Be warned, weary traveler, as you enter the hollowed halls (hallowed?…probably not) of my mind, you risk your sanity. Journey forward at your own peril into the depths of one mans opinions on the OCD based on his own first-hand experience... TL;DR (Too Long, Don’t Read [the rest] ) - They can all be dialed in to sound about the same or similar. While the audience will never know, the player will interact with each version a bit differently. The feel and/or nuances in how they sound is what sets them apart and the different versions tend to push the same amp a little differently (I think this is based on how the tone stack is eq’d differently in each version and/or other various tweaks he did.) They push differently enough that the amp will respond/sound a little different for each, assuming a tube amp, edge of breakup. I’ve included below two really good OCD videos from ToneJunkie and That Pedal Show that hi-lite some great stuff about the various versions, if your into deep diving this stuff. Also, a small list of budget alternatives at the end which I have compared to the OCD’s, one being quite the surprise. — The Details — I have been able to try and compare in person a 1.2, 1.3, 1.4, 1.6 all on the same amp. At separate times, I have compared multiple 1.7s and 2.0s including the Ge version, but on various in-store amps. The amp used for the “in person” testing is a Mesa Boogie California Tweed. While not exactly, its similar in sound to a ’59 Bassman LTD Reissue, the amp I owned prior (stage volumes may tell a different tale) Here are my thoughts on the pedal in least favorite to most favorite order. I will say off the bat I am not a fan of the 1.7s as they have always sounded too bright/brash for my tastes - perhaps too healthy a dose of the upper mids. The 2.0s seem to take the brightness up a notch (attributed to the 2.0 buffer per Dan in TPS video) while reducing the mids a bit. If I had to pick a current production OCD, it would be the OCD-Ge. I had one and willingly parted with it, so its more of a “I can get by with it” mindset than anything. There are plenty of MIAB pedals out there that do as good of or better job than the current production OCDs, depending on player preference. The v1.3 is my next least favorite as it has the most mids of any OCD I have heard. Its a good sound, but I am not a fan of mids heavy pedals (TS and the like) unless I need that for a specific sound - generally speaking, mids push is not my kinda sound. Having said that, if mids is your thing, the v1.3 is hard to beat and it pushes an amp nicely. Side Note: The Fulltone Robin Trower Overdrive tends to sound like a 1.3 OCD when pushed with humbuckers. Using single coils, it settles back into a fulldrive or thicker tube screamer type of sound - very Robin Trower sounding. The RTO is definitely its own circuit, but if you like a mids-flavored OCD and use humbuckers, it could get you there, but for about the same price as the 1.3 version of OCD. The only real benefit is being able to roll back volume into Fulldrive/TS sounds, where I think the OCD cleans up much more than the RTO. v1.4 is next and while I like this version, I like two others more. This sounds a hair more compressed than my two favorites and for rhythm, chords, etc its great, but the notes don’t jump out for me like the other two. This also may have a bit more mids that my favorites but definitely less mids than the v1.3. This is probably the most widely available used version, next to the 1.7s, but make sure you get it with the circuit board that says 1.4 and not 1.7. The serials are roughly 16100 - 70000, roughly. v1.5s start around 70K, but not clear exactly where. Side Note: v1.4 added a germanium diode to the circuit that 1.1-1.3 did not have (at least I don’t think it had them, but the goop makes it hard to know.) As far as I can tell, this diode came and went in v1.4 as its missing (jumper-ed) on the 1.6 boards (a 1.4 board, but hand marked 1.6 in the case.) The v1.7 boards do not have a place for this diode, presumably replaced by a trace on the board instead. This diode is why I personally think it is a tad more compressed than others, including my two favorites. v1.6 is my second favorite - to me it sounds like a marshal amp about to explode, almost Van Halen’ish kinda sound. Notes jump and bounce as you hit them - probably my favorite of them all for leads, for that reason. Its has this bright edge to it that is not harsh like the 1.7s - I personally think he should have stopped here instead of doing 1.7 but what do I know. The v1.6 is built on v1.4 boards, with a jumper where the diode is supposed to be. Serials are roughly in the 80K range. v1.2 is my favorite. Its not as bright as the 1.6 and notes do not jump quite as easily, but the way it pushes the amp is just awesome. It sounds closer to the 1.6 moreso than any other version, but its eq is a bit different. There is nothing harsh about this pedal and it just makes the amp “more" without adding as much of its own character to the sound as other OCDs seem to including the 1.6. It is probably the flattest EQ of all the OCDs that I have personally heard. Side Note: The v1.2 board is similar to v1.3 but different than v1.4. I think major board/circuit changes happened for 1.4, 1.7, 2.0. In between, the tweaks seem to be minor and swapping of various values/parts. Budget Alternatives: Hardwire SC-2 Valve Distortion - Good MIAB pedal that gives the OCD a run for its money Mooer Hustle Drive. I think the original version of this was based on the early OCDs, probably the 1.4. Marshall GV-2 with Joe Simon Guvnor V1 Mod - the modded version of this pedal is killer. It has a 4-band eq that can be used to eq the pedal to sound like/close to any version of the OCD. Joe Simon Mod: It sounds exactly like a Marshall The Guv’nor v1 pedal when eq’d accordingly. This modded pedal surprised me the most, given how so-so GV2 sounds stock. I hope my madness helps some poor soul who has chosen to travel that old OCD road….