Thanks for the feedback Bruce.
I looked at the schematic of the 3630 to see what exactly the bypass switch does. The heart, so to speak, of a compressor unit is the VCA (Voltage Controlled Amplfier). Alesis shunts the input of the VCA to ground which
should not discolor the sound, but there is, of course, more to the unit than just the VCA. I'll have to study it a bit more to see what else is happening in there.
The VCA IC used is a 2150. I was surprised to find that the IC was designed by dbx.
THAT 2150 Series integrated-circuit voltage-controlled amplifiers (VCAs) are the original VCA ICs developed at dbx, Inc. in the 1980s. They are high-performance current-in/current-out devices with two opposing-polarity, voltage-sensitive control ports.
They offer wide-range exponential control of gain and attenuation with moderately low signal distortion. The parts are selected after packaging based primarily on after-trim THD and control-voltage feedthrough performance. In-circuit adjustment is required to achieve the guaranteed distortion and feedthrough performance. (It could be worth looking into just how this "In circuit adjustment" is accomplished. Perhaps something can be done there to change the performance .... for the better that is. 
)
The 2150 Series is fabricated in a super low-noise, junction-isolated process utilizing high hFE, complementary NPN/PNP pairs. They are available in three grades, selected for distortion, allowing the user to optimize cost vs. performance. (Ah-HA! "... cost vs. performance. Perhaps Alesis goes for cost at the expense of performance in selecting the grade of IC that they use? Perhaps, since the various grades would be pin for pin compatible, it would make a large improvement to swap out the existing VCA's with the highest grade device.)
Note that the 2180 and 2181 Series VCA ICs offer superior performance at similar prices to the 2150 Series. Furthermore, the 2180 and 2181 Series ICs are pin-compatible with the 2150 Series. Therefore, we do not recommend using the 2150 Series in new designs. Nonetheless, these parts will continue to be available for the foreseeable future, based on customer demand. (Forget the above "grade swap" comment. I'll just try the new 2180/2181's.)
It looks like the 3630 has a sound (good practice) design, but perhaps they use lower cost components in the circuit. Changing them for higher would make it a good unit, given the sound design, at still a great savings to other units.
We'll see . . . .
As far as the gates are concerned? I don't even use them. I get really bad results with them but most of that at least is likely me. Like if I try using them for vocals? Half of what I want to record would be missing. Adjusting them down a bit would just make them stay on. ???
Larry
