Frequency Sweep Graph - How?

[artofharmony]

I see graphs all the time of people showing the EQ curve of pedals, tone stacks, certain sections of pedals, etc. For instance, Electrosmash has graphs like this one: https://electrosmash.com/images/tech/ds1/boss-ds1-op-amp-stage-freq-response.png

Does anyone know a good way to create those graphs from a schematic? If I have to learn Spice, I will lol

[FiveseveN]

Yes, you have to learn SPICE
That's to satisfy the from a schematic requirement. If you have a physical incarnation you can just measure it.

[GGBB]

Yes, you have to learn SPICE
That's to satisfy the from a schematic requirement. If you have a physical incarnation you can just measure it.

There's at least one other option (that I know of) - TINA-TI. It's actually SPICE-based but IME the interface is simpler and easier to use than for example LTspice (it's been years since I've used that though - maybe it's improved).

[FiveseveN]

That's why I said SPICE in general and not a particular implementation. I've been using Micro-Cap 12 myself after many years of wrestling with LTspice.

[ElectricDruid]

Yes, you have to learn SPICE
That's to satisfy the from a schematic requirement. If you have a physical incarnation you can just measure it.

Actually, even if I have the actual circuit, I'd *still* use LTSpice to generate the graphs because it's simply easier than doing measurements and plotting a graph. I *could* do an FFT on the o'scope, but it's not half so detailed or easy to read, and I'd have to save it to a USB stick and then transfer that to the computer etc etc. I *could* take a ton of readings at specific frequencies and then get excel or something to provide me with a graph, but life's too short. LTSpice is pre-DOS-era software dragged kicking and screaming into the 21st century, but it does work very well, and it *is* free, and I can put a schematic into and get a result out in not *too* long these days, having got familiar with its delightfully "quirky" interface...

[PRR]

You can analyze a schematic and derive the frequency response in as much detail as you like. In most audio it is fairly simple. I derived the Fender Twin on paper before "modern" methods.

Measuring response used to be simple. I have measured and plotted a few dozen points and plotted them on graph paper. (Audiologists still did that a decade ago, as seen in Dad.)


For mass measurements: Variable frequency audio oscillator (usually a BFO). Pen recorder (you know it as the magic part of a Lie Detector). Chain to keep the two machines in sync. That used to be a big part of GR and B&O. A late self-plotter:

[GibsonGM]

LT Spice.   "STEP PARAM"     Once you get LT running, you'll find help in the Simulation sub-forum here, and online. 

[artofharmony]

Thanks for all the info, y'all! I've got a lot of options to try.