I've got some px-300b and some treasures on their way, I'll see if I can help with a small review soon. They'll be compared in the driver section of my JAS Audio Array 2.1.
Initial thoughts when comparing the GL px300b to a Shuguang 300bc is that the GL is more opened and detailed, more lively tube that is less veiled but has that Russian metalic sound. I'm going to swap out some resistors to see if it it's the metal films, due to the more revieling nature of the GL's. The Shuguangs seem well damped(short decay) and more tubey, they present with good body and have that sweetness or sparkle on top, a darker sounding tube, less fatiguing in my system.
I've not heard any other 300b's to reference these to, so It is a direct comparison.
I to had hoped for a good review on the px-300b's but couldn't find one.
Maybe someone more experience than I will post.
