The bad news: my #1 band had to cancel our Friday gig due to death in our singer's family. The good news: I got extra quality time A/B-ing my new Read Purity with my trusty old Alembic F2B. I also threw in a quick A/B/C with my Ampeg SVP-Pro... but that's a hairy old coconut compared with two mangoes (I mean that in a good way). Anyway, here's my test setup: MTD 535 strung with Hi Beams, onboard EQ kept flat. Stewart World 2.1 for power, and Bergantino HT115 to move air. Result: I am very blown away by the Purity... it is aptly named. I'm not saying the Purity blows away the F2B, but it is every bit as clear if not clearer, has much better tone shaping capability (see below), and more features (mute, master volume, tuner out, FX loop, hi/lo impedance switch for the input, and a DI with ground lift and level control). When I first started A/Bing (both set flat), the midrange clarity of the Purity jumped out. The Alembic sounded a little blurry. With the Purity, I could tell that the B string on my 535 was starting to go dead, just a leetle. I reduced bass and mids on my F2B and that cleared up the blurriness some, but even so the Read still has a certain extra clarity to it. At first I was disappointed in the bright switch of the Purity. It was nice, but had less boost and lacked the presence and "shimmer" of the F2B bright switch, which seems to be voiced higher (at 10k or so?). But then I realized the tweeter on my Berg was rolled way back because I typically use it for extra girth underneath my HT310. I goosed the tweeter a bit (still below flat) and the Read acquired that lovely tube shimmer whereas the Alembic got too bright. I'm sure the bright switch on the Alembic was designed for tweeterless cabinets. I still wish the Read bright switch was voiced a smidge higher but that's a very minor nitpick. I don't exactly know how to define clarity (except maybe "flat and not blurry"), but the Read has it. The Read also has an EQ defeat switch (all EQ except Emphasis and Bright is bypassed), and clarity actually does seem to improve when this switch is engaged. Note: this is not an "all else being equal" comparison between the F2B and Purity because of one detail: tubes. Jack is incredibly picky about his "standard" selection of tubes, and he also offers upgrades (Telefunken, cryogenically treated varieties, etc). My Purity has two of the "standard" tubes. I don't recall what's in my F2B; I just went with some inexpensive ones my tube amp tech recommended (less than $25 for two). So, it's very possible that a tube upgrade would increase the clarity of my F2B. (Also, I'm using the low impedance input setting on the Read... seems to sound a smidge better with my 535 but I can't explain how or why). Even if clarity were equal, I'll still keep my Purity. Reason? The EQ section! Now, I've spent a lot of time using the Read with EQ bypassed and Emphasis off, and it's absolutely marvelous. No guesswork involved about where "flat" is. But this is at home in my basement, sometimes soloed, sometimes playing along with RHCP's "Californication". But at gigs, all bets are off: the real test will be dealing with eccentric acoustics. As noted I haven't gig-tested my Purity (got 2 gigs next Saturday, one outdoors and one indoors, and will report back then), but I can already tell that I'm going to be happier with the Purity. IMO the one weakness of the F2B is lack of tone shaping in the mids. The interactive tone controls can make wide sweeping changes, but if you need precision, forget about it. Now the Read isn't exactly a 31-band graphic (!) but it's really nice to have two mid controls and the Emphasis knob. The Low Mid knob is perfectly named... my guess is it's around 180 or 200 Hz; it gives really low growl and could be called the Phat knob. The High Mid IMO is more of a Mid Mid (600Hz, maybe?) but it's great for adding or removing chunkiness. Finally: the manual says that the Emphasis knob "allows you to boost a broad band of midrange and upper frequencies in order to cut through a loud mix, or to warm up the tone of a mid-shy instrument". I can't tell exactly how it works, but it does work as advertised! I've usually left it off here at home with my 535 (certainly no lack of mids with this bass) but it does sound cool and I can see how it would be very useful, especially in boomy rooms. Overall: the individual EQ controls have moderate but not radical cut and boost, but when used together, radical changes in tone can be achieved. Oh... the Read doesn't seem to get very dirty. I cranked gain and lowered master and didn't hear much overdrive. But that's fine, actually! I told Jack that I wanted cleanliness from my Purity (for dirt I'll use a BDDI or RBI) and he selected the tubes accordingly. Even so, I plan to find a higher output bass (or jack up the volume in my 535 pre) and will report back what happens. Final notes: construction of the Read is top notch... sturdy jacks and controls. It's deeper and heavier than my other preamps, even the SVP-Pro, but I don't care, I got class H power! The look is basic but functional... very nice logo. I prefer black faceplates on rack gear but so what, the Purity is prettier than my ancient F2B that has black faceplate and big red knobs and light blue rack ears. Whew, I didn't intend to be so wordy but what the heck. In conclusion: I've loved my Alembic for many years, and with the Purity I was, at minimum, hoping for the clarity and booty of the Alembic but with better tone shaping capability. I seem to have gotten that and more. Full disclosure: I have auditioned other nice tube preamps such as Aguilar and Demeter, but have never owned those, or even tried the Kern, so I cannot offer any opinion on how the Purity would compare to them. But the Alembic is a damn good pre so I feel this review is valid.