6th Gen KORG Nutube - An Engaging, Unique Vacuum Tube Sound Provided by KORN and Noritake, the 6th GEN Nutube operates exactly as a conventional triode vacuum tube and creates the same characteristic rich overtones that are sought after in triode tubes. At the same time, the Nutube achieve substantial power saving, miniaturization, and quality improvements when compared with a conventional vacuum tube. The AMP13 competes voltage amplification through the vacuum Nutube, while giving AMP13 An Engaging, Unique Vacuum Tube Sound, delivering excellent linearity. 3.5mm+3.5mm - Unique Dual Single-Ended Outputs The voltage amplification capability of the Nutube 6P1 is limited. Two stages of amplification are necessary to obtain higher output power. To have both a stronger tube signature and a higher output power, the AMP13 adopts a dual 3.5mm single-ended output design with low noise tube output and maximized output at the same time. Low Noise Tube Output: The AMP13 utilizes Nutube 6P1 as a voltage amplifier. This is followed by a digital volume control and current amplification. The low noise tube output is the output after the first stage of amplification. Although the output is not high using this design, the Nutube has a stronger tube sound signature and noise control is excellent. (2.5Vrms) Maximized Output: The output passes through a first stage Nutube amplifier, followed by a secondary amplification. With this, the AMP13 has a higher voltage and current output capability, that is, a better driving capability for headphones and IEMs. (4.1Vrms) Three Channel Amplifier - Unlocking a Better Performance The single-ended output of ordinary players general only has left and right dual-channel amplification. Although the Nutube 6P1 has the same characteristic rich overtones as conventional triode vacuum tubes, its low output capability and poorer noise control have always been a design problem. On the AMP13, iBasso uses three-channel amplification. Utilizing the OPA1622to amplify the output ground signal, the noise floor is dropped substantially while enhancing dynamics and Improving the Nutube performance. Dedicated Battery The AMP section of the DX320/DX300 has its own battery power, which is perfect for the AMP13 utilizes two pieces of high-performance DC-DC chips from Linear Technology, with a total of 4 DC-DC power supplies. One DC-DC is 1.8V for the cathode through a low-noise LDO, and one is 21V for the anode of Nutube, one is +8V and one is -8V, which constitutes the 16V voltage swing that feeds the OPAMPS. Hand Matched - Every Unit Is A Masterpiece Each AMP13 is tested and matched with an AP audio analyser, with 3 multi-turn potentiometers on the AMP13 board, which are manually calibrated and matched by engineers to present the optimal performance of the Nutube. The AMP13 brings a clean extended upper frequency and a sweet and engaging sound together for your musical enjoyment.