1. xDuoo MP-01 Tube Headphone Amplifier, 2. Massdrop Objective 2 Headphone Amp: Desktop Edition, 3. Drop + THX AAA™ 789 Linear Amplifier, 4. Drop O2 [Video] Street Fighter V player Alex Myers unboxes and reviews a gift from Massdrop – the Koss Porta Pro X Headphones! Drop exclusive price and reviews: Topping DX3 Pro DAC/Amp Massdrop x Koss KSC75X On-Ear Headphones $20. Cayin RU6 Portable USB DAC/Amp Dongle $189 $249. 10. Featuring a popular Cirrus CS4344 DAC, the DAC-X3 is a big step up from the digital-to-audio converters built into today’s portable devices and computers. It also includes a built-in headphone amplifier for driving low-impedance headphones. Connect your setup in seconds with a headphone output, RCA output, optical input, coaxial input, and All music sounded like shit with bass in all regions. When I got the ksc75's, everything sounded right. The parts express headband is a better upgrade if the earclips get on your nerves. The thing is the shipping price is high because they toss in a multifunctional wallet tool that adds considerable weight. 1. I might not have ever tried the Porta Pros if not for the $20 Massdrop KPH30i. Those started my obsession with Koss. Now I have four pairs of Koss on-ears 🙃 Introduction. The Koss ESP/95X is a (now discontinued) collaboration between Drop and Koss to produce a cheaper, nonportable version of the latter's electrostatic ESP-950. The ESP-950 is a long-enduring headphone system with a stock energizer, having existed for decades and remaining unchanged in price and design to my knowledge. ‎Porta Pro X : Model Name ‎Massdrop x Koss Porta Pro X : Model year ‎2019 : Part Number ‎MDX-14771-1 : Hardware Platform ‎Smartphone : Compatible Devices ‎Laptops : Special Features ‎default_no_selection_value, Lightweight, Microphone-Feature, Tangle-free-cord, Universal-phone-control, Foldable : Mounting Hardware LCw8Z7.