beginner amps, starter amps, student amps, call them what you will—the small, low-wattage tube amplifier has been with us for many years, and guitarists today know them for the little tone machines they are. Gibson’s entry in this category has been one of its longest running models, making its original run from 1954-’67, and appearing again in 2004 as a reissue model. The diminutive GA-5 was originally released when Gibson needed a small partner amp to accompany its Les Paul Junior guitar, introduced in 1954 as the company’s first solidbody “student” model. Although its circuit and appearance evolved over the years, it has always retained its unfettered tonal purity. 

Although it had offered a handful of acoustic and electric guitars at “entry level” prices in the past—at the entry level, that is, to the higher end of the market—Gibson had never been a major manufacturer of what could be called “beginner’s instruments”. The success that other amp makers like Fender and Valco were having with entry-level equipment couldn’t have gone unnoticed, however, and taking a stab at that lower end of the market made sense on many levels. While Gibson’s amplifier program, with Seth Lover at the helm, was turning out some of the most advanced larger amps of the day—though still chasing Fender’s dominance of the market—a small amp like the GA-5 didn’t require any great thinking. The original model carried a single 8" speaker (for a time, a 7" oval speaker), just one knob for Volume, and a mere 15 resistors and capacitors in its circuit. Using just one tube in each category, a 6SJ7 preamp tube (a rather unusual 8-pin pentode), a 6V6 output tube, and a 5Y3GT rectifier tube, it produced a whopping 4 watts. 

That output level doesn’t look very impressive on paper, but cranked up in your bedroom, or in the studio in front of a good microphone, a good GA-5 is capable of belting out some righteously juicy tones. And although Gibson usually designed its amps to be cleaner than comparable Fender models, a simple booster pedal can kick a GA-5 into scorching overdrive. Pentode preamp tubes like the 6SJ7 (a cousin of the GA-40’s 5879 and of the EF86 that Vox often used) have a fat, creamy tone that really drives an output stage well when you wind it up, but usually resists tizzy, frizzy sounding distortion at the same time. And to most players who make use of them today, the GA-5’s low output is a boon, rather than a fault. While would-be guitar heroes throughout the ’60s, ’70s, and ’80s were chasing the big stacks that their idols were playing live, these idols were frequently recording with small combos bearing output levels in the single digits. Get a little GA-5 up into the sweet spot, and you can achieve a sizzling, slightly compressed, and very touch-sensitive tone without riling up your house mates, or your sensitive studio microphones, and often you’ll achieve much more satisfying results than can be had by reining in an over-sized amp.

The GA-5 and its ilk are also noteworthy as examples of true class-A amps. A lot is made of the “class A” designation (which describes an operating class of tube amps, not a quality assessment such as “grade-A beef”), and it’s too technical a subject to explain thoroughly in the space allowed here. Suffice to say that many larger amps described as “class A”, those with two or four output tubes, are really cathode-biased push-pull amps that might be operating in class A if you got them up on the bench and assessed them with the right equipment, but are more likely to be operating in class A/B for much of the time. As this operating class is defined by output tubes that remain on throughout the full wave cycle (while each of the paired tubes in most push-pull amps shut down for a brief portion of the cycle), only a single-ended (ie single-output-tube) amp such as a GA-5 can be undeniably class A, since it’s one 6V6 never shuts down. If all that runs a little technical for you, boil it down to this: good single ended amps undeniably produce the sweet breakup and juicy harmonic saturation that some players seek in other supposedly “class A” amps, and they do so by their very nature.

Throughout the ’50s and much of the ’60s the GA-5 evolved through a range of incarnations, each of them interesting in its own way. The GA-5 Skylark of 1958-’62 swapped the 6SJ7 for a 7025 (aka 12AX7) preamp tube, but remained largely similar to its predecessor. In 1960, Gibson also added a GA-5T with tremolo to the family, and this amp now used two 6EU7 preamp tubes and a single 6AQ7 output tube (a cousin of the EL84), with a small 6X4 rectifier tube.