The range of good mandolin pickups is smaller than that for guitars but there are a few that work well.
I build my mandolin family instruments with a bridge designed to take an under-saddle pickup. I prefer a slightly lower, solid bridge design over the Gibson split bridge and it means that I can utilise the great sounding and reliable Headway pickups which takes the hassle out of deciding which route to take when amplifying a mandolin. If the mandolin has a traditional Gibson split bridge or earlier version, then another route needs to be taken and in which case a good contact transducer is the only option other than a purpose built piezo bridge.
Under-saddle
Headway HE4 This is a great purpose built mandolin under-saddle utilising a piezo cable. It’s preamp is EQ’d for the job and gives an unusually transparent and yet robust signal perfect for the gigging musician. If you want a no messing great sound, this is the one. Use with or without a good off board preamp. Sound hole mandolins only.
Headway Snake The Snake is a version of the above with a more basic preamp encased inline rather than mounted on the endpin jack. It is a more affordable version of the HE4 and works extremely well when coupled with a good preamp with EQ like Headway’s own EDB2 or Baggs Para DI. I have used this in a number of my own instruments.
Contact
LR Baggs Radius I’ve only fitted two or three of these and still playing with this one. Positioning is everything and I would certainly only recommend an external mount. A potentially faithful mic -like reproduction – a magnetic film is mounted on a small beam within the casing. Two magnets dampen the response to give a robust, feedback resistant signal with warmth and natural dynamics. Gives a friendly, high output, don’t have to EQ too much if the positioning is spot on although a notch filter is essential so off board pre amp recommended.
K and K Two head version of the Pure Mini. Transparent and robust. Can be fitted internally to f holes depending on the f hole size. Can be fitted internally to sound hole models. Need K and K external preamp or Headway EDB2.