Which ECC83 or 12AX7 tubes sound warm, pleasant and unobtrusive?

Among newly produced tubes, these are:

ECC83 S4A Smooth – pleasant, smoother and unobtrusive tube sound with good resolution

12AX7 Tung-Sol – subtle, warm, good for voices and smaller ensembles

5751 Tung-Sol – usually interchangeable; the slightly lower gain can be useful, good for full-range drivers and horns

ECC83S from JJ – very well suited for rock and pop, but also classical music – the price hit in this category

ECC83 Mullard / 12AX7 Mullard Reissue from Russia – sounds warm, but does not come close to the original

12AX7-S PSVANE – can also be tested in this context

When it comes to NOS tubes, it can become very expensive, or the type may already be sold out. It is advisable to always buy such NOS tubes from a specialist dealer, for example BTB.

ECC83 Valvo – the warm-sounding all-rounder; everything is simply right here

ECC83 Mullard NOS (not reissue) – warm, many details, but also slightly more open than Valvo

ECC83 Tungsram – rare, high quality and well suited for frequent listeners