Used Koch Classictone SE guitar amp

The Koch Classictone SE series is a boutique, minimalist line of guitar combos built in the Netherlands.

The "SE" stands for Single-Ended, meaning the power section utilizes just a single power tube running in pure, unadulterated 100% Class-A topology. Koch’s engineering philosophy here is "less is more"—by stripping the signal path down to the absolute bare minimum of components, the amp responds with lightning-fast dynamics, extreme touch sensitivity, and raw, organic tube coloration.

The single coolest feature of the Classictone SE series is its built-in auto-bias circuit. Because it handles biasing automatically, you can pull the stock power tube out and drop a completely different type of tube in to instantly change the entire power-amp voicing and headroom structure—zero tech bench work or rebiasing required.