at that price I would do