For some reason I have taken a desire to build a 300B PP amp that is driven balanced. In doing alot of reading and research, I thought it would be interesting to model the plate voltage / current characteristics of the 300B to help decide on the driver stage tubes. I wanted to take this a step further and allow the max power and load to be plotted based on load impedance.
I think that this idea may be too aggressive given the capacity of MS excel, MY IQ, or the fact that I must take into consideration other variables not presented in the data sheets.
I have digitized a 300B plot and have found the bias curves fit a polynomial function. What I found interesting, and ultimatley the demise of this idea so far, is that the constants for the polynomial function don't follow any continuous specific function vs. bias voltage.
They do exhibit a piecewise function that tends to peak at the nominal operating point of the tube as described in the data sheet.
What am I seeing here and what is the significance of it? Is there a better way to model a tube without spice?
Thanks
Scott
I think that this idea may be too aggressive given the capacity of MS excel, MY IQ, or the fact that I must take into consideration other variables not presented in the data sheets.
I have digitized a 300B plot and have found the bias curves fit a polynomial function. What I found interesting, and ultimatley the demise of this idea so far, is that the constants for the polynomial function don't follow any continuous specific function vs. bias voltage.
They do exhibit a piecewise function that tends to peak at the nominal operating point of the tube as described in the data sheet.
What am I seeing here and what is the significance of it? Is there a better way to model a tube without spice?
Thanks
Scott
Hi Scott
Spice is one thing, models are another thing.
Yuo can model a triode byusing polynomials,
or you can profitably use a specific model like the one
from koren.
Then you can put the model in spice format
or in Excel format or in BASIC language
but this is another thing.
I advice you to download some user frendly ECAD
software like Micro-Cap.
bye Federico
Spice is one thing, models are another thing.
Yuo can model a triode byusing polynomials,
or you can profitably use a specific model like the one
from koren.
Then you can put the model in spice format
or in Excel format or in BASIC language
but this is another thing.
I advice you to download some user frendly ECAD
software like Micro-Cap.
bye Federico
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