Yes, it's the line-in input I'm having troubles with. The mic input works fine (I switched the input gain from low to mid and the levels are quite good now with input level around 80-90).
I don't think it's a battery box problem (I don't have a spare battery to replace it in the CA battery box). I tested also my SoundProfessionals battery box and mics and although the resulting level is about twice as high as with CA-14, it's still very low.
This is the resulting WAV file opened in Goldwave (line-in input = 100). First half recorded with CA-14 and CA battery box, second half with SP-CMC-9 and SP battery box.
http://www.queenconcerts.com/tmp/goldwave_tascam_linein.jpgYou can see I'd have to change the volume to about 1500% to actually hear anything. When I record, the Tascam recorder says the input level is "-43 dB". WIth SP-CMC-9 the input level is about "-30 dB".
I must have overlooked something. I'm not buying a preamp, I've been recording loud rock gigs for years (with minidisc recorder or Edirol R-09 HR) and never had any problems with volume with any other recorder, in fact it's vice versa and I usually have to keep the input level low. I must have overlooked some setting on my Tascam, that's the only explanation I can come with. It's not just the dual mode, the result is the same when I record just line-in.
If I record a gig in this "silent" mode and then amplify it in sound editor, I will get some additional hiss and the overall sound quality will get worse, right?