Electronics workbench alternative for tube sumulation

Discussion in 'General Electronics Chat' started by music_man, Dec 21, 2010.

  1. music_man

    Thread Starter New Member

    Jun 23, 2010
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    Hello group, I have been out of electronics for several years. I've had a demo cd of electronics workbench a few times over the years. I really like the drag and drop approach. It just seems like a pretty nice flow. I have used programs where I have had to put in a bunch of device perameters in and I don't really like that kind of program, the simpler to kick out a circuit the better. Anyway the price of electronic workbench is just to much for me. I see there are some spice programs out there and used one about 15 years ago in college. But it was no where near as simple to set up as electronics workbench.

    I am wanting to set up some tube circuits, el34, el84, 6l6, 12ax7 type stuff. Anyway if anyone knows of a circuit design program that may suit my needs please let me know.

    Thank you very much
     
  2. music_man

    Thread Starter New Member

    Jun 23, 2010
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    Hello again, I was browsing around the web and saw a program called super spice http://www.anasoft.co.uk/ I downloaded it... I see it has some tube models in it, a big plus for me. Does anyone here use this program, how does it differ from a modern day spice program. One reason I liked electronics workbench was I just grab the modeled dvm or o-scope and measured. This spice don't seem that user friendly but cost factors, I may have to do something like this?
    thanks again for any input
     
  3. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Electronics Workbench is now National Instruments Multisim Ver 11

    A student/limited version is available for download.
     
  4. music_man

    Thread Starter New Member

    Jun 23, 2010
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    Thanks for your feedback thatoneguy, I was on there site quite a while looking at the student version today. I couldn't find a place where they listed what parts come with the student/limited version. I really am looking for something with tubes. That would be perfect if it did offer tubes in the parts bin, I thought since it was stripped down, it probably didn't. I don't need anything to big, not trying to design a rocket ship or anything. Just some tube amp ideas.
     
  5. music_man

    Thread Starter New Member

    Jun 23, 2010
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    I also downloaded a program called LTspice IV yesterday. It appears pretty popular. I found some files, so I thougth at various sites and they had some tube circuits but I have not been able to get them to open so far. I have had a computer since 1990 and I feel my kids know more about them than I do.. But I shall march on, as always thanks for any constructive input you can provide
     
  6. music_man

    Thread Starter New Member

    Jun 23, 2010
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    Does anyone know what I am doing wrong? I go to this site called duncanamps and I try to download what I believe to be a circuit called spice 34f. I try to save, the files name after I click save is dmtriodes.inc I tell it to save in an educational folder in LTspice, where it seems like all the example circuits are stored? Whenever I do, it appears to reinstall LTspice instead of saving the file inside. This program may be just what I am looking for, I wish it had the fancy interface of multisim, but it may be perfect if I can get it figured out. Thanks for your patience and any help you can provide. Signed severely confused.
     
  7. music_man

    Thread Starter New Member

    Jun 23, 2010
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    So I got the file to open up, unfortunately I don't know what it is and how to apply it. I am sure the file is usefull if I knew what the hey it was. Instead of if it being some sort of an amp it is some sort of a text file.

    Here is a sample:

    **********************************************************************
    * GENERIC: 6BM8 / ECL82
    * MODEL: NH6BM8
    * NOTES: No grid model
    **********************************************************************
    .SUBCKT NH6BM8 A G K
    * ANODE MODEL
    BLIM LI 0 V=(URAMP(V(A)-V(K))^ 1.5 )* 10
    BGG GG 0 V=V(G)-V(K)--0.5
    BRP1 RP1 0 V=URAMP(-V(GG)* 0.030667 )
    BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)
    BRPF RP 0 V=(1-V(RP2)^ 5 )+URAMP(V(GG))* 0.587
    BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.035 )))
    BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 50 )
    BEP EP 0 V=(V(EM)^ 1.5 )*V(RP)* 0.00000256
    BEL1 EL1 0 V=URAMP(V(EP))
    BEL EL 0 V=V(EL1)-URAMP(V(EL1)-V(LI))
    BLD LD 0 V=URAMP(V(EP)-V(LI))
    BAK A K I=V(EL)
    * GRID MODEL
    BGF GF 0 V=(URAMP(V(G)-V(K)- 0 )^1.5)* 0
    BG G K I=V(GF)+V(LD)
    * CAPS
    CAK A K 0.000000000004
    CGK G K 0.0000000000027
    CGA G A 0.000000000004
    .ENDS
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Have you joined the Yahoo! LTSpice Users' Group?
    Link: http://tech.groups.yahoo.com/group/LTspice/

    You'll need to establish a free Yahoo! account, and then request to join the group.

    There are LOTS of Spice models available.

    Once you're a member of the group, there are some tube models that Charles Rydel uploaded available at this link:
    http://tech.groups.yahoo.com/group/...age number/msg 3896 4209/ DC Operating Point/

    I'm doing a bit of fiddling with the standard triode.asy, tetrode.asy and pentode.asy symbols to see if I can get them to work. For some reason, Charles only gave the pentodes in the Rydel library Anode, G1, G2 and Cathode, no G3 :confused: So for the meantime until that can be figured out, just go with the triodes and tetrodes.
     
  9. music_man

    Thread Starter New Member

    Jun 23, 2010
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    Thank you SgtWookie, I will go to where you directed. Thank you for the links. And if you are/were a military member, thank you for your service. I am just wanting a few circuits to knock around on. Instead of going to my shop an blowing things up in person :D.
     
  10. marshallf3

    Well-Known Member

    Jul 26, 2010
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    The third grid in a pentode is usually irrevolent, it's often connected to ground just to keep electrons bouncing back from the plate.
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    Yeah, I know - However, it also serves to make the tube/valve a lot more linear.

    That's why they made pentodes to begin

    Why didnt they leave connections for the pentodes?

    You tell me.
     
  12. SgtWookie

    Expert

    Jul 17, 2007
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    OK, making just a bit of progress.

    See the attached simulation of a 12AX7 triode, made from an extraction from Charles Rydel's library and a mod of the furnished LTSpice triode.asy symbol file.

    I separated Charles' library into three different libraries for triodes, tetrodes and pentodes, and added the names of those libraries to r_triode.asy, r_tetrode.asy, and r_pentode.asy.

    There are no provisions to add new devices to the LTSpice menu bar. However, if you have a number of subcircuits in a .lib or .sub file, you can fill out one existing model in the SpiceModel field of the .asy file, and then you can use the scroll window for the SpiceModel to select other defined subcircuits in the library.

    In the attached simulation, I right-clicked on the instance of the tube to pop up the Component Attribute Editor dialog, shown on the right. Then I double-clicked on the right side of the "SpiceModel" field, and the down arrow is displayed - clicking on that down arrow brings up a scrollable list of all models in the .lib file.

    Note that you have to double-click on the blank box to the right of the field to "X" it so that the name of the model will be displayed on the schematic. For some odd reason, you can't select it to be shown by default - I haven't figured that part out yet; maybe someone else knows how to do it.

    [eta]
    Rydel_triodes.zip is attached; it contains three files:
    Rydel_triodes.lib - belongs in Program Files\LTC\SwitcherCad\lib\sub
    R_triode.asy - belongs in belongs in Program Files\LTC\SwitcherCad\lib\sym\misc
    Triode test.asc - belongs in Program Files\LTC\SwitcherCad
    Once you've put the Rydel_triodes.lib and R_triode.asy where they belong, close LTSpice if it's running, and try loading/running the Triode test file. Experiment with selecting different tubes from the list.
     
    Last edited: Dec 24, 2010
  13. SgtWookie

    Expert

    Jul 17, 2007
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    OK, now for the tetrodes - same routine as last time.

    Note that you MUST select a valid tube from the SpiceModel list before you'll get anything resembling a valid simulation run.

    The test simulations were extremely basic and non-scientific; I didn't even bother looking in my RCA tube manual to see what ranges of voltages or biasing I should use with the tubes I selected. Your mileage may vary; caveat emptor.
     
  14. marshallf3

    Well-Known Member

    Jul 26, 2010
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    A lot of the tubes already had the pentode's third grid internally connected directly to the cathode.

    Care to try for a pentagrid converter? Probably couldn't find those tubes anymore anyway and they're really of little use in what anyone might be designing nowadays. I think most people are just trying to make simple preamps for which you've kindly put in the most popular, a 12AX7 which is similar to an AT7 or AU7. I think the only other model one might want would be for the good old 6L6GT or a 7591.
     
  15. SgtWookie

    Expert

    Jul 17, 2007
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    Hmm. I suppose I could whip up a special symbol for the Rydel pentodes; just copy the existing pentode and show the 3rd connected to the cathode...

    6L6WGTR is in with the triodes, 6L6WGT is in with tetrodes. Will those work for ya? :)

    [eta]
    Rats - the tetrode and pentode models don't seem to be working correctly in LTSpice. Didn't notice that before.
     
    Last edited: Dec 25, 2010
  16. bertus

    Administrator

    Apr 5, 2008
    15,638
    2,343
    Hello,

    I do not have any spice models, but here is a page with a lot of tube datasheets:
    http://www.nj7p.org/

    I hope you can use the data to create some spice models.

    Bertus
     
  17. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
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    The nice thing is that those power amp tubes are fairly forgiving and there are 1,000s of circuits already out there that can be copied from. For absolutely no reason whatsoever I'm going to build a pair of mono tube audio amps some day, possibly even using radio transmitter output tubes but it would be more just for the looks. Luckily power transformers are still easy enough to come by but matching output transformers becomes a problem unless you stick to 4 6L6 or 7591 tubes.

    As to power transformers it's a wonder what you can do with the industrial ones designed to bring 480V down to 120V if you hook one up in reverse, picked up a couple of new ones off eBay for a song a few years ago, both rated for 1KW each thus they'd just be idling running 100W amps which is about the limit of 4 common output tubes. It has been done with RF transmitting tubes but the output transformers and associated driving circuitry for common triodes or tetrodes gets a bit more complex if you want a good frequency response and low distortion. A few of my JBL tower speakers will easily handle 400W RMS but I'd probably end up building speakers myself as well.

    Just another project I really have no need for but might be fun in my older years.
     
  18. music_man

    Thread Starter New Member

    Jun 23, 2010
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    0
    Hello again group, I hope everyone had a Merry Christmas, this is really a nice forum. I think I am almost ready to pull the trigger on the multisim student edition. It is cheap and simple, sort of like me:) I don't believe it has tube models, but I think there is a way to add them? At least I am hoping. I really like the drag and drop interface of multisim and the meters seem like they are what you would encounter in real life. I just watched a few video's on youtube. I hope I can make some simple tube circuits. I think it is limited to 50 components on the student version. I wish I had a lot of money. I have followed electronics workbench for many years and all I could ever afford is the free demo. Anyway thank you all very much for your comments and I wish all you a Happy New Year.
     
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