{"id":1419,"date":"2013-04-01T17:42:46","date_gmt":"2013-04-01T16:42:46","guid":{"rendered":"http:\/\/www.bartola.co.uk\/valves\/?p=1419"},"modified":"2013-04-01T17:42:46","modified_gmt":"2013-04-01T16:42:46","slug":"4p1l-triode-spice-model","status":"publish","type":"post","link":"https:\/\/www.bartola.co.uk\/valves\/2013\/04\/01\/4p1l-triode-spice-model\/","title":{"rendered":"4P1L triode SPICE model"},"content":{"rendered":"

After playing for some time with Dmitry’s great DHT composite triode models, I looked at refining the model by matching my own set of curves of the 4P1L in triode-mode. Here is my take on it:<\/p>\n

\"4P1L<\/a>And here is the SPICE model:<\/p>\n

*** 4P1L TRIODE ******************************************\r\n* Created on 04\/01\/2013 10:53 using paint_kit.jar\r\n* www.bartola.co.uk\/valves \/ valves@bartola.co.uk\r\n* Created by Ale Moglia from curve tracer\r\n* Curves image file: 4P1L Triode.jpg\r\n* Data source link: www.bartola.co.uk\/valves\r\n*----------------------------------------------------------------------------------\r\n.SUBCKT TRIODE_4P1L 1 2 3 4; Plate Grid K1 K2\r\n+ PARAMS: CCG=3P CGP=4P CCP=2P\r\n+ MU=8.16 KG1=1702 KP=124\r\n+ KVB=533 VCT=0 EX=1.59 RGI=2000\r\n* Vp_MAX=500 Ip_MAX=0.08\r\n* Vg_step=5 Vg_start=5 Vg_count=11\r\n* END PARAMS -----------------------------------------------------------------------\r\n* cathode resistor is (2.1V\/650ma) = 3.23 ohm, the pins K1 and K2 are 0.807 ohms from the ends of it\r\nRFIL_LEFT 3 31 0.807\r\nRFIL_RIGHT 4 41 0.807\r\nRFIL_MIDDLE 31 41 1.615\r\nE11 32 0 VALUE={V(1,31)\/KP*LOG(1+EXP(KP*(1\/MU+V(2,31)\/SQRT(KVB+V(1,31)*V(1,31)))))}\r\nE12 42 0 VALUE={V(1,41)\/KP*LOG(1+EXP(KP*(1\/MU+V(2,41)\/SQRT(KVB+V(1,41)*V(1,41)))))}\r\nRE11 32 0 1G\r\nRE12 42 0 1G\r\nG11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))\/(2*KG1)}\r\nG12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))\/(2*KG1)}\r\nRCP1 1 3 1G\r\nRCP2 1 4 1G\r\nC1 2 3 {CCG} ; CATHODE-GRID\r\nC2 2 1 {CGP} ; GRID=PLATE\r\nC3 1 3 {CCP} ; CATHODE-PLATE\r\nD3 5 3 DX ; FOR GRID CURRENT\r\nD4 6 4 DX ; FOR GRID CURRENT\r\nRG1 2 5 {RGI} ; FOR GRID CURRENT\r\nRG2 2 6 {RGI} ; FOR GRID CURRENT\r\n.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)\r\n.ENDS\r\n*$<\/pre>\n
Note that the above triode is with paralleled filaments so it’s running at 2.1V and 650mA. Also this model use the 4-element DHT symbol in SPICE.<\/p>\n
Looking at Dmitry’s parameters on his model:<\/p>\n
*-------------------------------------------------------------------------------\r\n* TRIODE_4P1L_COMPOSITE_5: Russian pentode 4P1L in triode mode.\r\n* Five-element Composite model.\r\n* Created on Wed Mar 16 22:56:00 PST 2005 using tube.model.finder.PaintKIT\r\n* tube data: http:\/\/www.klausmobile.narod.ru\/testerfiles\/4p1l.htm\r\n* http:\/\/www.klausmobile.narod.ru\/testerfiles\/4p1l_vah_10.gif\r\n*-------------------------------------------------------------------------------\r\n.SUBCKT TRIODE_4P1L_COMPOSITE_5 1 2 3 4 ; P G K1 K2\r\nXDHT 1 2 3 4 DHT_COMPOSITE_5\r\n+ PARAMS: CCG=3P CGP=4P CCP=2P RGI=2000 RFILQ=1\r\n+ MU=9.88 EX=1.4 KG1=914 KP=101 KVB=168.5 VCT=0.003 ; Vp_MAX=175.0 Ip_MAX=0.04 Vg_step=2.0\r\n.ENDS\r\n*$<\/pre>\n
We can see that there is a difference in KP which makes both model to perform different from a linearity point of view. Highly linear triodes have KP above 100. Here are some examples:<\/p>\n
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