Hi *, A while back we had a thread going (that I started) about the differences between the terms "solid state", "analog", "emulator", "modeler", "profiler" etc. There was also a followup round. My intent was to have this be some sort of recurring post for newer people to the group, as these discussions keep coming back to life. I may have started the discussion, but the post below is the summary of discussions involving a number of TDPRI people, please refer to the original threads to see the cast of characters contributing: http://www.tdpri.com/forum/modeling...1482-modeling-analog-digital-solid-state.html and http://www.tdpri.com/forum/modeling...-emulating-digital-solid-state-draft-2-a.html If you have a strong disagreement with the post, might be good to browse through those original discussions as a lot of the disagreements boil down to differing points of view on ill-defined terms like "modelling". Here goes, hope this is helpful especially to newcomers! ------------------------------------------------------------- There's a lot of confusion surrounding the terms listed in the subject. For example we see posts confusing "solid state" with "digital" and "emulation" with "modeling". This post tries to clarify that confusion for the benefit of anyone reading. First let's talk about the terms that are well defined. 1) solid state: this is a pretty old fashioned term actually, all it means for the purposes of amplifier discussions is : no tubes. Technically it means that all the electronic components are constructed out of solid materials. Vacuum tubes are of course not solid -- that's the distinction. Solid state doesn't mean anything else except "no tubes". "Transistor" amps are solid state amps (as long as they don't contain some tubes too, in which case they are called "hybrids"). 2) analog/analogue and digital : analog circuits work on an incoming signal as a continuous value, and the various pieces of the circuit work in the same way. Digital circuits work basically on numbers, doing operations on those numbers. For a guitar amplifier, the input signal is converted to a sequence of numbers, then inside the amp calculations are performed on those numbers resulting in an output signal. Think of analog like a measuring cup: you pour water into it, however much or little you like; depending on how much you pour in, the water level in the cup rises or falls. Digital is like your bank balance : you can only put money in in units of cents. So your bank balance is always a whole number of cents. Usually when people speak of digital electronics, they mean something that works as a computer, because modern computers also work with digital, discrete values ... data are stored in memory locations that can hold whole numbers of various sizes, just like the cents in your bank balance. Analog vs digital is not strictly related to solid-state/transistor/tube. One relation which (as far as we know always holds is tube amps are always analog. But not the other way around ... analog amps are sometimes tube, sometimes solid state. In theory you could build a digital tube amp, but we don't know of any ... so another relation is digital always means solid state. Again, not the other way around: solid-state (transistor) amps are sometimes digital (like a Peavey Vypyr) and sometimes analog (like my old Randall Commander II). There are also some hybrids, like the Vox Valvetronix that has a tube (analog) preamp section and a solid-state (digital) modeling and section. Now there are some terms commonly used (say "marketing hype three times real fast") which are not so well defined. This is what a bunch of us on this forum came up with for definitions to assist us in our discussions, and people new to modeling amps to help understand some of the terms being thrown around. Here are some common terms: a clone or copy is an amp that tries to copy another amp, and that's about it. think of all the '57 deluxe clones out there. an emulator is an amp that (analog or digital, usually digital) tries to recreate sounds by making a "virtual circuit" that is identical to some other amp's circuits. Examples are the Blackstar ID (which emulates different power tubes as well as how a tube would interact with the speaker) and the Fender Cyber Twin. a profiler is an amp that can capture the sounds made by another amp and reproduce them Finally we call a modeler any amp that can be configured to "sound like" other amps, or that allows you to construct a very wide range of specific tones, by choosing different combinations of settings. Given this definition of modeling, it could be achieved using many different techniques, for example: using an emulator principle to simulate various amps, effects, etc as described above using digital (DSP) techniques to transform an input signal into the same output signal an amp or effect would have produced. Technically speaking, this would be emulating the end-to-end signal transfer function, rather than the electronic circuit itself. using a profiling technique to copy how another amp responds to the guitar having an extremely flexible tone stack, power stage, or switchable internal circuitry that allows a wide range of amp sounds to be created. Note this last point is a ill-defined grey area, as it's not well-defined just how flexible your tone stack needs to be for you to call it "modeler". Two examples are the Tech Trademark series and the Egnater Tweaker. The Tech21 web site refers to the SansAmp (which is at the heart of the Trademark) as "analog amp modeling". The Tweaker is not usually referred to, nor marketed, as a modeling amp. However the switches are named "vintage/modern", "usa/ac/brit", similar to the Trademark's "calif/british/tweed" and "us/uk/flat" and even to the Roland Cube's switch between "Black Panel", "Brit Combo" and "Tweed". The intent in all cases is to recreate, or at closely resemble, sounds specific to other amps. So a modeler could be anything from an extremely flexible analog solid-state amp, or tube amp like the Tweaker, to a DSP-based amp like the Peavey Vypyr or Fender Mustang, to a profiler -- the main point of modeling is not "how you do it" but "what are you trying to do" -- and that is to sound like multiple other amps. Emulator, DSP, very flexible tone stacks, profiling -- this all refers to the "how you do it" part. Hope this post helps further understanding and useful discussion in this forum!