I’m finding that over time, I’m having fewer words to say. Probably the result of the heptagon spider charts, brain damage, old age, or crankiness from running a forum. So I’ve asked @Hands to help with me this. This guide is really his effort with a few notes from me where I could fill in the blanks. I’ve also removed some of the more damning comments made by @Hands to make this guide palatable to everyone. This is an evolving document. Oh, and I forgot: Hi Jude! Jude is an avid SuperBAF reader. He will deny it, but he loves reading this site to get good quality information. IN NO PARTICULAR ORDER Schiit Valhalla 2 (OTL White Cathode Follower) Neutral, fast, clean, detailed, good staging, good air. A bit lean and lacking in macro-dynamics and slam found in the TOTL tube amps. Can be a bit dry sounding and have a sandy quality to the upper registers. Warmed up tubes, laid-back sounding tubes, and a good source (R2R / 2R) can alleviate these characteristics, but it never totally goes away. The Valhalla 2 is good introductory tube amp that pairs well with higher impedance headphones and efficient orthos, but may still be too solid-state sounding for some people. Because of its topology, rolling tubes doesn’t affect the sound as much as it would on a top-notch phonostage. In other words, don’t spend a lot on tubes - buy a better amp instead. Measurements: http://www.superbestaudiofriends.org/index.php?threads/schiit-valhalla-2-measurements.2820/ Laconic Night Blues Mini (Transformer Output Push Pull) Worth it if you can find a native 120V version, or use a step down transformer. You’ll need to smuggle it in from Russia. Best described as a Super 7 junior. Like the Super 7, The NBM is transformer coupled. Also fairly neutral like the Valhalla 2, but more dynamic, sweeter, lusher, smoother, and more liquid. The high end is fantastic on this amp. Good speed, resolution, and staging. Loses out a little bit in the bass region which is slightly blurry. The volume pot is cheap and may not track well. Moving up to the TOTL tube amps will gain you further dynamics and refinement across the board, but this one of the best sounding amps for about $250. The value perspective is insane. Measurements: http://www.superbestaudiofriends.org/index.php?threads/microzotl-2-0-measurements.1724/#post-43543 MicroZOTL w/ LPSU (ZOTL Push Pull) Sounds pretty decent with good tone and timbre – harmonically rich sound. Main issues are mushy, bloomy, ill-defined bass and a flat 2D stage. Has a full and powerful sound, yet is flat sounding (think a commonly loud CD these days - powerful but lacking in dynamic depth). With extended listens, an underlying prickly sound in the upper registers becomes apparent. Tube rolling helps a bit, but two pairs of quality 6SN7 and 12A_7 tubes don’t come cheap these days. The dozen or more screws on the top plate discourage tube rolling. Where the MicroZOTL excels is flexibility, being able to power moderately inefficient orthos, highly efficient speakers, and traditional dynamic headphones. Measurements: http://www.superbestaudiofriends.org/index.php?threads/microzotl-2-0-measurements.1724/ Feliks Elise (OTL SET) Mostly neutral, fast, resolving, and has good staging and layering abilities. Has a bit of softness and a good amount of bloom to the sound that can be addressed with the right tubes – to a limited extent. The Elise is the most “wet” sounding amp in this list. The main issue is a noticeable roll-off in the lowest octave with some headphones, and thus it can suffer from a lack of slam, dynamics, and sense of foundation. The bass is more rounded, murkier, and bloomier than the NBM or Valhalla 2. This is not unexpected of an OTL with 45 ohm output impedance. Responds well to tube rolling, but don’t think turning it into a Christmas tree of glowing filaments is going to make this amp competitive with TOTL tube amps. (@Hands opines that this amp is a tier below the NBM. @Marvey opines that the Elise is a tier higher, but different sounding). Tube rolling notes:http://www.superbestaudiofriends.or...se-tube-amp-review-not.2260/page-9#post-59474 Marv totally flips out and warns against the sport of extreme tube rolling: http://www.superbestaudiofriends.or...se-tube-amp-review-not.2260/page-3#post-57578 Bottlehead Crack (OTL SET - DIY) Needs speedball. Lots of modding options. Worth pursuing if you want a warm, dynamic, bassy, and fun sound that will give you shits-and-giggles. Pop in a Tung Sol 5998, a fairly neutral 12AU7 tube, good quality output caps, a PSU choke, and a better volume pot, and it's competitive and worth considering over some amps on this list. Once you "max" it out with mods, it only really suffers from a close-up small stage, lack of bass definition and tautness, and lack of ultimate resolution. Fully pimped out, the Crack is worth consideration over the Elise, MicroZOTL, Lyr 2, Valhalla 2. Crack resources here: http://www.superbestaudiofriends.org/index.php?threads/bottlehead-crack.120/ Schiit Lyr 2 (Hybrid) Powerful, thick, warm, cozy, and intimate. The stage is small and close up. More dynamic and full sounding than Valhalla 2, but somehow less emotionally engaging. Less nuanced and articulate from top to bottom, especially on the lower end. Well worth considering if you like warmth and slam and cheap. Schiit Vali 2 (Hybrid) The Vali 2 is tonally laid back. A step up from Magni 2 in terms of musical involvement stemming from better microdynamics and resolution. Might actually equal or exceed Lyr 2 in these regards, but the Lyr 2 is still superior in macrodynamics and slam. The bass is slightly soft like the NBM. Having only one tube to roll means tube rolling can be done at a 50% discount (or more because we don’t have to obsess about matched tubes.) This is Schiit's answer to people who bitch that Schiit amps are too aggressive sounding. Measurements: http://www.superbestaudiofriends.org/index.php?threads/schiit-vali-2-measurements.804/ Schiit Mjolnir 2 (Hybrid Circlotron Output) Sounds more like a souped-up Valhalla 2 combined with good traits of the Lyr 2. Very dynamic and powerful sounding, sometimes in ways we've never before from a headphone amp. Maybe the slightest U-shape to the signature, but tastefully done. Rather articulate, resolving, and micro-dynamically nuanced with the right tubes, or it can be rather fun with other tubes (or a mix in between). The only way it falls short from TOTL tube amps is a lack of stage depth and expansiveness, which hurts 3D layering and separation. Can bit a bit etched or dry sounding in the upper registers depending upon tubes, but a marked improvement from the Mjolnir 1. An extremely solid choice under $1K. Can power almost anything, but don't do what Marv did with the Mjolnir 1 and power speakers with it. ECP Torpedo III (Hybrid Parafeed Transformer Output) This is a DIY amp, so opinions will vary based on tubes, caps, transformers, current sources, and other mods and tweaks. It's comfortable around TOTL tube amps. A good build will have good staging and layering, albeit a bit more condensed than the best amps. Slightly lush, slightly euphonic, and slightly bloomy. Maybe not quite as dynamic and hard hitting as some amps, but very resolving. Very even and very solid in the bass and the mids. Some builds lacked treble refinement with a brittle high-end, but it’s possible to tweak around this. These nitpicks are relative to TOTL tube amps. As we move up, we get tougher with criticisms. A maxed out Torpedo III is in a higher tier compared to all the amps above. Torpedo III resources: http://www.superbestaudiofriends.org/index.php?threads/ecp-torpedo-iii-indexed-in-first-post.434/ Eddie CurrentSuper 7 (Transformer Coupled SET – OOP) Mk1 with the EI core output transformers has a thicker, more powerful, more organic sound. The Mk2 with the double C-cores is more neutral / brighter, smoother, but with less open and airy stage. Both versions are responsive to tube rolling. Replacing the interstage and electrolytic feedback caps with boutique parts will push the performance up to a high ceiling. The sense of dynamics, slam, and overall bass quality outperforms almost everything on this list. Staging can be wonderfully dimensional, layered, and airy. Tone and timbre is spot on. This is on the level where TOTL tube amps offer only extremely diminishing returns. Once a bastard child going for less than $1000 in the used market, used prices have since recovered and units are now hard to find. Sound quality depends highly on tubes. We can mix and match tubes in the three pairs of the output section to tailor the sound to our preferences. Be prepared to shell out money for 7 NOS 6SN7s, which aren’t cheap anymore.