Bellari HA540 Tube Headphone Amp The Bellari HA540 was built for those of us who have lusted after tube headphone amplifiers only to be dismayed at the enormous expense. The HA540 is an honest to goodness zero feedback Class-A, all tube headphone amplifier in a very compact chassis. How good can it be at this price? Excellent, actually. Just like Bellari's outstanding phono preamps, the HA540 offers an extremely detailed, rich, bold sound with a surprisingly reasonable price. The HA540 is a very flexible design with a lot of great features that should be standard on every headphone amp. The first great feature is the visible 12AX7 tube. This gorgeous, capable amp drives headphones from 16-2k Ohms and offers both 1/4" and 1/8" outputs. Input selection is also quite extensive, with both an RCA and a Mini-Jack input (selectable). The HA540 is also designed to extract maximum performance from any source with two types of inputs to match any source. We love the sound from this all-tube headphone amp, and we know you will, too. Two Types of Inputs To ensure the best sound possible from any source, the HA540 has two different input types, Low and High. High is for devices with robust output stages like full-size CD players, tape outputs from a preamp or receiver etc. Low is a special input which offers greater gain for portable devices or any device that doesn't have a robust output stage. Why is this necessary? Imagine the HA540 sitting on your desk at work. The High input is connected to your high-quality USB DAC and the Low input is connected to your iPod, XM Radio tuner or portable radio. The two types of inputs can be selected from a top panel selector. *NOTE: There are two Low connection options, Mini-Jack and RCA. This allows either a Mini to Mini or a Mini to RCA cable to be used. These are either/or inputs, please don't use them simultaneously. All Bellari products are manufactured in the USA