When Swart decided to split their Atomic Jr. five-watt combo into a piggyback, they not only went from an 8″ speaker to a 12″, they added more speaker options, including the Mojotone BV-25 and Celestion’s Creamback 75, Cream Alnico, Anniversary, G12 Blue (as tested), and Alnico Gold.

The resulting all-tube Atomic Jr. head features an Electro-Harmonix 6V6GT power tube, a JJ GZ34 rectifier tube (5Y3 also available), a JJ 12AX7 preamp tube, and a JJ 12DW7 for the reverb. Head and cab are finger-jointed pine; the circuit is point-to-point hand-wired with cloth-covered wire and uses CTS pots, Switchcraft ¹/4″ jacks, American-built transformers, carbon comp resistors, and Mallory capacitors. Controls are basic: Volume, Tone, Space (reverb), and a hidden “set it and forget it” Clean/Hot switch atop the chassis.

The overtone-saturated Atomic Jr. offered chimey top-end, punchy round bass, and thick perky midrange responsive to pick and finger attack. With the gain set to Hot, the front end was easily tickled into rich, harmonic overdrive. In “Clean” the amp responded more traditionally, staying clean and crisp longer with the midrange slightly pulled back yet still thick with overtones.

The front end also played well with an Ibanez TS9; the tone remained lively with plenty of that punchy midrange, but with more drive and sustain. The Tone control made quick work of switching from bright single-coils to darker humbuckers.

With the airy openness of the G12 Blue, the amp’s five watts still have plenty of horsepower, but are manageable for studio and rehearsal work. The reverb lives up to its “Space” moniker, with a long decay and slightly lo-fi tone that can be dialed in from a light sprinkle to a total drench.

With its cool space-age vibe, the Swart Atomic Jr. piggyback is a versatile high-quality amp with killer overtones and big spacious reverb.

This article originally appeared in VG September 2017 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.