i need a small recorder to record mostly sound effects, i will use it with a couple of ms mkh40-mkh 30,
does anyone of you know tascam dr40 and tascam dr 100? what are real differences, about preampo and sound quality ?

David - Here is a pretty good comparison: http://dancarrphotography.com/blog/2012/01/03/new-tascam-dr-40-and-dr-100-mkii-for-dslr-audio/

(Dan is wrong about the mic input levels on the DR40 - with the new firmware upgrade, they are now independent).

The bottom line is that the differences between the two recorders are all about features - sound quality is pretty much the same.

Summary of the differences:

The DR100 has separate headphone and line outs, the DR40 has a combination line/headphone out

The DR100 has a rechargeable li-ion battery pack, the DR40 uses AA batteries

The DR100 has 4 built in mics, the DR40 has two

The DR100 has more physical controls, the DR40 is more menu driven

The DR40 has only two real advantages over the DR100:

The DR40 has two 1/4" TRS/XLR combination inputs, while the DR100 has XLR-only inputs, and

Lower cost.

I wanted the DR100 MkII's separate headphone and line outs, but for me, the most compelling argument was cost, so I bought the DR40.

I have been more than satisified with its performance.

Good luck with your decision,

Bill
Hybrid Camera Revolution (http://hybridcamerarevolution.blogspot.com)

considering that I need it to record sound effects with external pair of microphones in a boom, i just care about phantom, good preamps and how long battery life is. there's no lithium battery inside the dr 40 thats may be a problem.

Neither the DR-40 or 100 has very good pre-amps, but in this price range, the Tascams' are as about as good as your gonna get. For recording quiet sound sources, noise may be an issue. Using a quality high output level mic would help minimize the noise.