Which tubes are suitable for LEAK as replacements or as a sonic upgrade?

With LEAK, a targeted tube selection is often more worthwhile than a simple replacement. This applies especially to classics such as Stereo 20, TL/12 Plus, TL/12.1 Point One or the Varislope preamplifiers. In the Stereo 20, EL84 and ECC83 are particularly interesting; in the TL/12 Plus, rather EL84 with EF86 and ECC81; and in the TL/12.1 Point One, the KT66 plays a central role. These well-known LEAK units in particular often respond very well to a carefully selected tube configuration.