LS29 is base on  the  HI END Audio manufacturers-Music Fidelity's X CAN series .
LS29 is very simple, it is easy to install and cheap, sound and good, you only need to add a 24VAC transformer and then connected the RCA input and output terminals, then it can sing. 
it can add a volume control VR into the buffer before the class. Come even more exciting, it can change the magnification, the general design of the former class into the use of sound is also great Oh! To play more praise you? two LS29 can be used to set the first buffer, then after VR, and then enter into another set to a gain for the former level, so the composition of the sound, a full can match tens of thousands of pre-market asking price level Oh!