I went around the house trying to my bargain Electro Harmonix 300B so I could do a direct comparison. I wasn't able to find them. I figure having one reference point for direct comparison would help me more accurately triangulate with my memory of other 300B tubes I've heard on the Studio B. For now, it's all based on memory. You can call me full of shit, but I think you guys know by now that I have a pretty good memory of how stuff sounds. The is the third coming of the Western Electric 300B. There was a second coming sometime in the 2000s. I'm not sure exactly when. Please correct me if I am wrong. I believe Craig Uthus at Eddie Current / Moth Audio may have had a pair of Western Electric 300Bs, but ended up not having them and then regretting it. Or maybe not because Craig doesn't listen to tubes. He sells the good tubes that he gets to customers. I viewed with skepticism this third coming of the Western Electric 300B. It's supposed to be the same factory, same machining, same processes, and I would assuming as similar materials as possible to what was available in the 1940s. I was going to stay skeptical under I actually heard one. My impressions on this third coming of the Western Electric 300B is that yup, it's a 300B. I've never heard a vintage 300B before and I'm pretty sure if I did, it would probably be well used and not necessarily representative of how it's supposed to sound.** Listening to this WE 300B, it does seem to all make sense. This is the source, the ideal, of what all the other new production 300Bs strive to shoot for. Listening was through the Eddie Current Studio B, via Grado RS1X (Gerod Earpads from Amazon), Audeze LCD-X (RD Modded), and Frugel-horn XLs with Fostex FE167NS driver. The Studio B is an output transformer coupled SET. It takes a small amount of feedback (~1.5db) from the tertiary winding of the OPT. I have early prototypes of the Studio B, but this is this first time I've heard the production version. I think that the production version ended up with just a hair less feedback than the prototype. The feedback helps tighten up the bass. Bass from SET amps without feedback always sounds rounded or even murky to some extent. The feedback also reigns in some of that 300B characteristic: bloomy lower mids (I prefer to say that this includes upper bass too, but this is a matter of semantics) and rolled highs. If you ask audiophiles, some will say that the 300B is the best thing ever. Others may say yuck. I'm kind of in the latter group because I'm a type 45 guy. The problem is that the 45 is super low power, having one-quarter the power of the 300B. Anyway, what I'm trying to get at is the EC Studio B doesn't have an overt 300B sound. It splits the difference enough for me to really like it. Besides, I think the Studio B is Craig's overall best, and probably last amp design, at least for his amps that aren't custom or don't use unobtanium parts. I am assuming because of the design, you can drop whatever 300B into the Studio B, and the amp will still sound good. This isn't true for many 300B amps I've heard. Some are very tube dependent. Because of this, when I dropped the Western Electric 300B* into the Studio B, flipped the on switch up, and listened via whatever headphone or my speakers, the clouds did not part, rays of light did not shine upon me, angels did not sing, I was not touched by the hand of God. However... I did say to myself: ahh, so this is what it's supposed to be like. *I had let the tubes run overnight. Manufacturer says 100 hours burn-in. While I do think burn in is necessary because tubes have mechanical parts that need to settle from heat, expansion, contraction, etc, I don't think it takes 100 hours. **The fact is, there are so many tubes on their last legs out there that we don't really know. So when somebody claims a particular unobtanium Wolf-Penis Tube is super-awesome, I don't believe them. Oftentimes, this unobtanium is used to shit and is soft sounding and distorted, but the person actually loves the sound this way.