Posted by MQracing [ 151.197.124.169 ] on October 06, 2005 at 12:54:50:
In Reply to: and a link posted by PakProtector on October 06, 2005 at 10:53:29:
I remember well working with Voltsec on that paper. Eons ago on another forum at another time... folks were arguing that the L was strictly in parallel with the r sub p of the tube....
they were essentially looking at the small signal model as VS describes it in his paper. But the moreso appropiate model (talking power amps here which is what this paper addresses) for the primary L is that... in a large signal model the primary L is in parallel with the reflected impedance of the output transformers...
I spent much time making these points about the need for L in a large signal model and how to moreso accurately model or describe those interactions and why having a sufficiency of primary inductance was critical... I promise not to ever do those monster threads again...
but... what I would like to point out... is that the guinevere is perhaps more appropiately used in a small scale model... and does NOT employ an output transformer...
from a small signal model (where you are not delivering power) then the plate choke can be modeled as being in parallel with the r sub p of the preamp tube...
If the r sub p of the tube is say 2300 ohms... then a plate choke with about 180 henries will have an AC impedance at twenty hertz of approx ten times the magnitude of the r sub p of the tube... and NOT load the tube in any significant manner.
make a long story shorter... plate chokes have been widely used with success... I won't argue the technicals of this with anyone...
is it worth a try? You bet. Is it simple to try... mechanically yes... expense wise... no. The CCS will be far less expensive to implement than buying a pair of appropiate plate chokes. But plate chokes are an option and perhaps an attractive SONIC option vis-a-vis a CCS load.
cheers,
msl
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