Douk Audio U3 Mini Class A Headphone Amplifier Hifi Desktop Home Stereo Product Features Adopting innovative circuit design, DC 5-20V wide input working voltage, the amplifier circuit can always work at a high voltage of 26V, and the background noise index is excellent. With wide frequency response extension, excellent transient response, excellent purity and transparency, and good dynamic range. Adopting original TI-NE5532 classical op amp and transistor expanding current circuit, using 1300mA large current output transistor working in class A status, with ultra-low distortion, and the sound is warm and delicate, full and mellow. Pluggable op amp socket design, convenient to upgrade different op amps and bring much DIY fun and playability for audiophiles. Smooth and mellow sound, suitable for listening to vocals or string music, classic or pop music, and even with unique charm when playing rock. Mini size with exquisite appearance and most cost-effective, brings big surprise for all audiophiles, easily to drive most headphones in the market, providing larger power, better sound field and details, very suitable for home/office desltop audio system use. With strong drive power, easily to drive most high-impedance headphones such as: HD580/HD600/HD650/K701/K702/Q701/DT880/T70/T90/SR225/SR325/RS1e Shipping: Shipping is complimentary within the lower 48 US States. We Do Not Ship to PO/APO Boxes, HI or Alaska We Do Not Ship Outside of the Continental US All items ship within 24-72 hours of Payment For large items that require Freight shipping a valid phone number is required to call and schedule your delivery Terms of Sale and Feedback: Feedback is extremely important to us and If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority! If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns. We PROMISE we can make you happy if you give us a fair chance. Returns / Concerns: All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority! All items are IN STOCK at time of listing. Inventory changes constantly and it is impossible to maintain a perfectly accurate count of all items. Please do not penalize us if we have to issue you a refund! Thank You For Your Business!