Here's the link to Edcor... there are many choices available, depends what you want to spend. I used the GXSE15-6-5K for my SSE... they were a great match for my Klipsch speakers...
Edcor Single Ended OPT
The One Electron xfmrs you are looking at don't have UL taps, so if you're planning on using UL with your amp...
Hey Denny that's so much ... Ok disregard my last message ..
I misread and I see that edcor was for the SSE
Not the 300b SE