November 2015 i purchased a pair of Elrog 300b’s for my Lampizator Golden Gate dac. i used them for 30 days on the 300b setting and loved how they sounded. then one of them got weak. i called Gary at tubes USA where i bought them and a week later he sent me a replacement pair. feedback to me from Gary who was told directly from Elrog, instructed me to use the 101d/45 setting on my Lampi GG going forward.
i installed the replacement Elrog 300b’s in mid-January of this year, 11 months ago and listen for 3-5 hours a day to them since then without any issue at all. still going strong.
I preferred them to Psvane 101d WE replicas, Psvane 300b WE replicas, and a number of NOS 45’s......all of which I still own but have not used since I installed the Elrogs. and yes, they are a cut above those others to my ears.
very happy with the outstanding performance and reliability since then and would highly recommend them assuming you get good advice on the context of how they are used.