Posted by PakProtector [ 152.163.100.65 ] on December 31, 2005 at 09:00:56:
In Reply to: Re: Small HV caps, and pentodes driving power triodes posted by Damir on December 31, 2005 at 08:49:30:
Hey-Hey!!!,
No plan to use the autoformer/ct choke as a PI. Going to use a diff pair, with a common g2 supply. The g2 would be resistor dropped, and c-bypassed to the common cathode node( riding a MOSFET CCS ). This would be the same sort of thing the cascode achieves by referencing Ec2 to the common cathode as drawn in the Merlin schematics.
The autoformer/ct choke also leaves only 1/4 of the end-to-end inductance, instead of 1/2 the end-to-end inductance one gets when driving it balanced, in pure grid choke form. It's the same effect as a Class A v. Class AB OPTx load.
Interleaving also increases the Cw...and I'd prefer to have that as low as is achievable, given the other design requirements. On the capacitive load, the better sonics of the cascode MOSFET CCS is largely due to reducing the shunt capacitance( IMO ), and reducing the Cw of a choke is going to contribute in the same direction. Capacitive loads sound screwey to me, hence the interest in the Cw measurments of the inductive loads. Which gives me another thing to try when I get those interleaved phase splitter chokes in my hands and on the measurement bench...more later when I have developed the idea a bit further.
cheers,
Douglas
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