here is a recording of my dual pickup/mic system for mandolin. Played here on my F style mandolin with information on how it was recorded and the time location of what you are listening to.

Song form:  A1-A2

3 Mandolin Channels:

1)  On-board Mandolin mic

2)  On-board Mandolin PU

3)  Room mic (AES R84 ribbon mic placed approx 18” 

in front of mandolin)

First half of first A section (1A1):  00:00-00:24    

Room mic (AES R84) only.

Second half of first A section (1A1):  00:24-00:41 

Mandolin on-board mic only.

First half of second A section (1A2):  00:41-00:57  

Mandolin on-board PU only.

Second half of second A section (1A2) thru first half of 2A1:  00:57-01:35   Mandolin on-board mic & on-board PU only.

Second half of 2A1 thru to the end:  01:35-02:36 

All three sources together, On-board mic, PU and Room mic.

About the recording:

The session was recorded using Pro Tools HD Native v. 12.8.2

@ 96 KHz-24 bits at the Watershed Arts studio in Ithaca NY. The 2-track master was then sample-rate-reduced and dithered down to a CD-quality WAV file @ 44.1KHZ-16 bits. The mandolin on-board Mic & PU passed through a Grace Design ‘Felix’ 2-channel blending preamp then into 2 channels of a UA 4-710d preamp. The AES R84 was recorded through an AEA RPQ 500 preamp.  Guitar, electric bass, percussion, recording and mastering by Doug Robinson, .

more information here