About our AIYIMA Our design concept is to satisfy more audio enthusiasts' pursuit of sound quality. The use of audio electronic products needs to be used in strict accordance with the correct connection and matching, so as to achieve the maximum use effect of the product. Through your computer and other audio source input to our A07 2 Channel Stereo amplifier, RCA output to your bookshelf passive speakers,The 3.5mm AUX of A07 Stereo amplifier output to AIYIMA A3001 subwoofer amplifier,to built the 2.1 channel system,this is undoubtedly a very perfect combination. We offer Brand technical support and service,any problem ,pls ask me!thank you ver much Let you enjoy HIFI music! Thank you for your choice!