Answers to more questions may be found here.
Autolycus pickups have been used worldwide for well over ten years. They are known to be reliable and good value for money out-performing units costing far more. The following may be noted.
A pickup which fails to work will be replaced if returned provided it has not been abused or visibly damaged. Never bend the flat element on the end of the wire.
Autolycus pickups respond to the sound produced by the body of the violin. The sound produced and subsequently amplified will reflect the quality of the instrument to which it is fitted.
The characteristics of the Autolycus pick up allow a fair comparison with the sound when using a microphone. With only modest tone control it may be hard to tell the difference.
Feedback is substantially delayed using the piezo device when compared with a microphone.
Autolycus pickups are a high impedance device and need a relatively high impedance pre-amp for best results. Several combo amps now have inputs specifically provided for this purpose and many high impedance foot pedals are suitable. An input impedance of one megohm is usually high enough. It is also recommended that cables into the pre-amp should be kept short.
A modest use of reverb or delay, much like the vocalists enjoy, can improve sound levels. Experimentation is always encouraged but too much "effect" can quickly be overbearing.......'a matter of taste / opinion!
The mass (weight) of an Autolycus pickup is very small. Its effect on acoustic tone when mounted on the top plate as recommended is not significant. It is unlikely any ear would detect a change in sound.