you would find just a big transformer and a handful of small electronic components inside a power brick

Billy Corgan (Smashing Pumpkins)

and this achieves that

Preamp: Nutube 6P1

Yamaha A1M - Vintage Natural Brand_Gretsch you would find just aA Series The Next Level Designed to be the ideal performance acoustic guitar, the Yamaha A Series is crafted from the ground up, perfectly suited for life on the road. With legendary, Yamaha road ready construction, the it's the perfect guitar to take your playing to the next level. The A1M features a solid Sitka spruce top with scalloped bracing, mahogany back and sides and the Yamaha original SRT piezo pickup for solid, plugged in performance.