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Old 6th February 2011, 05:02 PM   #991
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Cordell Audio has spice models for a lot of the transistors you would use in audio, which are guaranteed to be very accurate.

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Old 6th February 2011, 05:26 PM   #992
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Turns out the library editing was much easier than I expected. I found a bunch of pspice libraries on the web and just added a huge number of 2SA..2SD devices and most of the TIP devices. There wasn't much in the way of conflicts to deal with. It's all good!

No haven't tried winetricks, but just downloaded it. There's a ton of stuff there. What are the essentials?
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Old 6th February 2011, 05:56 PM   #993
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Linux doesn't have all the required fonts. Windows fonts aren't open-source so WINE can't distribute them. Winetricks will download them from the microsoft site.

Mike has tried to get LTSpice to work on WINE, so installing windows libraries won't necessarily get you anywhere. There may be some peripheral things like fonts that will make it easier. Winetricks can also enable font smoothing like on some versions of windows. Just look through the list, it'll come together.

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Old 6th February 2011, 05:58 PM   #994
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Buckeye, models in general are not very accurate. Some of them are. Vendors churn them out by the thousands, but usually they really aren't representative of the device.

Go to the Cordell Audio website and download the SPICE models. You will thank yourself.

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Old 6th February 2011, 10:11 PM   #995
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Quote:
Originally Posted by keantoken View Post
Buckeye, models in general are not very accurate. Some of them are. Vendors churn them out by the thousands, but usually they really aren't representative of the device.

Go to the Cordell Audio website and download the SPICE models. You will thank yourself.

- keantoken
Hi keantoken,

Thanks for the kind words about the library I put up on my site. I was originally inspired by Andy Connors' work on power transistors, where he looked at just how bad the vendors' models were, and set out to make some better ones. I got involved because I felt I needed better models than vendor models to do semi-decent simulations for my book. Figuring out how to create those needed models actually led to the chapter on how to make models.

I have to say the whole adventure was a humbling experience. After I completed the book, I set out to tweak some of the small-signal transistor models I had been using and was frustrated to learn that they were not that great, either. It was a lot of work to measure and get the models at least close in what seemed to be the more important areas. There were some eye-openers revealed by my measurements of real devices. In many cases I found the manufacturers' number for Early effect, VA, to be way off.

I'll soon be posting an update to the models and adding some. One area where I have been investing effort has been to get RB closer to correct. This is another one where vendor's usually punt. I learned how very difficult it is to infer RB. I originally tried to do it with DC measurements of excess Vbe. That works pretty well with power transistors, but not so well with small-signal transistors. Wrong RB values may give wrong amounts of excess phase in the transistor model and wrong noise simulation measurements. So I have actually been using sensitive noise measurements to better infer RB. So far the results are encouraging.

Cheers,
Bob
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Old 6th February 2011, 10:32 PM   #996
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Hello Bob!

I didn't know there were any models there until recently when a friend pointed them out. I was glad to learn that the idea of DIY models wasn't totally lost.

I often find myself fixing crazy errors in models I use. For example, the KSC1845 model gives an RC of 180R. Because of this, VceSAT was broken and current mirrors wouldn't work. For a newcomer who expects a vendors' own model to be accurate, it is a put-off to 'discover' that the fast, low-noise transistor won't work for their project.

Good luck with the models. It is a service to the DIY community.

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Old 7th February 2011, 03:41 AM   #997
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Quote:
Originally Posted by Buckeye View Post
Thanks for your offer to help. Here is the picture:

Attachment 208419
your problem here seems to be that the base of Q6 should connect to the collector of Q7, not the emitter. (that's the most obvious one, the implementation of the darlingtons is another one)
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Old 7th February 2011, 06:43 AM   #998
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Thanks Jed, Jon got me pointed in the right direction.

I loaded Bob's models and look forward to using them.

Got sidetracked by winetricks. Loaded some wine components and kind of messed up my system. I'm not sure which of the tricks did this, but my LTspice toolbar icons are unreadable because of the colors. I've been trying to figure this out without luck. I have several WINE apps that are doing this now. I think it has to do with the use of transparent color which is rendered as black.

LTspice seems to be the only app I have that uses transparent color in the toolbar so it's the one that's a problem.

I'm guessing this is a transparency rendering issue.

Here's what my LTspice menu looks like in WINE.

ltspice-toolbar.png
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Old 7th February 2011, 12:18 PM   #999
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winetricks trick: load only one download at a time. if a dll or something messes up wine, you know which one did it...

still, having the base of your negative side output effectively tied to the negative rail through a 33 ohm resistor is going to make the sim not work... it should be on the collector of the VAS, which is where the voltage swing is developed
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Old 7th February 2011, 12:39 PM   #1000
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Yes, thank you. JonHarrison pointed out that very same thing. Please don't rub it in...
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