Multiple audio inputs and outputs for different use purposes: With 3.5mm AUX/Stereo RCA/Bluetooth inputs, compatible well with almost all home audio devices. With 3.5mm AUX and speaker outputs, can be used as a tube preamp to improve the sound quality for other amplifiers or active speakers, also can be used as a tube amplifier to drive passive speakers. Pluggable Vacuum tube design and HiFi sound: using 6J4 tube, sounds warm and delicate, full and mellow, much softer and more listenable. Can be directly replaced by 6J1/6J4/ GE5654/6AK5/6*1N to enjoy different sound styles.
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