A 50VA power toroidal core is DC saturated by the Pleiades BD139 power music amplifier operating at 50-70mA

See previous post:
https://euroelectron.blogspot.com/2019/06/winding-toroidal-output-transformer-for.html


It is funny. Just one transistor amplifier operating in class A (electrons flowing all the time) sounding so loud and nice at 250mW power out yet a 50VA core used in output transformer is DC saturated which ruins the bass. More than 1/2 KG mass of iron is needed. Operating point is 10 to12 V, 50 to70 mA.


Or rewinding a speaker from 4Ω to say 60Ω and use no output trasformer. There would be loss of power efficiency by the DC quiescent current heating the voice coil but it can sound great. Or many speakers is series.


Or an EI transformer with air gap.


Or a toroidal core with air gap.


Etc