Playing the guitar is a personal experience. You evaluate a guitar with your eyes and ears, and most importantly, how it feels in your hands (a few of you will even use your senses of smell and taste). In addition, there are substantial objective differences, not only between brands and types of guitars, but among samples of the same guitar (i.e., same manufacturer, year, model and options). Selecting an instrument can be a time-consuming and frustrating experience, compounded by price considerations, your level of expertise as a player, your ability to evaluate the instrument, and the possibly rapacious nature of the seller. At the risk of contributing to the general noise in your head, I'll try to provide a few points of reference for evaluating the guitar. This is primarily an acoustic guitar forum, so I'll channel the discussion in that direction, but many of the fundamentals will apply generally.
What Kind to Buy?
I can't say. I have plenty of opinions, naturally, but I don't think there's reason to be dogmatic. For the flattop steel-string , the Martin D-28 is a benchmark of sorts, and it's true that the overwhelming majority of lower-priced (and many high-end) flattops are a copy of the D-28 design. For bluegrass players, and many folkies, there may be little reason to look further (or maybe only as far as an OM type for you finger-style guys). But it's likely that the sound you want is dictated by what's used in the music you like, and by the sound of the players you admire. If, for instance, you want the sound of Beatles' rhythm parts, you need the tubbier and somewhat boxy sound of a Gibson flattop, and even a very good D-28 won't quite be convincing. And if the recorded sound of a good Martin appeals to you, done expect to get that sound from a $150 imitation, however similar it seems visually.
Other flattops have a characteristic sound that derives from the marriage of acoustics and electronics (If it's a Gibson J-60E that John Lennon's using, some of that tone is coming from the magnetic pickup fitted at the neck). The Ovation, the original Takamine, and an array of 'stage' acoustics have penetrated the market with their ability to function well (i.e., not feed back too much) in relatively loud stage situations. With repeated widespread use, the tonality becomes familiar, then acceptable, then perhaps desirable. But a good proportion of that familiar sound comes from the tonal color of the guitar's electronics (the piezos, the frequency response of the preamp, or both), and may be unsatisfying to you as an unamplified acoustic instrument.
So it's very important to know what use you'll make of the instrument. A lightly-constructed and responsive guitar can be a joy in the bedroom or studio, and a nightmare on the road. When you've heard a great guitar sound at a live show, you can be sure that another large chunk of money has been spent to manage and shape the sound between the guitar and your ears, both to control feedback and to reshape the less-than-transparent guitar electronics, amplifiers, speakers, and room ambience. Lightly-made instruments can be less road-worthy as well: Changing temperature and humidity may cause small annoyances, such as the tuning changing with the heat of stage lights, or bigger problems such as cracks or sprung braces. If you're not getting that great sound from the sound system, you may wish you'd left it at home in favor of a sturdier and less-responsive instrument. On the other hand, if the use of the guitar will be truly acoustic, or amplified with microphones in the studio, by all means go for all the tone you can afford.
Selecting a classic guitar is at once simpler and more problematic. There's more general agreement about what a good one should sound like, and thus more consistency in design (body shape, depth, bracing scheme, etc.), stemming from the original Torres design. The classic playing technique also dictates a fair amount of uniformity in the 'feel' of classics (longer scale length, wide nut width, flat fingerboard, characteristic carving style of the neck). A notable exception involves players who want a 'crossover' guitar to play another style on a nylon string. The Ovation classic (and some Gibson Chet Atkins models) is popular with jazz players looking for a nylon string: The shorter scale, narrower nut width and radiused fingerboard present less of a departure from other instruments they own, and require less adjustment in technique. If that's where your intent lies, your choices are more limited.
Though there is much similarity in classic design, I don't want to imply that a $150 polyester-laden plywood classic will compare with a high-end instrument. But once we've got the correct materials and finish, the distinctions can be fairly subtle. Most classic players I've spoken with, players who've owned many instruments, have agreed with me that a particular example of a $700 classic and a particular example of a $2000 to $3000 classic may be similar enough in tone (or their positives and negatives pretty much in balance) that the distinctions can't justify the price difference. They also agree that spending many thousands (or tens of thousands) for a handmade instrument may give you the volume, balance and sweetness of a truly remarkable instrument, and that you can get burned even at those prices.
Archtop guitars are likely the most difficult to pin down. There's not much agreement, as far as I can tell, about the sound we're going for, much less box size or other construction features. For most players a large component of the sound is electronic, and there is huge variation at the amplification end, from tiny tube amps to elaborate quasi-P.A. set-ups, and often lots of signal processing. Even at its simplest, there will be heavy interaction among the acoustics of the guitar, the pickup(so), and the amplifier. I'll leave it at that for now, since the archtop deserves its own extended treatment.
For the true beginner: I would urge you to concentrate on ease of playability when shopping for a guitar. It's impossible to produce good tone without decent technique, so the priority should be to avoid the frustration that will prevent the development of that technique. Teachers will often send their beginners to me to put their guitars in shape, and often the work request reflects the teacher's perspective more than the beginner's needs: Let's go to heavier strings for a better tone; or raise the action for a buzz-free attack. But beginners will produce plenty of buzz with no help from the guitar, and a higher action may just mean that they'll tire more easily and put in less practice time. So by all means look for low action, and use lighter strings if it means you'll play more. You'll know when it's time to concentrate on getting good tone.
New or Used?
Hard to say. Music stores can be great places to compare different brands and models, and if you know exactly what you want, there will hopefully be a few or several examples of the same guitar model. If the environment is quiet (and that includes the salespeople), you may be able to make an intelligent decision. A very large plus is a store policy that allows for a no-questions-asked return; a week is okay but thirty days is great (and it should be a refund, not a store credit). In any case, you need enough time to evaluate it yourself, in your own environment, have a friend or other experienced player evaluate it, and have someone like me evaluate it (most of us won't charge you if you don't waste too much of our time). Other players can tell you what they like or don't like, usually in an impressionistic way, but most of them can't tell you about possible problems, trivial or catastrophic, that may lie in wait for a given instrument.
The guitar's warranty, as salespeople will tell you, is your protection against such problems. But the ugly truth is that very few companies (Martin is one) will make your satisfaction the first priority. More often, they will make the only determination of whether the condition or playability requires serious repair or replacement. And it is, by and large, not the fault of the retailer, or its repair department. A typical scenario (and I've been inside it) goes something like this: You've purchased a guitar, have asked to have the action lowered to your preference, and now find the fret buzz unacceptable. Perhaps the neck has a poor contour (a twist, s-curve, or hump), the source of the problem. The warranty repairman, if competent, may see that only planing the fingerboard, with attendant refretting, will make the guitar play at the action you want. But the manufacture's reimbursement schedule pays laughingly little for that kind of repair , which takes many hours. What should the repairman do? Recommend returning the guitar to the manufacturer, and a replacement or refund for you. The store owner now has one less guitar to sell, and must wait for the manufacturer to determine if the return was justifiable, along with the attendant hassles of communication, paperwork, and shipping. And it's true that the manufacturers can take a hard line if you’re throwing too much product back at them. So the incentive is for the store to do a less time-consuming (and less satisfying) repair, and hope that you're happy, or at least not too unhappy. Too often it turns into a war of nerves: The squeaky wheel gets the grease, or goes away squeaking. As weak as most warranties are, in this context, they're weaker still if the time limit is too restrictive. Poor neck contours may not show themselves until the neck has gone through a few seasonal changes, and premature neck angle problems rarely show themselves before a year or two, so a one-year warranty likely won't cover the more expensive calamities. If it’s a limited life-time warranty, be sure to take note of what falls under the 'limited' description, and what you have to do to satisfy the terms of the warranty. A good repairman can often see the serious problems coming, but most guitars will have their little surprises.
A new guitar is just that: It's new, and if sensitively constructed, will not sound the same after months or years of playing. Often that's all to the good, a somewhat thin and stiff guitar opening up to be louder and more responsive. But it's also possible for a guitar to go south as it opens up, perhaps losing definition in the upper frequencies, developing an annoying bump in the midrange frequencies, or having the bottom end turn to mush.
So why not buy a used guitar? It's been played in by someone else, and you can be more confident of the tone. I'm all for it in general, but be advised that it's a lot more work. There are fewer samples of the same guitar model to be found at the same location, and if your shopping through the want ads, sometimes many miles between guitars. But there are genuine bargains to be had, especially in guitars not avidly sought by collectors. Guitars sold by Yamaha, Aria, et al, in the '60's and early '70's, before they established themselves in the American market, are often very close copies of good guitars (both flattop and classic), made of good materials, lightly constructed, and thinly finished. And most models of Guild flattops are to be had for reasonable money, not having been deemed collectible at this point.
Most of these guitars have also been around long enough to develop more or less serious problems. If buying a used guitar from a store, the return policy will again be of utmost importance. If from a private party, do your best to get agreement to have the guitar examined before the deal is finalized (yeah, I know, but it does happen). If the guitar sounds good enough, and the money is short enough, you may need to reconcile yourself to including major repairs in your idea of the selling price. I have, for instance, done $500 or more in work on guitars that originally sold for less than $100, and while I've felt a little odd about it, the rehabilitated instruments became worth much more than that in tone and playability, if not necessarily in resale value.
Up to the middle of this century, tone woods for guitar construction were relatively cheap and plentiful, and except for very low-end instruments, you could take for granted a few constants. Guitar tops would be solid quarter-sawn spruce, backs and sides of solid rosewood or mahogany, necks of quartered or very straight flat-sawn mahogany (In the case of classics, spruce or cedar for the top, cedar or mahogany for the neck). In any case, all solid materials, and pretty straight-grained.
As supplies shrank, and guitar production rose, something had to give, and that something has a lot to do with how much you'll spend for tone. Laminated woods (plywood) began to be used, both for cost savings and the expectation of greater stability (i.e., greater stability than a suspect cut of the more traditional woods). Plywood first appeared in the sides of the guitar, later the back, and finally the top. The first plywood top materials, in low-end acoustics, were similar to construction plywood (and I don't imply that their not still being used). The veneer-like laminations were cross-hatched, the grain of one layer running at an angle to the next, perhaps with a paper-thin top veneer to give the appearance of a guitar top. The construction emphasizes strength but not resonance, since the opposing grains are not disposed to vibrate in any particular direction.
But if we're looking at solid woods all round, and closely similar structural design, we can roughly characterize the resulting tone according to materials. With the back functioning as a secondary resonating plate, and as a reflector for top vibration, the usual woods line up as follows: Maple will be bright, rosewood fairly bright but producing better bottom, and mahogany the darkest, sometimes not reproducing good high frequencies. The more recent substitutes, such as koa, walnut or paduak, will fall somewhere between rosewood and mahogany in response.
Spruce is the overwhelming choice for solid-top steel-string guitars, and perhaps deserves a bit deeper discussion. High-end guitars will frequently use expensive Alpine spruce, which may be referred to as European, German, Bavarian, etc.,which is quite white in color and an excellent tone wood. Eastern spruce of the U.S. is similar to Alpine, but due to dwindling supplies is now also quite expensive. Engelmann spruce, logged in the Rockies, has better availability, as does Sitka (Alaskan) spruce from the west coast of the U.S. If the type of spruce is not specified you can likely assume that it's Sitka, especially in a factory-made instrument. I think that any of these spruces can be fashioned into an outstanding (or poor) guitar top, and offer them mostly as a means to dissect the sales pitch. Cedar (Western Red Cedar) and redwood have more recently been used for tops, and though design and execution will dominate as it does with spruce, you will hear an objective tonal difference. Cedar and redwood will sound darker than spruce (they're softer woods), and, other things being equal, will break in more quickly. You will have to try to project the tonal changes in the guitar after it's played in. A well-made spruce-top guitar probably should sound a bit thinner and less resonant than you'd like, because you know (or hope) that it will open up later. Conversely, a redwood or cedar top can sound a little too good initially (and that helps the store to sell them), but may become mushy in the bass and weak in the treble after a couple of years.
As we descend across the Mendoza line for guitars (in the $600-800 range), plywood abounds, and presents less confusion about how the guitar will break in. The original plywood top, vibrating in no particular direction, has no consistent long grain that will become more flexible when stressed, and so gains little in bass response over time. So if you like the initial tone, you can count on no drastic changes. A more recent approach to plywood, fabricated with guitars in mind , arranges the veneers with the grain running in the same direction, a closer imitation of solid wood. The result more easily resonates, but the interpolated layers of glue, along with variation in the grain of the veneers, will prevent a large improvement with age. Nonetheless, it will open up a bit, and the overall tone is a big improvement over the old plywood. A third variation, found in inexpensive guitars, is more devious. Most of the thickness of the top is solid wood, but of inferior wood and sometimes of several pieces, joined lengthwise. A beautifully patterned spruce veneer is glued over the face, and to the casual eye it appears a fine solid top.
The large manufacturers will offer vague descriptions of the woods in their literature. If they're using solid spruce, you can be sure they will tout it as solid spruce. Otherwise, they will simply say 'spruce,' and you should assume some sort of laminating is going on. The way to determine what you've got is to examine the endgrain of the top, which you can see at the lip of the sound-hole. If the lip is painted with a solid color, you can assume the nasty old-style plywood is under there. If you can plainly see the layers, you know it's plywood. If the mostly-solid-but-bad-wood approach is used, you will have to determine that the spacing of the vertical grain lines doesn't match the spacing of the beautiful surface veneer. In the laminated top, where the veneer layers are oriented in the same lengthwise direction, and if well fabricated, you'll need very close inspection, and perhaps a practiced eye, to discern the layers. But all things considered, once you've found that the top is laminated, make sure that you're happy with the tone as it is, or continue your search.
The back and sides are lesser contributors to the guitar's tone, and I don't have much of a problem with laminated sides in any price range. The back is more important, but if a long-grain lamination is used, it may not be a significant deterrent. The materials of which the neck is made will contribute to tone on any guitar, but for individual necks of comparable stiffness, the difference will be of subtle coloration. In flattops and archtops, the neck will usually be mahogany, occasionally maple: The greater density of maple will generally produce a brighter tone; the softer mahogany will allow more end-to-end vibration of the instrument, and so will be darker. In classics, mahogany dominates as well, but because of the lighter string tension a less-dense alternative (Red Cedar) is often used, giving a softer tone and better weight balance. The choice of fingerboard wood, almost always ebony or rosewood, has an additional tonal effect, more subtle yet, the high density of ebony giving more brightness (or perhaps clarity) than rosewood. But many players will be attracted to one or the other by the feel of their fingers on the wood, the smooth and somewhat slick ebony versus the open-grained and resinous rosewood, and make the argument for tonality after the fact. Brazilian rosewood, now rarely available for use in solid backs and sides, can show up in fingerboard use, and is my personal favorite in feel and tone.
The woods of the guitar need protection. Acids, oils and moisture (all of these oozing from your pores) will discolor and eventually degrade wood, and can undo glue joints. Additionally, the finish functions as a moisture barrier, of varying efficiency, to buffer the effects of humidity changes. We need to coat the wood with something, and whatever it is , it should be thin. Traditional finishes include shellac (bug resin), varnish (gum resin), and nitrocellulose lacquer (glorified cotton). More recently, acrylic lacquer, catalyzed lacquer, polyester, or polyester/urethane combinations are favored, for reductions in both labor time and environmental emissions. Any of these can be used effectively, but often aren't, since the reduction of labor costs is 'job one.' The traditional finishes take many hours of sanding, re-sanding, rubbing and polishing; some of the newer finishes harden almost instantly, and often the only leveling they get is at the buffing wheel. The result is unnecessary finish thickness on many production guitars , and even on some from small builders. You can view that thick finish as a lamination, serving to damp the vibration of the top and back. Thick finishes are to be avoided, and there is enough variation from guitar to guitar that it's worth your while to develop an eye for it.
Some manufacturers, and most small builders, will make an effort with the film thickness on the top of the guitar, and some will even use a different finish on the top to preserve its flexibility. Some Pacific Rim manufacturers use a flat (matte) urethane on the top (as on some Takamines), the rest of the instrument lathered in the usual thick and glossy polyester. This is a positive trend, and I'm sure you can hear it in the tone, since the urethane is much less brittle; it would be fine with me if they used it on the whole instrument. The manufacturers think, however, that the high-gloss mirror finish helps sell guitars, and for the bulk of their market, they're probably right.
It will be difficult for you, indeed its difficult for many who are in the business, to pinpoint details that contribute to the tone of an instrument: Box design, materials and finish all work together in concert, or at odds, with one another. Most players, in fact, can't articulate what it is about a guitar neck that gives them comfort, or drives them away. And often enough the player's perception of playability can cloud or overwhelm the perception of tone. But making an effort to deconstruct the whole can allow you to make objective judgments, which will inform your subjective judgments, and hopefully save you some valuable time in selecting an instrument. Just as a used-car dealer, when you've voiced concern about the clouds of blue smoke emanating from the tailpipe, will say 'It just needs a tune-up,' people who sell guitars are fond of saying 'It just needs a set-up.' Guitar retailers make no money (in fact it costs them money) to set up an instrument to your satisfaction. Inasmuch as the poor set-up may be masking more serious problems, it's reasonable for you to ask, as you might of the car salesman, 'If it's such a trivial matter, why don't you take care of it?' Now, you may be a trouble-maker yourself, or demanding to the point that no standard of playability is high enough, but in general I think you're within your rights to have the instrument play as you want before you permanently part with your money (again, the no-questions-asked return is very important). And if you're spending a substantial amount of money for a used instrument, it's reasonable to ask the seller to have a set-up done before you buy, even from a private seller.
Guitars, even new ones, can have serious problems, with expensive remedies, that are only acceptable if you're aware of them, and have included the cost of the remedy in the amount you're spending for the instrument. Some can be disguised by the set-up; some are unrelated to the set-up but are a factor in the tonality of the guitar.
Neck and frets: Large guitar factories go through lumberyard-size shipments of woods, and they have the tendency to want to use every last bit of it. The perfect neck is a quarter-sawn cut, of good strength, and with density that's consistent along its length. A neck that's not particularly stiff will have difficulty standing up to the tension of the strings (typically 135-175 lbs. for a flattop, depending on string gauge), and may need a lot of extra support from the truss rod inside the neck. The one-piece compression truss rod, which is most widely used, has the unfortunate side-effect of squeezing the neck lengthwise as it forces the neck straighter. When the neck has different densities along its length, this compression produces humps and dips in the even curve you'd like to see, irregularities we affectionately call an 'S-curve,' or the dreaded 'double-S-curve.' Unrelated to the action of the truss rod, necks also have a tendency to compress in the area where the neck joins the body, causing a hump at that point (on guitars that have been around for several years, this one is less a manufacturing defect than a 'fact of life'). Other necks, which may be acceptably stiff, may have an uneven grain pattern which causes them to hump or twist with no collusion from the truss rod; yet others are too stiff, only dimly aware of the tension of the strings, and may settle into a contour that's too straight or convex (back-bent). Any of these irregularities can range from trivial to severe, and all can be masked, somewhat or entirely, by a high action. The remedies could include an improved set-up, light and perhaps localized fretwork, heavy fret leveling, heating the neck along with fretwork, or planing the fingerboard and refretting the instrument. And the cost can range from $50 to $500 or more.
Distinct from neck contour problems, irregularities in the heights of frets, from one to the next, will cause buzzing, and again can be masked by a high action. On new guitars, the differences in fret heights is usually caused by individual frets not being as well-seated against the fingerboard as others; the frets may be poorly leveled with one another after the fact, or perhaps not leveled at all. Fretwork is one of those hand-labor jobs that drive up production costs, and the factories are always trying to quicken the process. In general, the seating of frets is done more consistently than in the past, but in the last few years I've noticed a disturbing number of loose or sprung (popped-up) frets on new instruments. If the fret slots in the fingerboard are enlarged slightly, the frets can be installed more quickly, but depend more on glue than friction to hold them in place. The fingerboard wood will swell and contract with humidity, the glue joint will fail, and sooner or later the fret will loosen. If the fret is not perfectly arched to match the fingerboard, the fret will pop up, most often at the ends. Loose frets are problematic even when they aren't sprung. The loose fret will vibrate along with the string, soaking up sustain at best, and at worst producing a sitar-like 'wang' that's often confused with fret buzz. And loose frets can't be successfully leveled; they'll move and chatter under the flat file, and the usual result is just to loosen more frets. The remedy is to remove and reseat all the frets, or replace with new frets, but the store owner will likely prefer that the repairman do a quick fix, e.g., gluing down the fret ends, and that will just postpone the problem for a few weeks or months. Again, the best solution is to return the guitar to the manufacturer, and it's done not often enough. Used guitars may well have the fret problems I've described, or perhaps only fret wear: flat spots or grooves from repeated contact with the harder steel string. If the frets have sufficient height to be filed and recrowned, add to your purchase price a few hours of a repairman's time (perhaps $90-135). Bear in mind that a full refret may be necessary, and expect to pay $200-300. The Neck Angle: A goodly portion of the volume and tonal quality of a steel-string or classic is generated by a torquing (rotational) motion at the bridge location. There are design theories to the contrary, but most of the guitar tops you'll run into have been tuned (in terms of top thickness and bracing scheme) with a certain amount of string height (the distance from the surface of the top to the string) in mind. The thickness of the bridge, and the angle of the string from the saddle top to the point where it's tied or pinned (determined by the height of the saddle above the bridge), will add up to the torquing force. The builder's design will expect that height and angle to remain the same for good tone production, i.e., full bridge height and a saddle projection of 1/8-3/16 of an inch (~3-5 mm).
The forces produced by string tension are hard on the area where the neck joins the body, and it's common for the neck, after a few or several years, to tip in toward the body. The distortion can be caused by the neck flexing forward at the point where it's carved down to size at the heel, e.g., the 12-14th fret area on a steel-string, the 10-12th fret area on a classic. This we sometimes call 'flagpoling,' as a flagpole will bend at the point it exits the ground: It bends where it can. Secondarily, the stresses of string tension can cause moderate to severe distortion of the shape of the top and sides, at the neck/body joint, allowing the neck to tip forward into the body. The bottom line, whatever the cause, is that the neck joint was designed to angle back from the body, to set that string height at the bridge, and that angle has become flat, or even negative.
An incorrect neck angle sometimes appears in new guitars, which we can attribute to a poor fitting of neck to body, but it's more likely to show up in a used guitar, and the angle will usually have changed gradually. As the angle changes, the action of the guitar will get higher, and for a while the saddle height can be reduced to restore a good action; eventually the saddle height is as low as it can go, the guitar has lost tone and volume, and the action is still uncomfortably high (and getting higher all the time). The rule of thumb we use involves sighting along the edges of the frets, from the peghead end, and pretending that the sight line from the 1st to 14th frets is an imaginary line (if it has such a large curve, or so many humps and dips that you can't imagine the straight line, that's something else to feel queasy about). Anyway, sight the line, and visually extend the line to the point where it contacts the bridge. The line should hit the bridge at its top surface. If it hits a point more than a couple of millimeters or so down the side of the bridge, toward the top, the neck angle is incorrect. If you lack confidence about your ability to see the angle, you'll have to let the playability tell you: If the action is too high, and the saddle too low, you'd be smart to get it evaluated.
For a steel-string, using a dovetail joint, the repair is major, but it’s done all the time. The neck joint must be steamed apart, the dovetail and heel reshaped, and the joint reassembled at the proper angle, often with minor fretwork at the joint area (expect to pay $250-300). Classic guitars have, by and large, a Spanish-style neck joint in which the sides of the guitar enter into slots cut in the neck itself. The repair involves exploding the guitar to a large extent, costs many hundreds of dollars, and you should think long and hard before deciding that the quality of the instrument justifies the expense.
Archtop guitars will suffer neck angle problems as well. In this case, the progressive lowering of the saddle doesn't have to do with torquing, but rather reduces the down-pressure of the bridge, changing the tensioning of the top. Eventually, the action can't be lowered enough, and with some exceptions, it's not a good idea to reduce the height of saddle or bridge base. But archtops use dovetail joints, and the angle can be reset in similar fashion to the flattop, though the job is a bit more elaborate.
Body Structural Problems: The stresses of string tension, and temperature and humidity shocks, can cause cracks to top, back, and sides, and glue joints to let go. Cracks should be repaired, of course, but they may or may not distort your impression of the sound of the guitar. They should be evaluated individually, and the cost can be trivial or significant, depending on the location of the crack and your interest in cosmetic (finish) repair. A bridge that's separated or lifted from the top of a flattop or classic is not usually a cause for great concern, but the strings should be loosened and the repair done as soon as practical, because all those pounds of tension are busy warping the rear of the bridge and trying to rip it free of the top. Expect to pay $90-130 for a good bridge reglue.
Players are usually concerned about plate cracks because they can see them readily. But cracked, broken, or separated braces, especially on the underside of the guitar top, are more likely to give a misleading impression of both tone and volume. Builders wouldn't use bracing or any other reinforcement if the wood would survive without it. If one or more braces become separated, the top can sometimes vibrate more freely, sounder bigger and louder, at least up to the time the top collapses. I've been in the uncomfortable position of repairing braces that had been loose or separated for some time, and the owner had become accustomed to the sound. The repaired guitar, once again structurally sound, now sounds a bit thinner and quieter. So it's important to poke around inside a guitar that you might buy, and to tap-test it all over, because there's a possibility that it sounds better than it has a right to.
Other fairly trivial items should be noted. Not catastrophic in themselves, the repair costs can add up: Worn machine heads (tuning machines), a worn or cracked nut or saddle, wear-damage to the bridge pin holes or underlying bridge plate, a lifted pick guard. For an archtop, the above apply, as well as electronic work, and possibly shaping the underside of the bridge base to mate well with the top (very important, tonally). Body buzzes (rattles or zzzzt sounds) are a common complaint with archtops, and if the noises don't originate in the body itself, the repairman may still spend a fair amount of time securing and padding all the stuff attached to the body: Pickup and attendant hardware, raised pick guard, controls, cables, bridge pieces, etc. Make note of the small stuff and get an estimate for repair. You'll have to deal with them sooner or later, and it makes sense to include them in the price of the instrument.
Amplifying an acoustic instrument merits a full-scale discussion, which I won't get to here. Flattop guitars can be amplified with a few different transducers: a magnetic sound-hole pickup, a contact piezo, an under-saddle piezo, miniature electret condenser microphone(s), any and all. Classics will function with all but the magnetic, not having ferro-magnetic material in their strings. Archtops are usually amplified by magnetic pickup, but occasionally with bridge piezo or microphone as well. And of course all are effectively amplified with a full-sized microphone in a controlled environment, such as the studio or a small stage act. None of these methods is completely transparent. A studio condenser mike comes closest, but these are not always used by themselves, even in studios: The coloration of the other devices is often part of the sound we want from a particular instrument, i.e., transparency is not always the only goal.
As a retrofit, you will generally spend the least for a contact piezo or a magnetic (except perhaps for you Sunrise owners), generally $30-100, and installation costs are modest as well. Under-saddle piezos range from $70-140, and the labor can vary a bit. The saddle piezo depends upon a solid 'sandwich' of saddle, piezo pickup, and bridge slot, and I will usually want to re-rout the saddle slot (don't try this at home) to provide a good foundation for this sandwich. Earlier (and some current) saddle piezos are constructed of six individual piezo crystals, and a loose sandwich structure results in poor string-to string balance. The newer versions are usually a continuous piezo material, most often piezo film. While you're less likely to get string balance problems, a poor installation will give you less presence and transparency in the amplified tone. Also, some saddle materials can function better with the pickup, and the saddle should be replaced when indicated. Expect to pay $100-180 to get it right.
I don't recommend that any piezo be used without a buffer/preamp. Piezos are very high impedance devices, in electronic terms, and connecting them to lower-impedance devices (like a guitar amp, most effects devices, or passive volume and tone controls) is an impedance mismatch, and will result in some loss (or big loss) of bass response. I should point out that some of the amplifiers designed for acoustic guitar take care of this problem with a buffer at the front end of the amplifier. Several of the available piezos, as well, include a buffer as part of the package. If not, you'll need to add one, either in the guitar or in a separate box, to get the sound the piezo has to offer.
Electret condenser mikes vary hugely in price, from $2 at Radio Shack to $250 or more. Installation is not difficult, but much time can be spent locating the microphone within the guitar, to get the best response with the least feedback. I've had the best luck with more directional microphones (hyper-cardioid or cardioid, as opposed to omni), but I will usually recommend them only when the player is committed to good sound reinforcement, as there are lots of frequencies bouncing around inside the box that we’d prefer not to hear. This may mean some fairly expensive equalization dedicated to processing the microphone, or a full-blown P.A. controlled by someone with good ears.
There are several electret/saddle piezo packages available, but I don't recommend them, even if you have the full-blown sound system, unless the electret and piezo can exit the guitar separately. The piezo and microphone require different equalization curves to get the most from each: tying them together for a single output will simplify your controls and connectors, but it won't give you the opportunity to shape the sound of either to best advantage. When buying a new guitar, you should consider your electronic needs. If you're interested in a Takamine, for instance, and you like the usual Takamine amplified sound, it makes no sense to later add (at great expense) the Takamine electronics to the acoustic version of that guitar. When the sound of the guitar you want has significantly to do with the sound of its associated electronics, it is always cost-effective to buy the electronic version of that guitar.