4P1L

4P1L Triode

SPICE model for the 4P1L can be found here

4P1L Pentode Vg2=150V

SPICE model for the 4P1L in pentode mode can be found here4P1L pentode Vg2=100V

8 Replies to “4P1L”

  1. Pentode curves! Good job Ale, thanks. Do you have any info about G2 current value?
    Just finished pentode spice model, but Ig2 looks like too large.

      1. Ofcourse. This is a LT spice model.
        KG2 (Inverse Ig2 sensitivity) is a sizable. But who knows, perhaps it is good.

        .SUBCKT 4P1L 1 4 2 3 ; Ug2=150V; (E74GD – 6.1.13.)
        + PARAMS: MU= 9.2 EX= 1.362 KG1= 1468 KP=510 KG2=4200
        + KVB= 48.8 VCT= 0.00 RGI=220
        + CCG=9P CPG1=0.1P CCP=9.5P
        RE1 7 0 1G
        RE2 8 3 1G
        E1 7 0 VALUE= ; E1 BREAKS UP LONG EQUATION FOR G1.
        +{V(4,3)/KP*LOG(1+EXP((1/MU+V(2,3)/V(4,3))*KP))}
        G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1*ATAN(V(1,3)/KVB)}
        G2 8 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG2*(2.5708-ATAN(V(1,3)/KVB))}
        E2 8 4 VALUE={0}
        RCP 1 3 1G ; FOR CONVERGENCE
        C1 2 3 {CCG} ; CATHODE-GRID 1
        C2 1 2 {CPG1} ; GRID 1-PLATE
        C3 1 3 {CCP} ; CATHODE-PLATE
        R1 2 5 {RGI} ; FOR GRID CURRENT
        D3 5 3 DX ; FOR GRID CURRENT
        .MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
        .ENDS

        1. Thanks,
          Just tried my version of it, see the post I created on 4P1L pentode spice model. Can you try the model?
          cheers
          ale

          1. Yes Ale, I can when involved your values ​​in my model.
            Beautiful !!!
            Im big fan of pentode mode drivers for output triodes. I have C3g ->300B and
            C3m ->6C33C.

            Just tried the first attempt to simulate 4p1L->300B with 5K OPT primary.
            Very encouraging !

            Vin=2Vrms, Pout=8,7Wrms, THD=1,8% (k2=-18dB, k3=-17dB, k4=-53%, k5=-59dB, k7=-70dB).

            4P1L op. point:
            240V/90V/-4,2V, Ia=15mA, Ig2=5,5mA.
            Low current CCS`ed shunt fed series mosfet to regulate Ug2.
            RC filter on cathode,
            Ra=6K8

            Rajko

          2. Great, please test it and let me know.
            4P1L likes currents above 20mA. What is the distortion of the driver?
            I’m sure I did my tests in the wrong bias point
            The mu follower gyrator is better as a load for a driver, I wouldn’t use an CCS..
            ale

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