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11th June 2018, 06:15 AM  #1691 
diyAudio Member
Join Date: Apr 2014

Just make your own. Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively You'd be shocked how many canned models are wrong.

11th June 2018, 06:30 AM  #1692  
diyAudio Member
Join Date: Jun 2015
Location: Perth, Western Australia

4D32
Quote:
Google isn't being much help either. I don't have one to put on a curve tracer even if my curve tracers were capable of 1000V and 2.2A. 

11th June 2018, 06:33 AM  #1693 
diyAudio Moderator

Sorry, then you can try playing with the Model Paint Tool as suggested above.

11th June 2018, 06:35 AM  #1694 
diyAudio Member
Join Date: Jun 2015
Location: Perth, Western Australia

I recently found an LTSpice model for superimposing loadlines over standard characteristic curves.
It occurred to me that an LTSpice model that would generate anode characteristic curves from tube models would be very useful for assessing the quality of models. Beyond my LTSpice abilities though. Does anyone have such a model? Thanks! 
11th June 2018, 06:48 AM  #1695 
diyAudio Moderator

They are not really models, just simple schematics. All you need to do in the schematic is to sweep the voltage sources on the plate and the grid for a triode. For the pentode, you add another voltage source for the screen grid, and set the voltage per the datasheets. Before you can do that, make sure you have the correct symbol for the pentode, since many SPICE models online have their pins swapped around.

11th June 2018, 06:56 AM  #1696 
diyAudio Member
Join Date: Jun 2015
Location: Perth, Western Australia

Thanks. I'll give that a try.

17th June 2018, 09:16 PM  #1697 
diyAudio Member
Join Date: Nov 2010
Location: Kansas

6829 SPICE Model
Does anyone have a SPICE model for the 6829? Although I've seen people say that the 12AT7 is about the same as the 6829, a comparison of the two tubes' plate curves doesn't bear this out.
Thanks. 
17th June 2018, 10:19 PM  #1698 
diyAudio Member

6829 = yet another interesting twin triode
https://frank.pocnet.net/sheets/138/6/6829.pdf Definitely not the same as a 12AT7, but awfully close (mu is lower, so rp is lower, gm is about the same).  
17th June 2018, 10:45 PM  #1699  
diyAudio Member
Join Date: Apr 2010

6829_mod.jpg
Quote:
(See attachment.) Code:
.SUBCKT 6829 1 2 3 ; P G C; KOREN MODEL (TRIODE) + PARAMS: MU=55 EX=1.31 KG1=298.75 KP=162 KVB=550 RGI=2000 + CCG=5.0P CGP=3.6P CCP=.57P ; ADD .7PF TO ADJ PINS, .5 TO OTHERS. E1 7 0 VALUE= +{V(1,3)/KP*LOG(1+EXP(KP*(1/MU+V(2,3)/SQRT(KVB+V(1,3)*V(1,3)))))} RE1 7 0 1G G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1} RCP 1 3 1G ; TO AVOID FLOATING NODES IN MUFOLLOWER C1 2 3 {CCG} ; CATHODEGRID C2 2 1 {CGP} ; GRID=PLATE C3 1 3 {CCP} ; CATHODEPLATE D3 5 3 DX ; FOR GRID CURRENT R1 2 5 {RGI} ; FOR GRID CURRENT .MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N) .ENDS Jim 

18th June 2018, 02:14 AM  #1700  
diyAudio Member
Join Date: Jul 2003
Location: Wayne, West Virginia

Quote:
Not to take away from jelanier's post, but here's two models I just made for use in LTspice, one in Curve Captor and one using Ayumi's method... Curve Captor: Code:
* ============================================================== * CK6829 LTSpice model * Modified Koren model (8 parameters): mean fit error 0.186067mA * Traced by Wayne Clay on 06/17/2018 using Engauge Digitizer and * Curve Captor v0.9.1 from Raytheon data sheet * ============================================================== .subckt CK6829 P G K Bp P K I= + (0.02268049449m)*uramp(V(P,K)*ln(1.0+(0.02982574749)+exp((1.560781257)+ + (1.560781257)*((66.6612651)+(1067.129594m)*V(G,K))*V(G,K)/sqrt((40.14838418)**2+ + (V(P,K)(9.147083081))**2)))/(1.560781257))**(1.370120586) Cgp G P 3.1p ; 0.7p added (2.4p) Cgk G K 3.7p ; 0.7p added (3.0p) Cpk P K 0.57p ; 0.2p added (0.37p) Rpk P K 1G d3 G K dx1 .model dx1 d(is=1n rs=2k cjo=1pf N=1.5 tt=1n) .ends CK6829 Code:
* * Generic triode model: CK6829_AN * Copyright 20032008 by Ayumi Nakabayashi, All rights reserved. * Version 3.10, Generated on Sun Jun 17 20:48:19 2018 * Plate *  Grid *   Cathode *    .SUBCKT CK6829_AN A G K BGG GG 0 V=V(G,K)+0.17652075 BM1 M1 0 V=(0.019871805*(URAMP(V(A,K))+1e10))**1.5762085 BM2 M2 0 V=(0.48761325*(URAMP(V(GG)+URAMP(V(A,K))/25.784611)+1e10))**3.0762085 BP P 0 V=0.0047751592*(URAMP(V(GG)+URAMP(V(A,K))/52.879225)+1e10)**1.5 BIK IK 0 V=U(V(GG))*V(P)+(1U(V(GG)))*0.005163113*V(M1)*V(M2) BIG IG 0 V=0.0023875796*URAMP(V(G,K))**1.5*(URAMP(V(G,K))/(URAMP(V(A,K))+URAMP(V(G,K)))*1.2+0.4) BIAK A K I=URAMP(V(IK,IG)URAMP(V(IK,IG)(0.0025236727*URAMP(V(A,K))**1.5)))+1e10*V(A,K) BIGK G K I=V(IG) * CAPS CGA G A 3.1p ; 0.7p added (2.4p) CGK G K 3.7p ; 0.7p added (3.0p) CAK A K 0.57p ; 0.2p added (0.37p) .ENDS
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