Thomas Mayer continues the Loktal theme with the 7A4 as the tube of the month. Being electrically equivalent to the 6SF5, the 7B4 can be implemented as the very first valve in the Octal Phono Preamplifier. The 7A4 is the Loktal equivalent of the 6J5 and with the 7B4 and 7A4 combination, they can form a great combo for the Loktal Phono preamplifier.

The 7A4 have the same pinout as the 7B4, but here the similarity ends. The 7A4 has a much lower mu of 20 combined with a plate resistance around 7kOhm. Like the 6J5 it is basically one system of the 6SN7 or 7N7 which is the 6SN7's Loktal equivalent.

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