Time code generated in file-based recorders is fundamentally different than time code on a tape recorder. Whereas a tape recorder has a continuous time code reference for each location on the tape, a (broadcast wave) audio file only has a single time code value—from which all time code values are calculated.
The line-level inputs on the 302 and 442 are attenuated by 40 dB from mic-level and go through the mic transformer. We chose this topology to maintain transformer isolation of line inputs. For our portable field mixers we chose to keep their size small and not have transformers large enough to handle line inputs. The alternative, electronically balancing line inputs along side transformer balanced mic ins, was not practical. The noise penalty is extremely small, since the noise figure of the unit overall is quite low.
Rechargeable AA batteries for internal powering of pro audio gear have historically been poor performers. Alkaline primary cells, and more recently Li-ion cells, are usually the preferred cell chemistry. Fortunately, battery chemistries have evolved -- in some applications there is actually a runtime advantage when using the newer NiMH rechargeable batteries with portable gear versus alkaline cells.
The input channel peak LEDs indicate both pre- and post- fade peak levels on the 302. In early production mixers (before 2005) there are two resistors which make channel 2 and channel 3 not indicate post-fade peak levels. This minor condition is fixed on later units. Note that if the channel fader is below unity gain the pre-fade input will always clip first (and be indicated), and if the fader is above unity, the output (as displayed on the meter) will always clip first.