Mullard CV4004/12AX7 boxed-plate, made in Great Britain. The box plates are immediately discernible from other 12AX7 variants. This makes for a more bold and upfront soundstage while retaining that famous Mullard smoothness. Made in Great Britain for the English Military, the CV4004 is one of the best 12AX7 variants you can use for any type of audio.

Tested NOS with Amplitrex tube tester.

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