I currently have an unmarked 12bh7 valve in the line stage of my Croft 25R (which was modded by Glenn to better drive a low impedance s/s power amp) and would like to try a 'better' version of this particular valve.
I cannot find much info on the web about the relative merits/sound quality of different versions of this particular valve and wondered if anyone here can offer any thoughts/guidance.
There are a number of different versions of a 17mm Brimar 12bh7 currently on ebay being offered by the same seller with different prices/construction/codes etc but unfortunately, the seller was unable to offer any explanation of the differences between them. Does anyone have any experience of Brimar 12bh7's....?
Thanks for any help/advice.
John