I think most of the traditional single pedals/stompboxes are solid state but not necessarily digital. There should be stompboxes that uses tubes inside i think.

http://www.freeinfosociety.com/electronics...view.php?id=130




I think only multi-fx pedals (especially the smaller ones) should be digital since it would be impractical to fit so many solid state parts to accomodate tons of settings/patches, that's why they tend to have dedicated DSPs inside (their version of intel cpu) combined with their firmware and adc/dac convertors to do the processing.

Digital is not necessarily bad. Older digital processing pedals sampled the guitar pickup signals at lower rate so when converting modified data back to analog, losses in quality are noticeable.

96khz sampling in some of the new multi-fx units such as zoom g1 captures signal at twice the usual rate that even many PRO gear equipments doesn't.

This ensures that when converting back to analog, the original source of the signal loss isn't noticeable even to most humans.

The only problem lies with the way the sampled data is modified, so that quality is dependent on the chipset's (for example, Zoom's ZFX-3) mathematical functions and algorithm, IE, job of the programmer and also the engineer who designed the CPU. If the programmer/engineer isn't a tone freak or a guitar expert, very hard for him to do a good job. It's rare for you to get an employee who's a code demon and an accomplished guitarist with good gear knowledge so this is why there're not that many good digital multi-fx units out there.

DAC/ADC has gone a long way unlike the old days, it's bound to catch up with analog stuff for quality one day. At least now we don't have to worry about quality losses from digitization (Just up the sampling rate from 48khz to 96khz). Now what's left is just the way the programmers code the emulation/modeling functions to modify the digitally sampled data, and that will affect the type of sound/tone you get.

The digital method is dependent on how many sort of layers of algorithm are performed on the sampled data. For clean sound, make no mistakes. The cleans of the digital are way way too clean and rivals that of any others, if you like it truly clean, because digital processing is very famous for noise reduction and etc in this regard.

For distortion/overdrive, the easy part is replicating the way the solidstate devices work on the data, no problems. It's when other factors that are unpredictable, such as cabinet/speakers and valve tubes (different tubes behave differently) come into action, and also room temperature, size, parts age, wood, how many walls... etc.. all these ultimately affect your sound, and to emulate all these would take quite a ton of processing power and memory, that's why most mfx units and amp modelers would have to cut out some of these parameters from the calculation so you only end up with a tone that is 'clean' in distortion.

If given enough of CPU power, enough of research into physics, maths, algorithms to simulate the conditions that affects electronic circuits, i have no doubt digital technology can reproduce what we want in the real world. Star Trek's holodeck comes to mind.

The king of PC amp modeling would have to be amplitube 2 and guitar rig i think.