I tought it could be an interesting exercise to compare a Digitech GSP1101 amp simulation with the corresponding real amplifier. So I had a go, testing a real Marshall JCM 900 Head (the amp I own) and its simulation. Obviously this kind of comparison it's bound to be quite subjective, however its results were for me rather unexpected. During the test, what I felt "under my fingers" was more or less the same, both with the amp and its emulation. Even from a "tone" point of view, the final results were very similar.

Some necessary explanation

GSP1101 is plugged between the amp's send/return. GSP1101 presets allow you to choose between the real valve preamp section (the JCM 900 Marhall's one, in this case) and a pre-amp simulated by Digitech.

The simulated pre could be one of the many simulations avaible in this multieffect (e.g.: Fender Bassman or Twin Reverb, or a Triple Rectifier, etc.), As you may expect, in order to get a fair comparison I chose the JCM 900 simulation. A cool feature on the GSP is the rotating main knob, which let me dial the 'real' tube tone or the simulated one just flicking it back and forth.

Of course, when the GSP1101 pre simulation is selected, the Marshall real tube preamp is completely bypassed thus excluding the amp's gain and tone controls, leaving the master volume the only working dial (which belongs to the amp's power section anyway).

To get a fair idea of the differences between the tones, I chose not to add any other on-board effect, using just a dry preamp simulation. All equalization parameters were flat. The cabinet I used was a Marshall 1922.

 Final considerations

It is not my goal to change people's mind in considering one system better than the other. Personnally, I have an "analog mind". However I'm glad to judge without any preconception typical of this kind of discussions (the eternal struggle between digital and analogic...).

In fact on stage I'll keep using my analogic preamp tones, but I have to say that messing with the different combinations of this digital unit (preamps, effects and cabinets' simulations) is priceless.

Strat 1