music, guitars & other obsessions


Yet Another Simulator – Micro-Cap

Harmonic Content

While searching for other ways to generate THD/IMD vs output power plots, I came across some application notes from Spectrum Software, the maker of Micro-Cap, an expensive simulation package used by the pros. Luckily there is a student/trial version available for download so I can test its features.

With the program, it is very easy to generate the distortion vs output plots, which makes me wonder why the other programs do not offer the same… All Micro-Cap does AFAIK, is to store the various results of the distortion data in memory then plot them out afterwards – so the user is relieved from the hassle of exporting the data to another program like Excel to plot the curves.

Of course, the program has many more features besides THD/IMD, according to the company, components can be optimized to minimize the distortion, as well as many other parameters. The optimizer can also be used to build custom SPICE models based on the manufacturers’ datasheets, unfortunately, this feature is not enabled in the trial version of the program, so I can not test it out. But I can see how it could come in handy to do curve fitting and generate the tube models.

The full program is very expensive, with retail price around $5,000! Really?! For a souped-up version of Berkeley SPICE?! Come on! In any case, with some well thought-out coding, I think the distortion plots could be done just as easily with SpiceOpus or any other free or low cost SPICE programs. It comes down to how much time I want to spend on programming instead of actually using the simulator 😉 Oh well, there is no such thing as a free lunch, is there?!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s