Koss ESP950 (arrived broken. Sent back. Never refunded. I have been SCAMMED by headfi'er BoogieWoogie)
I would be interested in trying: Stax 4070
Had (or tried):
Stax SR-007 Mk1 (heard at least 8) -> Most special oyster in the headphone world. Unfortunately, several variations due to quality control issues. At their best, they have unparalled layering, clarity, exceptional deep bass and don't sound dark. 7xxxx S/N have bigger chances to be much better than other production lots. The right midrange presence is the most difficult thing to achieve with source/amp matching, even with the best specimen.
Stax SR-009: You put a great, analogue sounding source with the SR-009 and the sound is magical. You put a great, analogue sounding source behind the SR-007, and someone will tell you that your amp is the problem, and/or your source is not enough.
Stax SR-X Mk3 Pro (2x) -> great midrange, lean midbass, but extremely rumbling and powerful deep bass; small soundstage, extremely discomfortable. Easy to be made strident. Extremely source-dependant.
Stax Gamma Pro -> Princess of the loudness war
Stax 404/Spritzer modded -> I only remember it was sweaty
Stax SRS001 Mk2 with Audiocats-modded amp -> fantastic mods for an otherwise poor amp
Stax SR-003 -> miniature sized SR-009. Looses in bass depth, soundstage, overall detail, while has an edge in intimacy and overall smoothness.
Stax SR-003 Mk2 (and SR-002) -> how to destroy your roots for a "brighter" future
Koss ESP950 -> transistor radio made famous
AKG K1000 -> purest sounding earphone in the world.
Audio-Technica AD2000 -> live equalizer. Bass and treble are never out of place. Midrange can be, though.
Tamboti Thunderpants -> super aggressive midrange, small soundstage, smooth highs, fast, tight bass
LCD2 Rev1 -> unnatural, clinical, strong deep bass, empty midrange... sounds like it's making music for a different species
LCD2 Rev2 -> in opposition to other people's impressions, the Rev2 I got was a darker than that Rev1. Great headphone if it retailed 200 Euro new.
Yamaha HP3 -> a bullet must have killed the midrange frequencies. Otherwise super tight/deep bass, super comfortable, very fast if properly damped
NAD RP18 -> darkish... sloppish, also
Sennheiser HD650 -> thick; thick and sibilant when badly amped; I wish to hear it in a proper, balanced setup
Sennheiser HD580 -> the bass goes its own way, constantly missing the timing of the music. Bloated. This is with CKKIII, regardless of the source and cables
Sennheiser HD250 Linear I -> hole in the midrange, fast, spikey treble
Sennheiser HD250 Linear II -> hole in the midrange, fast, more spikey treble, strong deep bass
Sennheiser HD800 (only loaned) -> super fast, hypertextured, wrinkled bass; distant, hollow midrange, spikey treble; huge soundstage
AKG K501 (repeatedly loaned) -> beautiful midrange, not very resolving, slightly sibilant, average soundstage and bass depth
Apuresound Etymotic ER4P/S -> fantastic but aggressive, not really "warm", the bass is as tight as a stone, in general a lean, aggressive, addictive sound without any hints of sibilance (the P), or with some hints of sibilance (the S).
Etymotic ER4P/S -> more linear midrange, but less emotionally addicting than the Apuresound version, easier to drive (the Apuresound P requires higher volume, go figure). The stock S is very sibilant
Etymotic HF-5 -> inferior to normal Etys, the bass reaches less deep; less refined across the notes; exceptional for home use with the Etymotic PtoS adapter, especially with a warm/darkish signal path behind
Westone 3 -> big sound, lovely low level details (echoes), the balance is weirdly u-shaped so that the midrange lacks some energy. Upper bass is full, treble is extended
Westone UM3X -> warm as a womb could be. With triflanges it can also sound airy, otherwise suffocating
JH13 -> transparent, neutral, small, polite midrange, transparent. Not a good idea for your regular DAP
Triple.fi 10 Pro -> big bass, big soundstage, overpowering bass, ghastly midrange, extended treble
HifiMan RE272, RE262, RE252, RE0 -> the RE272 and RE262 are very fine sounding, lifelike, if you can stand the discomfort
Yuin OK1, OK2, OK3, PK1, PK2, G1 -> I will remember the PK1 as the one with a meaningful personality. The others are just cold.
Koss A250, KSC75
Grado SR60 (and I have heard RS1i, PS1000)
Headphone Amp Inventory:
MacIntosh MHA100 (on loan)
Stax SRM-727A with KGSSHV mods
KG Megatron (in progress...)
Stax SRM-717, Stax SRM-001 with SFC++ mods (by Audiocats, Vitq caps), Stax SRM-1 Mk2 Pro, SRM-Xh
MisterX Mini^3 and less interesting portable amps.
Subjective ranking that may change across time:
Lector Digicode S192
Weiliang Dual AKM4399 DAC with Museatex modifications
Museatex Bitstream Plus (Upgraded)
Museatex DA-44 Plus (Upgraded)
April Music Eximus DP-1
Assemblage DAC 2.7, DAC 3.0
Metrum Octave Mk2
Audio Note DAC2.0
Antelope Zodiac Gold + Voltikus
Halide DAC HD
Other stuff: Museatex Bitstream (stock is useless), Arcam Rpac (impressively decent), Yulong DAH1 (better than your average mp3 player), AMB Gamma 1 (not better than your average mp3 player), HiFiMan HM602 (too bulky to make sense, but analog sounding!!), various portables, Imods. I loved the Kenwood HD20GA7 mp3 player, it started my Head-fi journey.
Would like to try: Phasure NOS, TotalDAC
Di Marzio interconnects
Other Audio Equipment:
Mordaunt Short Performance 6 Ltd speakers
Luxman L-58A integrated amplifier
Neumann KH-120A: lovely monitors, balanced, detailed, but still not smooth enough
Adam A5x: silly, blurry, bassy, unacceptable lack of imaging. Overpriced.
Captain Beefheart, Frank Zappa, Tim Buckley, Robert Wyatt, Gong, Faust, Can, Amon Duul II, Neu, Uludag, Red Crayola, The Velvet Underground, The United States of America, Jefferson Airplane, The Moody Blues, Silver Apples, Grateful Dead, Pink Floyd, Roxy Music, Public Image Ltd, Traffic, Royal Trux, Television, Pere Ubu, Talking Heads, John Cale, Lou Reed, Nico, Neil Young, Bob Dylan, Ry Cooder, Van Morrison, John Fahey, Leonard Cohen, Cat Stevens, Roy Harper, Yes, Area, Van Der Graaf Generator, Henry Cow, Art Bears, This Heat, Camberwell Now, Thinking Plague, Sonic Youth, Brian Eno, David Bowie, Cocteau Twins, Buggles, Jimi Hendrix, Pixies, Husker Du, Violent Femmes, Foetus, Mr. Bungle, Phish, Nick Drake, Jeff Buckley, Lydia Lunch, Franco Battiato, Mercury Rev, Red House Painters, Lycia, Morphine, Solex, Peter Gabriel, Steven Ridgway, XTC
Charles Mingus, Carla Bley, Sun Ra, John Coltrane, Cecil Taylor, Miles Davis, Art Ensemble of Chicago, Albert Ayler, Ornette Coleman, Thelonious Monk, David Holland, Dexter Gordon, Eric Dolphy, Alice Coltrane, Paroah Sanders, Zu, Paolo Conte