คัดลอกมาจาก Web site ๆ นึง..
Here is some of my recommendation for 3/3.5k Output for 300B: That is the most common impedance I tested. The list on top is my favorites but not indicate the best for you! You have to refer your budget and your taste as well.
Tango X3.5S: Double C-core Silicon steel core. Excellent micro dynamic, Great bass extend, Still keep a magical med. and high frequency details and clean. I love it¡¦s natural sound and very balance performance! That is the biggest and heaviest. Also, most expansive one! Made in Japan
Tango NY3.5S: EI core 78% Nickel (new production only got 40% nickel contents). It has Excellent mid. And high frequency details; Very solid and smooth sound. Seen unlimited sound between each node; perfectly if you love violin or female voice. It has a bit soft on bass but still performance excellent. Made in Japan.
Tamura F5002: 3.0k EI core Permalloy. Nearly same performance as Tango NY3.5S; But even more smooth

liquid. The bass is a bit softer than NY. That is the only point I few not so perfect. If it can have better bass extend and amount, I would choose this! Made in Japan.