Where can I find replacement tubes for my effect pedal, effects unit or distortion pedal?

For tube pedals, tube distortion units and rack effects units, suitable and cleanly selected preamp tubes are especially important. This applies, for example, to classics such as the B.K. Butler Tube Driver, the Mesa/Boogie V-Twin, the Blackstar HT-Dual or units such as the Damage Control Demonizer. The most requested types here are mainly 12AX7 / ECC83, and depending on the desired tuning also 12AT7 / ECC81 or 12AU7 / ECC82. Especially with such devices, not just any standard tube should be used, but a technically clean and tonally suitable selection. The S4GB tubes with different gain options are particularly suitable for this.