12au7 tube?

Tube rolling seems to be the correct way to begin fine tuning the sound. Cables and power cords should come next, I would think.

I know that a lot of the older 12au7’s can sound very different. Some I’ve found to be very bright, other thin sounding. Others too soft, others lacking in the highs, other with too much highs or lacking in deep bass etc.  So I’ve heard many different sounds from vintage 12au7’s but what I like about them above current production is that I feel vintage tubes are more transparent and flesh out and breathe the music through better. I will say I’ve heard some vintage tubes that have been veiled and aren’t so transparent and not as good as I expected and don’t like them but I will honestly say I haven’t ever heard a new or current production tube sound better, in terms of transparency and fleshing out the musicality better than some of the well respected and reputable vintage 12au7’s.  I think the only way we will see some current production tubes outperforming these classic vintage tubes will be if a company takes on the process of building high quality tubes as they did years ago. And as we see that happening today, those tubes from these companies usually cost $$$.  My friend paid a couple of thousand of dollars for a pair of Elrog 300b tubes. 

Elrog 300b = $3,500 pair

I  spent $450 for very close tolerance within 2% medical grade Telefunken with the red tips worth every penny and last for years.

if you want a very good modern tube -12au7 

at APIs audio  Rays select tubes  hand picked closely matched made to a very high standard and a full 1 year warranty for-under $200 . I have the Rays big bulb 6SN7 

complementing the Tele 12AU7 in my LSA preamp is sounds very good .

Rays select 12AU7  

https://apos.audio/collections/top-sellers/products/apos-ray-tube-12au7