I ran across some 5687, 5842+5687 & 5842+6080 SE amplifier projects documented on Stein Hsu's blog page. No activity since 2013, but among his 52 posts in 2013, there is a lot of other classic amplifier circuitry explored, mixed in with politics.
The 5687 and 6080 projects were what caught my attention. The jpg's with schematic commentary are in English. The rest of the discussions I needed to rely on Google Translate for, and it was good enough to read & understand.
The 2013 blog entries may or may not cover any new ground, but the 2011 cascode SE power amps appear to be his own developments, inspired by a Colin SE amp using one 5687, (standard two-stage cascade, rather than cascode).
I haven't found posts about his work...just in Google searches, so I'll share here.
2013 full blog Stein 大小聲: 2013
2011 5842+5687 Stein 大小聲: cascode 5687 Power Amp (1)
2011 5687+5687 cascode PA Stein 大小聲: cascode 5687 Power Amp (2)
2011 5842+6080(1/2) cascode PA Stein 大小聲: Cascode 6AS7 Power Amp
The 5687 and 6080 projects were what caught my attention. The jpg's with schematic commentary are in English. The rest of the discussions I needed to rely on Google Translate for, and it was good enough to read & understand.
The 2013 blog entries may or may not cover any new ground, but the 2011 cascode SE power amps appear to be his own developments, inspired by a Colin SE amp using one 5687, (standard two-stage cascade, rather than cascode).
I haven't found posts about his work...just in Google searches, so I'll share here.
2013 full blog Stein 大小聲: 2013
2011 5842+5687 Stein 大小聲: cascode 5687 Power Amp (1)
2011 5687+5687 cascode PA Stein 大小聲: cascode 5687 Power Amp (2)
2011 5842+6080(1/2) cascode PA Stein 大小聲: Cascode 6AS7 Power Amp