WARNING
This list is not exhaustive by any means. I have not heard everything.

BACKGROUND

I copied this list from my post in HF since I’m perma-banned from the thread. Consider the HF post out of date. There are corrections and further elucidations here. And there will be more based on feedback from people here on this forum. Feel free to offer additional feedback. I'd like to make this more of a "Changstar" effort.

The list is by approximate price give or takes a few hundred - not in order of sound quality – and comments are only in relation to HD800, although possible to extrapolate them to other headphones. If there happen to be other headphones which gel particularly well with an amp, I will mention them.

THIS IS WHERE I AM COMING FROM

I only like the HD800 under certain conditions. The overall frequency response of the HD800 is a bit too screwy for my tastes. I find that EQ doesn’t work well for the HD800. Some of the strangeness of the HD800 is inherent from the internal reflections and refractions of the cup design. Arnaud ran a simulation to demonstrate this. Further “Free-air” / damped measurements seem to confirm Arnaud’s results. Therefore my preference to tame some of the HD800’s behavior is with mechanical modifications, namely variations of the Anaxilus Mod.

In general, the solid-state is not as good as the tube or hybrid stuff. The Ragnarok, which is competitive (but different sounding, but not that different) from the tube amps, is the sole exception.

Also, I've realized that I have a preference for amps with output impedance from 2 to 12 for the HD800. There are exceptions of course. Amplifiers of extremely poor value will not be mentioned in the list proper.

LIST OF AMPS FOR HD800 HERE

Schiit Vali - Extremely resolving for price. Tube wetness. Hint of warmth in bass. Smooth neutral / slightly bright treble. Tends to impart a certain quality to timbre, but not I’m gonna bitch for $120. I use it myself. At the time it was released (before the version 2 Schiit amps), it was better than most of the other Schiit amps. Tube microphonics can be an issue. If it’s bad, exchange it. That’s probably why it isn’t $99.

Matrix mStage - Warmish solid state if input caps are left in place. If you DAC’s offset is zero, you can remove the caps and direct couple for more clarity and a less warm sound. Lacks resolution and microdynamics compared to better brethren. Set at high gain. Consider resistor mods to push op-amps into cheesy class A.

Schiit Valhalla 2 - Probably top third of this list in terms of SQ. Yes, that's how good it is. Fast, clear, resolving - more than holds its own compared to Crack. Not as warm though and tends toward neutral presentation. Does not work nearly as well with low Z or low sensitivity orthodynamic headphones. Best to stick with high Z Senns or Beyers. Not an insult to Schiit or Eddie Current, but someone made an Eddie Current amp for $349. Anaxilus Mods preferred with Valhalla.

Bottlehead Crack - Must have the speedball upgrade for use with HD800. Warm (but again tubes play role). The 120 ohm output impedance could be a bit too much for the HD800. Not resolving and controlled enough compared to the best here to take full advantage of the HD800 capabilities, but a good value proposition especially if you can DIY and add tweaks to your own build.  Most owners say it pairs better with the less de manding HD6XX series.

EC Super 7 (available used only) - Bassy and thicker. Darker sounding the most stuff here. Balance can vary though quite a bit depending upon tubes. Can mix and match 6SN7s for an almost infinite variety of textures, timbres, tonal balances. Great slam and microdynamics. Very good resolution, at least with the versions with the ElectraPrint transformers. S7’s have been modified for better clarity and less thickness.

Luxman P1u (available used only) - basically sounds like a ECZD lite. Slightly more veiled, slightly less fast, but just a euphonic in a no hassle solid-state package. The P1u sounds dated – it’s less technically competent than most other amps in list now. But again, how you can get that luxurious ECZD sound in a solid-state package?

Bryston BHA-1 - Delineated treble attacks, but actually works well with HD800. Neutral sound. Some reports of MOSFETS getting hot resulting in bass mud galore. Recommended if you live in a cool climate. Do not stack on top of anything else and make sure there is good circulation. This amp does not like heat. Good staging for solid-state compliments HD800. Flatter than the better amps, but if you want solid state, one of few choices.

DNA Sonnett 2 - Has the DNA house sound with inner warmth, intimacy, immediacy. Improvement in clarity and resolution over the Sonnett 1. Basically sounds like the Stratus but without the DHTs - that last bit of microdynamics, separation, and staging. HD800s out of the box work with Sonnett 2 without mods of any sort.

HDVD600 / 800 - I had my doubts, but a great match with HD800. A very refined sound (HD800 is smooth with this amp), but lacks the slam the better amps have. Balanced mode a must for staging, layering, separation, openness. Not an exceptional amp, but very solid choice considering price. I found the amp circuitry to impart its own sound which allows the benefit of using a variety of sources while maintaining synergy with the HD800. This can either be a good thing, or a bad thing. I believe the output impedance is ~50ohms which would explain a lot of things. Not a good amp to use with orthos.

Schiit Ragnarok – Best solid-state amp in headphonia and the only one I think is capable of competing with the great tube amps. Highly resolving and must be careful with source. With the right pieces in place, the smoothest sounding amp, solid-state or tube I have ever heard. And with solid-state cleanness, clarity, and tautness. I use the HD800s with “light” Anaxilus Mods with the Rag. Best solid-state amp for HD800 period.

ECP DSHA-1 - Solid-state but not solid-state sounding amp. Not tubey sounding, but has treble characteristics akin to tubes. Against the big boy amps, just a tiny notch below in terms of explosiveness, resolution, microdynamics, clarity. (Honestly, I don’t think most people would notice.) One of the best sounding solid-state solutions. Works well with Joe and John Grados too.

EC ZDSE - Euphonic sounding amp. Luxurious ride in a Mercedes. Slightly veiled when compared to the big boy stuff. Very good stage. Warm and euphonic. Ironically, treble is the sharpest (just sharp, not nasty) of all EC amps; but all other EC amps tend to sound "not bright". I've noticed most ZDSE owners have a thick copper cable with HD800. The older ZD (non-SEs) had better caps and were less veiled sounding. Keep the SE version at 12 ohms output impedance. It sounds best that way.

DNA Stratus - Slightly wet sound. Latest version and upgrades is an improvement all- around with better bass articulation, staging, blackness, etc. Intimate sounding and actually good with cheap Chinese tubes (my personal preference would be probably be the more solid-state sounding EML Mesh or Psvane Replica WR275, but many like the big bottle Shuguang 2A3s for a lusher presentati on). Works straight out of box with HD800, although with latest upgrades, more care must be taken with source. Beyers, TH900, D7000, and many other dynamics also work really well with the Stratus.

Cavalli LG – My favorite Cavalli amp. Only as good as the tubes used. HD800 sounded great with rare vintage Mullard CV-181s. I haven’t even begun to explore the tubes this amp can use. The LG has the Cavalli trademark smooth sound - very refined and resolving which suits the HD800 tendency toward dryness. Fantastic with Paradox Slants, HE-5, Abyss too.

EC BA – Neutral or a tag organic sounding amp with new Cinemag transformers. Best staging, layering, separation, openness of any of the amps here by far because of high-frequency AC heater stolen from outer space satellite military applications. Need to be careful of source. Sometimes not a forgiving amp, but choice of tubes makes a difference. Since KR PX-4 tubes are unreliable, unobtainable, or a rip-off, get a BA built for the 2A3 tube where there is a wider variety of great tubes at modest cost. Yes, you can do that – a 2A3 BA.

EC 4-45 - Best production amp to take advantage of the HD800s technical capabilities period. Take the BA and turn things up a notch in realism. Soundstage is super precise, three dimensional, deep, and open. Not forgiving of source and is neutral / lean. However, the 45 tube presents the sweetest treble ever. Advise using with R2R DAC. Avoid if you like artificial warmth - it's a 45 tube after all.

Apex Teton - If the Luxman and EC ZDSE is on the list, the Apex Teton (similar in presentation) is a no brainer. In most technicalities, Teton is superior to both. The problem is cost. Most notable weakness is a lack of fully extended tonal dynamic range and a more relaxed laid back tempo; but some might like that with the HD800. [Anax from Pete's Esoteric Transport]


OTHER MENTIONS:

Woo WA5, but the time you are done with cap upgrades, and the necessary x2 mega regulator tubes to avoid HD800s from sounding limp-dick, plus x2 driver tubes, plus x2 300B... you get the point. And honestly, it doesn't compete as well with the other big boy amps. But its sound is considerable lusher than any of the others. Keyword is lush, so certainly a consideration.

The two Bakoon amps also work well with HD800 from the current mode out jack with very nice tone with loss of ultimate technicalities; but too expensive / poor value unless you pay 50%-75% MSRP via a Massdrop.

Apex Teton is very good, but I need more serious head-time with this amp to say. It's an OTL amp and definitely has that OTL sound. I have conflicting reports from people on how resolving this amp is compared to the best, and need to hear it myself with known DAC and recordings to verify this aspect. Pyrates are getting their hands on this, but it will be some time. It is not cheap though.

I avoided mention any amps which gooified the HD800 because I feel HD800 gooification or not taking advantage of at least 70% of what the HD800 can technically do is just plain wrong. You are better off with an Audeze instead of gooifying the HD800. Amps like WA2 and Leben belong in this category.