Looking to warm up your HK 20? This is our Standard Retube Kit for the Hughes & Kettner Tube 20, Studio 84 and Edition 20 Combo Amps. It uses two ECC83S's with one being current balanced for the phase inverter in V2. The default power tubes are a matched pair of the JJ EL84's. With the Customize option you can configure this kit to use the JJ EL844's which will drop the power output a couple decibels (ideal for players wanting decreased headroom/output).