FLTWS
Headphoneus Supremus
Here's my 12AU7 inventory; (All acquired from Upscale)
2 Mullard M8136/CV4003
2 Amperex Medical 12AU7
2 Brimar CV4003
2 Radiotechnique 12AU7WAH
2 Gold Lion ECC82/B749
2 Cifte 12AU7
(Note: can also be use in Valhalla 2 with adapters)
I typically rotate tubes a couple times a year so with tubes its never a once and done for me. I like variety and to revisit equipment, including tubes. Over time performance can change, new equipment may be added / deleted, and I know from experience, how I feel about something today may change over the course, of say, a year.
To answer your question; with respect to the Gold Lions; a forward midrange is a coloration, the midrange pushed forward, too vivid, out of balance with the rest of the frequency range (to my way of hearing it with my musical genre of choice and the equipment I listen with, not necessarily the same for you with your equipment). But if you like an bold midrange with your preferred musical genre the Gold Lion might be the right tube for you. Keep in mind these differences are never day/night, unless the tube is defective or not performing to spec and always small, not order of magnitude stuff.
It's not just about the tube. It's also about the circuit it's used in and, even more importantly, to my way of hearing it, the transducer it's used with. I like the Cifte with my 1266 better than with my Utopia, the 1266 Phi doesn't mind the touch of brightness I hear with my Utopia and the Cifte. I prefer the Mullard's (or Brimar's) with my Utopia with their softer highs than the Cifte's. And on and on. And as a tube ages it's sound might alter. And a year down the road I may feel differently about the sound than today. How many times have you seen mag / web-zine reviewers re-visit a component after a 12 month period of living with it? Time changes everything.
For me the key is how the tube matches up with my different headphones. And now that I'm working on a return to 2 speaker stereo after 15 years of no in-room speakers, the matching of the tube sound with the speakers sound signature and my room acoustics may very well change my thoughts on the different sounds of these 12AU7's, and what I prefer with my headphones may not be the same with whatever speakers I choose, or maybe it will stay the same. I won't know for sure until I start rolling. The integrated amp I've settled on uses 12AU7's on the front end and while I haven't decided on what speaker to go with its possible that tube preferences with my HP's may not align the same way with whatever speakers I buy.
It would be nice if we could select a tube and be one and done. Unfortunately we don't all hear the same, (and not everybody wants to listen that hard to determine if they hear these very small differences). And there are so many other variables in the sound of the equipment chain and the transducers we use them with, the music we listen to most, and our expectations and bias's, You've just got to experiment a little for yourself after investigating others' impressions. And, if I had just one amp and one headphone it might be easier, but that's not in the nature of how I enjoy and engage with this hobby.
Think about what your rig sounds like to you and what you want more of less of. Check out the descriptions of different sound traits of 12AU7's on various sites like Brent Jesse, Lowtechelec, Viva Tubes, etc. just to name a few off the top of my head). You can also e-mail some tube dealers and get their thoughts on a tube with the equipment your going to use it with. Some may just tell you the most expensive are the best - again there's a learning curve here, not just about tube sounds but your dealer interaction as well. I had a dealer talk me out of the most expensive available of a different tube type he carried saying it might not be to my liking given what I had told him about my tastes in sound. And like has been said often, you can't make an omelet without cracking a few eggs. You have to buy and try.
There is nothing wrong with the sound of the Gold Lion's or the JJ's, it's all about personal preferences. I listen mostly to large scale classical, usually recorded with a dozen mics hung a few feet over the orchestra with more than needed spotlighting (in my opinion) and I hear a lot of the initial, immediate, sound. My preferred seating in the concert hall is front row, first balcony, near center where the mix of direct and reflected and co-mingled sound is very different. If you accept that the mics are your ears in a recording, then the general perspective in most multi-mic'd classical recordings (with or without the addition of ambience) is; I'm suspend over the orchestra looking down. Piano keyboards stretched from 25 to 35 feet from the first violins all the way across to the cellos is always an epic fail to my ears. Nothing like I experience in the concert hall as to image size, positioning and sound stage perspective. Even from the orchestra pit its not the same perspective on the orchestra as being suspended over head. At the Kimmel in Philadelphia they have seating above and behind the orchestra, having the the violins right and cellos left completely screwed with my head, I could not un-do 5 decades of going live and listening from in front of the orchestra. I can't tell you the number of times I've visited high-end audio stores who had the left and right channels reversed and noticed nothing wrong when I gave them some orchestral music to play, LOL! I suspect classical was not their chosen genre.
I try and find a happy medium for myself with respect to top to bottom sound, imaging, etc, when working with my rigs. Something that enhances the strengths and mitigates the short comings with the music I listen to most, the equipment I have, and what I think sounds best. Other genres may have different recording issues to deal with, maybe in smaller acoustic settings, studios, live location recording, etc., that present other challenges to the engineers.
