Amazing natural sound.
Not as much bass loss as expected compared to the Altec octal output transformer referred to on a previous post.
Mid and highs sounded more natural than the Altec. Further tests needed.
Signal Path:
Grampian 25-50 Ω ribbon mic - Pleiades input transformer (2.5mH:2.5H) on Magnetec 073 - coupling capacitor - grid of EF183 triode connected - Pleiades output transformer (16H:140mH) on Magnetec 070 - Realistic Disco Mixer mic in - Sennheiser HD580
A few MΩ connected from Anode to control grid to free electrons.
Total power supply a 6V lead acid battery.
Cathode is underheated by a series 11Ω resistor to reduce cathode temperature and the practically infinite number of electrons near the grid.
Anode current was approximately 70 micro amperes.
The setup needs to go from breadboard to hard wired stage as at such low level signals and sensitivity the gentlest touch of a wire can sound dramatically loud and may change the quiescent anode current.
Not as much bass loss as expected compared to the Altec octal output transformer referred to on a previous post.
Mid and highs sounded more natural than the Altec. Further tests needed.
Signal Path:
Grampian 25-50 Ω ribbon mic - Pleiades input transformer (2.5mH:2.5H) on Magnetec 073 - coupling capacitor - grid of EF183 triode connected - Pleiades output transformer (16H:140mH) on Magnetec 070 - Realistic Disco Mixer mic in - Sennheiser HD580
A few MΩ connected from Anode to control grid to free electrons.
Total power supply a 6V lead acid battery.
Cathode is underheated by a series 11Ω resistor to reduce cathode temperature and the practically infinite number of electrons near the grid.
Anode current was approximately 70 micro amperes.
The setup needs to go from breadboard to hard wired stage as at such low level signals and sensitivity the gentlest touch of a wire can sound dramatically loud and may change the quiescent anode current.
No comments:
Post a Comment