Dynaco A431 output stage voltage swing

[stereohifi]

60 watts RMS now, Yeah!

Thanks to all helping , Petertub of mod the 100Kohms resistor for bias did it!
In fact as per tube specs for KT120 i did installed a grid resistor of 47Kohms.
I do have an octet of those for this mk3 Dynaco matched pairs.



I get now 60 v p.p. at onset of clipping. translated to 60 watts rms in 8 ohms.
I did find a bit weird that minus bias volts did limit the swing voltage to drive to output stage.
Because, I have use this bias scheme for modding a self or cathode bias amp to fixed bias that worked fine a Magnum120 of Rogue Audio.
Thanks again and have a nice Easter week-end and stay home safe!!

 

[petertub]

Thanks to all helping , Petertub of mod the 100Kohms resistor for bias did it!
In fact as per tube specs for KT88 and KT120 i did installed a grid resistor of 47Kohms.


I get now 60 v p.p. at onset of clipping. translated to 60 watts rms in 8 ohms.
I did find a bit weird that minus bias volts did limit the swing voltage to drive to output stage.
Because, I have use this bias scheme for modding a self or cathode bias amp to fixed bias that worked fine a Magnum120 of Rogue Audio.
Thanks again and have a nice Easter week-end and stay home safe!!

Glad you made it !


And yes, we will stay at home.