Thanks all for the great replies.
I think the OP is doing soundscape or sound effects gathering which is why he is looking for quiet pre-amps. IMO the M10 fits the bill recorder wise and this noise Schr is describing is probably as gutbucket surmises. Self-noise with the mics/or battery box malfunction.
What are the specs on those mics Schr?
BSM-7 specs:
Frequency response: 20- 20,000 Hz
Signal to noise ratio: 62dB, 1khz at 1pa
Open circuit sensitivity : -35dB (5.6 mv) re 1v at 1pa
Dynamic range: 95dB, 1kHz
Maximum Input Sound Level: 105dB SPL , 1kHz at 1%
Indeed it is a variety of dynamics that I record. They can be very loud bangs etc, or they can be the must subtle of sounds - say the quiet swish of silk or the subtle movement of jewellery.
The reason I absolutely LOVE sound devices for sound effects is the noise floor (I've mostly used a 702 but we had one of the bigger ones too). Sometimes we are busy performing sounds as well as recording them, and the inbuilt limiter is great for when we take our eye off the ball, but the low noise floor gives a lot of room for turning up in post-production.
When I bought my cm3 I probably should have bought a second matched one so they could double as general soundscape recording microphones. Alas I have the MM BMS-7s and I have actually really rated them in the past for what they can do for such a low price, so decided against it in the financial uncertainty of covid! I use those to record bird noise, general forest ambience and the like. Occasionally I wear them stealthily (probably like you guys in gigs) and walk around trying to capture general chit chat whether it be in pubs, libraries, out and about town etc! That worked excellently going from the 9v battery box into a Roland R26 (my favourite handheld recorder, sadly I do not own). I suspect the noise I am hearing is indeed the general sound of the microphones - it is also heard when plugging them straight into the m10's line input.
A word of caution: Make sure you are using the 3.5 mm TAPE OUT to connect to the LINE IN on your M10; and not the XLR Line Out on the FP24. That puts out a much hotter level which can overload the M10.
Another question for all you all you m10er's in the know... with regards to setting the input gain to "4" when using with a preamp... is this with the recorder set to high or low mic sensitivity, or does that not matter when using the line in?
CM3 > FP24 > M10 is a solid combination I used for years (and still do on occasion). These two tracks were recorded with that exact chain:
Mixed chamber choir; medium placement
HS women's choir; close placement (pardon the digital piano)
Sounds excellent!
The caveat is that I'm an amateur music recordist with little expertise in either of those fields! Schr, keep in mind that amateur live music recording is the primary background of most everyone offering advice here, so consider most of our suggestions in that light.
Totally understood
I am very much listening to the technical advice and combining it with my experience of sound effects recording in the past 5 years or so!