YAQIN MC-13S Amplifier Push-Pull Integrated Vacuum EL34 12AXT7×4 Tube Amplifier
Now Yaqin MC-13S tubes are all transparent EL34-B tubes. 220V/230V/240V Yaqin products, the back pressure converter switch label is only 230V. For 110V, the label is 115V. Arkin manager explained that they only have this switch type.