When we first started making this list over 6 years ago, there weren’t that many good quality headphone-specific amps available. But today, we have a great many high quality products to choose from, and the DACs have improved as well. This has actually made it more difficult to choose “the best.” In fact, among most of the higher-end products, your choice is really about features and “sounding different” (and the flavor YOU prefer) rather than “sounding better.” Of course, some of these amps appear to have better synergy with certain headphones than others.
Here's a variety of Headphone amp suggestions from our resident audiofools– keep in mind they have their own biases. Some units are amps only, others combine both DAC and amp. Prices may not be accurate. This is not meant to be the Holy Grail of information; just to help point the buyer in the right direction. In no particular order, but grouped by type as possible.
Pathos Aurium – Hybrid tube and solid state (MOSFET), more analytical sounding than the WOO (see below), has great features like Gain & Balance controls. $1400. Amp only, no DAC.
Pathos InPol Ear – tube-hybrid fully balanced amp to drive anything, but also functions as line level preamp and includes a DAC with streaming. Uncheap at $4500+, but very nice.
WOO Audio WA6-SE – great tube sound if you want to be in SET heaven, not very expensive. $1200.
ALO – check them out if you’re a tube fanatic and don’t want the WOO WA6-SE
Ampsandsound – They make a range of products and are dedicated tube fans who love "the classic tube sound."
Manley Absolute – A modern classic tube amp that follows that company's quirky and trailblazing aesthetic. $4500.
Nagra HD DAC – Frighteningly good hybrid tube amp/DAC combo. It you have too much money, you seriously need to demo this product. Don’t say we didn’t warn you.
Audiovalve Luminare – Excellent tube amp, especially if you have both high and low impedance headphones and/or Stax Electrostatics. No DAC. About 3,000 Euros.
Linear Tube Audio Z10 and Z10e – Both are fully tubed and transformerless, and also function as 12 Watt speaker amps with a surprising amount of drive. The full output of the amps are also directed to the headphone sections, for extra power and clarity that can drive any of our models easily. The Z10 is about $5k, with an option for MM phono stage.
If you have electrostatic headphones as well as planars, the Z10e is a special product. About $7k, but worth it if you can use all it offers.
Linear Tube Audio MZ3 – The evolution of their original amp, this is a lower-powered version of the amps above. It works well for any of our models, but is not quite the best authority for the 200 Ohm LCD-4s.
Chord Hugo TT2 – Excellent. Different DAC sound than others due to their own FPGA implementation (we use Chord DACs at every trade show). $4,500. For an even bigger thrill, add the M-Scaler for $5k.
The Hugo2 and Mojo are great portable solutions, too (see below). If you have an LCD-4 and need a portable amp/DAC, then the Hugo2 is your best choice.
If you have the financial resources, then give the DAVE a listen, and add that M-Scaler while you're at it.
Burson Conductor 3 Reference DAC and headphone amp and line level preamp (they have a killer all balanced version called the 3x) and streamer. This a DAC/preamp/headphone amp in one box, and is sonically excellent. $1,799 - $2199. And if you have hard-to drive headphones, this amp is a great solution (especially in balanced mode).
SPL Phonitor X – has a great feature - spatial controls! Plus, 3 inputs, and balanced in/out. $2k+, and can be used as a line stage preamp. Use this with the Audeze XC or X for studio mixing. And check out the Phonitor E in balanced mode too.
Headamp GS-X mkII – Great balanced amp for driving the LCD4s!
Mytek Brooklyn & Manhattan II. Great products. They also do MQA.
Questyle CMA800R – Very good amp. We also love the new CMA 400i driving the LCDi4 in-ears in balanced mode.
Pass Labs HPA-1 – A great headphone amp with line level preamp. Beautiful sounding. Maybe not quite enough gain for the LCD-4 if you like playing REALLY LOUD.
Prism Sound Callia DAC/amp – Great product. Linux support! About $2000.
Matrix M-Stage HPA-3U – a best buy at under $400 (via Amazon). This appears to be similar in circuit design to the Lehmann headphone amp from Germany.
Matrix Audio Quattro II Amp/DAC – Once again, a best buy at only $899. This is probably your best choice for a balanced output headphone amp with DAC at less than $1,000.
Cyrus Audio Cyrus ONE – a great headphone amp and integrated amplifier (even a phono preamp and Bluetooth are included!). About $1000.
DCS Bartok – Another FPGA-type DAC with an optional headphone amp. Great product, great sound.
Weiss DAC502 – Loaded with features and will soon have Audeze's LCD target curves from Roon and Reveal built-in to the firmware.
Simaudio MOON 430HA – Many features, will drive the LCD4 in balanced mode. $4,500.
Bryston BHA-1 – $1,395. This is also one of the few amps with a balance control (like the Pathos & SPL) – more necessary than you might think as everyone’s left and right ears are different. And this is a powerful amp for the LCD-4.
Lehmann Audio Linear – A very good sounding amp, $1100
Schiit Mjolnir – If you can pronounce the name, then this is a very good balanced amp. $850 direct from them.
Schiit Ragnarok2 – An integrated amp with full power sent to the headphone section, provides plenty of power for any of our headphones, especially if you run it balanced. $1450 with options for DAC and phono.
Benchmark HPA4 (amp only). This Balanced amp will drive the LCD4s. It’s an amazing line-level preamp as well. And we love it has a balance control! $2,995. Incredibly low self-noise! Also, check out their DAC3B.
PS Audio DirectStream Jr
Chord Qutest (add the M-Scaler if you can)
Resonessence Labs Mirus
Holo Audio Spring or May
Portable battery powered headphone amp+DAC
Sony PHA-3 – Excellent (ESS Sabre 9018 DAC), AND balanced outputs! $995
Periodic Audio Nickel - Amp only. Great solution for cellphone users. $299
Chord Mojo and Hugo2 – Their DACs use a unique topology, and we use them at trade shows. $500 (Mojo), $2500 (Hugo2)
Audioquest Dragonfly – they make three versions, and all are good on-the-go options for our lower impedance headphones. $100 - 300
IFI – They make a number of headphone amps and amps/DACs, from portable units at $299 to the Micro iDSD at $600 that has LINUX support and MQA.
For more info, impressions and opinions, we'd recommend publications like Stereophile, or an online forum such as Head-Fi.org, etc.