I purchased a new DP008ex, and I noticed that I get very different recording levels with each of the two built in mics. Both are set at the same "high" level. If I play acoustic guitar directly in front of the unit with both mics armed and at the same preamp gain level, the signal is about half as hot on input A. I can get a usable volume out of Mic B, but not really Mic A. Is this normal or a quality control issue? I like the unit in general, but I'm wondering if I got a lemon and need to exchange it.