Aune S17 Pro EVO Headphone Amp, Pre-amp, Fine Volume Curve, Pure Class-A Fully-Discrete Fully Balanced, 6.35mm/XLR/4.4mm Headphone Jack, Twin JFET, XLR/RCA Preamp Out, for DAC/Speaker/Home Audio

[Twin JFET | 2 Pairs Transistors Per K] JFET has high input impedance and rich sound. The Twin JFET of the S17 Pro EVO is more than that - same temperature increases, same performance, and stable center voltage. It is the ideal input transistor of a headphone amplifier. | The last output stage uses 2 pairs of output transistors in parallel. The whole device has up to 16 output transistors. Max output is as high as 7.5W. It can drive all kinds of headphones and IEMs with ease [Class-A, 2 levels of current/gain] 50mA/100mA per transistor; each K has 2 pairs of transistors in parallel, so that the quiescent current of each channel is as high as 100mA/200mA. The sound of a Class-A amplifier is smooth, warm, and sleek; 2 gain levels: the low gain utilizes the characteristic of the Class-A amplifier that the transistors always operate in the linear range to drive the LEMs well and correctly, while the high gain is as high as 7.5 W and can thus drive headphones well with great power [R2R Electronic Volume Chip | Rigorous HiFi Component Selection] Uses the JRC R2R electronic volume chip and the dedicated operational amplifiers to build the 4-fold symmetrical R2R volume control. High control precision, great channel balance, wide sound stage, accurate positioning. The components are high-quality and carefully selected, such as the electrolytic capacitors, ceramic capacitors, organic thin-film capacitors, communication-grade PCB, etc. Everything is focused on good sound [2 Colors to Display Current Level/Temperature|Overheating Protection|3-Dimensional Cooler Structure] The 100mA mode is a high current class A operating mode, similar to GT mode in a racing car. There will be a slow temperature rise. (If the headphone impedance is low, this can lead to a faster temperature increase.) When the device temperature reaches 69°C, the S17 Pro will automatically switch to the 50mA Class A power mode due to the overheat protection, which still maintains very good sound quality Powerful and rich sound | Aesthetic tuning The S17 Pro uses the 50W toroidal transformer and dual-power design. Digital control and analog are independent of each other, so that the analog part can be free of interference. It also features the 19200 μF capacitor array. Together they make the S17 Pro so powerful and rich sounding. The sound is based on real instrument tones and music pieces, resulting in a signature that is natural and full of musicality