Toy13 300B Amplifier DIY Record....1

Design & drawing 300B high voltage  circuit with delay on function.
Main power switch setup in 300B case.
High voltage will be remote turn-on and through Jump wire supply to 300B case.


Design & drawing 300b signal amplifier & 300B bias circuit.
Calculate 6C45pi & 300B plate voltage.


Prepare all components  & 300B tubs.


Do placement & hand drill hole for Mount 5U4G & delay on Relay.
High voltage & chock transformer will mount on this box too and  separate circuit with 300B case.


Do placement & hand drill hole for mount 6C45Pi & 300B platform.
6C45Pi & 300B  high voltage & bias circuit will fix in the case.



Mount 6C45Pi & 300B platform structure picture.

Toy3 D/A couple capacitor of Balance output estimate -2 more cap. & different value

D/A couple  capacitor of Balance output estimate -2 more cap. & different value


Unknown PP couple capacitor.
Audio shallow, Sounds too rough.


Bennic PP couple capacitor.
Sounds not rich.


Old CDET 2.2uf/200v  PP couple capacitor
Clear body line sound cool & thin.
.

New CDET 5uF/100V PP couple capacitor.
Clear body line sound better than before.


ROE 10uf/68V pole couple capacitor
Clear body line sound got a little lite mean sound density not enough.



ERO 4.7uf/100V PP couple capacitor
More sound detail ,sound density enough but Low frequency responce not good feel empty.


ERO 6.8uf/100V PP couple capacitor
More sound detail ,sound density enough Low frequency responce  feel better now.


ERO 10uf/250vV PP couple capacitor.
Better response ,sound field of the deep carved ,Low freq. got vigorous tone.
All benchmark base on WM8741+PWM Filter OP AD827AQ+ Differential combiner OP AD797AN.
Sonic Frontiers Corp. have a research paper mention one type D/A usage same value 10uf cap. is better too .
For your reference.