Digital rig pros and cons
Four weeks ago I put my tube amps and my pedal boards into storage and replaced them with a modeling floor processor and a compact PA system. This odd and somewhat sudden shift came on the heels of two months of trying to find a good way to lighten my rig's carry weight. My search initially concentrated on lightweight tube amps, none of which were entirely satisfactory in terms of performance or weight. Despite earlier admonitions to myself to avoid digital gear, I ended up buying an "all-digital" (including the power amp in the portable PA) rig. This article is an attempt to explore the pros and cons of my decision.
The most obvious assets of a digital rig are its reduced size and weight compared to a tube rig. My digital floor unit weighs a bit over ten pounds and can be carried in a bag slung over my shoulder. If I play in a venue which provides a PA I only have to bring my guitar and the bag holding the floor unit and cables. For a smaller venue without a PA, I can carry my portable PA (stereo, no less) in my free hand. This is a huge win over lugging my tube-based rig, which is over seventy pounds for the amp, another ten pounds or so for a very small pedal board, plus a gig bag with tuner, cables and spare tubes.
Obviously this depends upon the size of your digital rig. If you want to go overboard, you can. I once played with a guy whose digital rig comprised about half of the band's gear. If you can get by with a floorboard processor, though, you're pretty much home free.
A digital rig takes up less space than a comparable tube rig and (assuming an all-in-one construction) can be set up more quickly. Connect power, a DI and a guitar cord and you're done. You don't have to worry about mic placement either, like you would with a tube rig.
Another plus for the digital rig is that the sound is consistent. Not only do you not have to worry about mic placement, but concerns about whether you'll be able to run your amp in its "sweet spot" are a thing of the past. If you set up your modeler "at volume" then your settings are "portable" over a fairly wide range of performance volumes.
Finally, you can get many more variations in your sound without buying any more gear! I know that might not be a plus for some folks, but if you ever got a chance to look at my list of gear that I've once owned and sold (no I will not share that list, it's too embarrassing) you'll see why I might consider that to be a benefit.
If my digital rig goes down, I'm screwed. There are no user-serviceable parts. The beauty of a tube amp is that most failures are tube failures. Tubes are "field replaceable units". As long as you carry a few spare tubes and fuses you can fix 99% of the problems you're likely to encounter with a tube amp. That's the good news for tube amps. The bad news is that tube amps fail way more often than well-constructed solid-state or digital gear. Still, the digital rig tends to require somewhat better care than a tube amp which can typically take tons of neglect and abuse before failing. A digital rig tends to have somewhat more dainty controls and construction than a tube rig, so you'd better be prepared to treat it with respect or carry a spare.
You have to invest time in learning to program a digital modeler, then more time doing the programming to meet you needs. This shouldn't be a surprise: the modeler is a lot more complex (functionally, at least) than your typical tube rig. There's a lot more to learn about, too. Analog circuitry overloads gracefully, even musically; digital processors do not. One of the first things you'll need to learn about is how to keep your modeler out of digital clipping. That's the bad news. The good news is that the modeler can (if you need it to) cover a lot more sonic territory than your tube rig.
One of the reasons that I've avoided modelers for so long is that I really don't want to spend my time programming. But as I've gotten into this, I realize that I did spend a lot of time tweaking my tube rig for way less of a payoff than I get from tweaking a modeler.