09-12-2011, 07:30 PM
http://mike.saunby.net/2010/07/kt44-push...ifier.html
http://mike.wepoco.com/Home/retro-geeker...-Amplifier
ra is completely dependent on the actual operating point set in a class b or ab1 or various modes. I usually just treat the figure given for audio use single ended and consider that as "to centre tap" and you aren't far off IMHO. Lots and lots of manufacturers and designers got it completely wrong as well. Apparently triode strapped they are identical to the PX25.
There is no reason why pretty much any triode or above can't be used for an audio output stage. I built a thing way back using 18 EF80's (had a box full of them, a chassis from a relay era bandit and a spare output transformer) Chucked out about 10 watts of rather mean sounding guitar (by ear), was probably miles off anything like sensible operating conditions !
http://mike.wepoco.com/Home/retro-geeker...-Amplifier
ra is completely dependent on the actual operating point set in a class b or ab1 or various modes. I usually just treat the figure given for audio use single ended and consider that as "to centre tap" and you aren't far off IMHO. Lots and lots of manufacturers and designers got it completely wrong as well. Apparently triode strapped they are identical to the PX25.
There is no reason why pretty much any triode or above can't be used for an audio output stage. I built a thing way back using 18 EF80's (had a box full of them, a chassis from a relay era bandit and a spare output transformer) Chucked out about 10 watts of rather mean sounding guitar (by ear), was probably miles off anything like sensible operating conditions !
