Hello everyone,
I am thinking to start learning DSP from a long time, and the problem with self study, it is quite hard to find good structured resources and then i get lost in combinations of mathematical symbols, e, i, pi, what not.

Given, this community have many experts, can we compile a list of resources for beginners (self study ) or prerequisites (maths concepts atleast the intution ) and then may be scope of work people can get after pursuing DSP. Although i dont know much about this field, but i can help wherever needed to compile, format.

Sorry, if it has been already discussed.

I’m trying to understand what modeling approaches are actually used in commercial guitar amp simulators such as Fractal Audio, Neural DSP, Line 6, Kemper, and similar products.

From the publicly available descriptions, my current understanding is roughly the following.

Fractal Audio describes its amp models as component-level physical models of elements such as the preamp tubes, tone stack, cathode follower, power supply, phase inverter, power amp, and amp-speaker interaction.

Line 6 also describes Helix as using component or small-circuit modeling, with multiple digital stages corresponding to filters, gain stages, tube stages, and tone-stack behavior.

Neural DSP has published research on controllable black-box neural amplifier models. Their approach trains a neural network using input and output audio together with the physical amplifier’s control positions. Neural Capture also appears to be a black-box learned model.

Kemper appears to use a profiling approach rather than reconstructing the original circuit.

What I am unclear about is what “component-level” or “circuit-based” modeling means in an actual real-time commercial implementation.

Are companies such as Fractal solving a reduced system of nonlinear circuit equations in real time, using methods such as nodal analysis, wave digital filters, or state-space models like SPICE?

Or does component modeling usually mean a gray-box structure composed of digital filters, waveshapers, feedback paths, and dynamic nonlinear blocks that are designed from the original schematic?

Would Line 6 and Fractal be considered true white-box circuit models, or are they better described as circuit-informed gray-box models?

I’m also wondering whether most commercial products are hybrids. For example, a circuit-informed or neural model for the amplifier, oversampled waveshaping for some nonlinear stages, and convolution for the speaker cabinet.

Are there any companies that are publicly known to perform genuine real-time circuit simulation rather than using circuit-inspired DSP approximations?

I’m mainly interested in the implementation principles rather than which product sounds best. Papers, patents, technical presentations, or open-source examples would be appreciated.