Tech Tip:What's the difference between a tube amp and a solid-state amp?

The simple answer is that a tube amp uses one or more vacuum tubes to amplify the signal, while a solid-state amp uses solid-state electronics (diodes, transistors, etc.) to amplify the signal. On paper and in theory these two implementations should yield identical result, but in actuality the difference is usually noticeable.

But the simple answer fails to answer to the complexity of the issue. Many amps are not simply tube or solid-state, but mixes of both kinds, called "hybrids." This usually means that they have a tube preamp stage, employing vacuum tubes in the tone shaping circuitry, but use solid-state circuitry for the power section. The hybrids are closer to full tube amps in response and tonal warmth, but purists will still find a difference between the two. Tube amps are generally more expensive in initial cost and to operate (because you need to replace the tubes occasionally), and solid-state amps are generally less delicate and more reliable. Many players, however, feel that tube amps yield a warmer, more musical tone and better distortion.

Yet another wrinkle is tube emulation circuitry. Many amps and preamps have sophisticated circuits designed to act like tubes, and as in all things, some are better than others. The newest develop in amps are the modeling amps, which not only emulate the tone and response of tubes, but of specific tube amps. These are in general pretty exciting amps, but again, some are better than others at getting specific models, and in maintaining the sounds through a range of volume levels.

Another point to make about tube amps is that bigger is not always better. You get the distinctive tube sound most when the amp is cranked up enough that the tubes are saturated or nearly saturated. For this reason, it is often better to choose a lower wattage amp over a higher wattage amp, depending on how and where you play. By the time you crank up your 60 watt amp enough to saturate the tubes to get just the right level of distortion, you could be blowing your audience out the back door. It might have been better to choose a 20W amp that lets you get your saturated tone without the ear-killing decibels.

Scale Exercises To Improve Your Soloing
In one of the early editions of this column I laid out all seven diatonic scale patterns in the key of C major.  I also explained that you could simply slide those patterns up and down the neck of the guitar to change to different keys (including the minor keys, and yes, I'll get to that long-promised column about relative majors and minors real soon.) Learning these seven diatonic patterns is probably among the most important advances you'll EVER make on the guitar, as they allow you to play all over the guitar neck in an orderly fashion - and they help you to understand so much more about the instrument that I don't even have space to go into it here.
Now I'm going to show you a few different ways to practice those scales, while at the same time turning them into useful riffs you can use as short pieces of a solo. After you work on the following exercises a bit, you'll be able to add these exact scale exercises into solos you're playing in real songs - at your band's rehearsals or shows, or while you jam along with your favorite CD.
For all the following exercises, we'll use the 7th pattern of the C major scale - which we call the "7th" pattern because it is the pattern that starts on the 7th note of the C major scale (C, D, E, F, G, A, B, C). The seventh note of the C major scale is B. This is actually a scale pattern that most guitarists will already be familiar with, though teachers will often skip the first note in the pattern, the B at the 7th fret on the sixth string. The fact that the 7th pattern of the key of C major starts on the 7th fret is coincidental. For example, the 7th pattern of the key A major starts at the 4th fret, because that is where the 7th note of the key of A major - G# - is located.
We'll be using alternate picking for this, and almost all exercises I show you (unless noted otherwise). After you get these exercises down, do them with all seven of the diatonic patterns, not just the one I use for an example here. You'll find that some are easier than others, and some have cool little sections that are easier and more useful than others.
And actually, you should use the following three exercises - and any others you figure out on your own, learn from other players, or read about in future editions of this column - on ALL scales you ever learn. It will make it much easier for you to turn scales into solos, and that's what it's all about, right? It's an endless road of learning folks, but it's an enjoyable road just the same.
Exercise 1
Exercise 1 is a four-note pattern.
Practice Point 1: Play B at the 7th fret on the sixth string with your first finger, using a down-stroke of your pick. Then play C at the 8th fret with your second finger and an up-stroke of your pick. Play D at the 10th fret with your fourth finger and a down-stroke. Then finish the first four-note pattern by playing E at the 7th fret on the fifth string with your first finger and an up-stroke. But wait, we're just getting started.
Practice Point 2: Now play C at the 8th fret with your second finger and a down-stroke of your pick. Play D at the 10th fret with your fourth finger and an up-stroke. Then play E at the 7th fret on the fifth string with your first finger and a down-stroke. And then play F at the 8th fret on the fifth string with your second finger and an up-stroke.
See how this pattern goes? You play four notes up the scale, then jump back three notes and play four notes up from there. Repeat this pattern until you reach the top note on the first string in the pattern you're working on (in this example, the 7th scale pattern in the key of C major, starting on B.)
Practice Point 3: Then reverse the whole thing: Play D at the 10th fret on the first string with your fourth finger and a down-stroke. Then play C at the 8th fret with your second finger and an up-stroke. Then play B at the 7th fret with your first finger and a down-stroke. And then play A at the 10th fret on the second string with your fourth finger and an up-stroke.
Practice Point 4: Then, of course, jump back three notes (to the C at the 8th fret on the first string) and move down the scale four notes. Repeat that pattern until you end up back on the B at the 7th fret on the sixth string.
Extra Tips: For optimal results, slide this exact scale pattern down to the first fret on the guitar (which would put you in the key of F# major), play up to the first string and back, slide up one fret (putting you in the key of G major), and repeat, etc. Slide up one fret at a time and repeat the pattern until you just can't take it any more, and you want to smash the guitar through the nearest computer monitor (WAIT! Bookmark this page first!)
This pattern is actually very common in the lead guitar solos of many rock guitarists. Of course you'll never want to use more than two or three groupings of four notes at a time - you wouldn't play all the way up and/or back down the six strings using this exercise. That would sound like a, well, it would sound like a scale exercise.
But if you listen closely to your favorite soloist, you'll catch them using this riff from time to time in smaller chunks. Work it out and make it your own. And remember to start slow and clean, and only increase your tempo when you can play the pattern without mistakes and flubbed notes at a slower tempo. Use a metronome, drum loop, or drum machine to set and change the tempo.
Exercise 2
Exercise 2 is a three-note pattern, and is played using the same up and back formula as exercise
Practice Point 1: Play B at the 7th fret on the sixth string with your first finger, using a down-stroke of your pick. Then play C at the 8th fret with your second finger and an up-stroke of your pick. Play D at the 10th fret with your fourth finger and a down-stroke.
Practice Point 2: Now play C at the 8th fret with your second finger and an up-stroke of your pick. Play D at the 10th fret with your fourth finger and a down-stroke. Then play E at the 7th fret on the fifth string with your first finger and an up-stroke.
Practice Point 3: Play D at the 10th fret with your fourth finger and an up-stroke. Then play E at the 7th fret on the fifth string with your first finger and a down-stroke. Then play F at the 8th fret on the fifth string with your second finger and an up-stroke.
Extra Tips: So you see, this is three notes up, two notes back, three notes up, etc. And of course you'll want to practice it going down the scale from the top string as well. The key to this one is truly alternate picking, because it gets really tricky if you don't have your alternate picking down. But you know what? You will have your alternate picking down after you do this one! When I play this exercise, I seem to fall into a rhythm that includes a slight pause after each three notes. That helps me to separate each grouping, and probably helps me keep the picking alternating.
Exercise 3
Exercise 3 is a five-note pattern, and is played using a similar up and back formula as exercises 1 and 2. However, in this exercise, we'll go five notes up, then jump back three notes, then go five notes up from there.
Practice Point 1: Play B at the 7th fret on the sixth string with your first finger, using a down-stroke of your pick. Then play C at the 8th fret with your second finger and an up-stroke of your pick. Play D at the 10th fret with your fourth finger and a down-stroke, then play E at the 7th fret on the fifth string with your first finger and an up-stroke. Finish the first note grouping off with F at the 8th fret on the fifth string, played with your second finger and a down-stroke.
Practice Point 2: Now jump back three notes and play D at the 10th fret on the sixth string with your fourth finger and an up-stroke, F at the 8th fret with your second finger and a down-stroke, and G at the 10th fret with your fourth finger and an up-stroke. Finish this note grouping off with A at the 7th fret on the fourth string, played with your first finger and a down-stroke.
Extra Tips: So you've got five notes up, three notes back, five notes up, etc. And again, you'll want to practice it going down the scale from the top string as well. Now this exercise actually starts to sound more like a real solo and less like an exercise. Just make sure you practice is slow and clean before you speed it up. Fast, crappy playing is not as cool as slightly slower, accurate playing.
That's It, Doggy!
Enough for now. These exercises should keep you busy for, oh, say, the next 25 years or so. That's how long I've been workin' 'em, and they've served me well. In terms of agility, accuracy, speed, and simply feeling good about my playing, exercises like these work miracles. Go for it