When I reviewed the Tascam DR-40 a few months back, I felt that one of the main drawbacks to this affordable audio recorder was the absence of independent level control. Now with the new Tascam DR-40 Firmware Update that adds independent level control to its external inputs, this problem has been recognized and addressed. For those using external XLR microphones for their DSLR, this feature is fairly important as it helps in matching up different microphones.
The Tascam DR-40 offers features like dual locking combo-XLR inputs which supply phantom power and can be switched to accept true line-level signals and four-channel recording simultaneously.
You can also opt to record a duplicate safety version of two tracks internally at a lower input level setting. So if one recording gets a spike in volume and the main recording peaks and distorts, the copy that is recording internally will be free of distortion.
For full tech specs and a comparison of the Tascam DR-40 and DR-100, check out the original blog post (click here).