NOS Mullard ECC83/12AX7 CV4004 1960s
Marked and boxed as CV4004 Made in Great Britain with Mullard Blackburn production codes. Regular, "ladder" type getter as opposed to the often seen "box plate" CV4004 tube.
Photo shows the plate style but is not a photo of the tube for sale.
Mike: I ordered more of these because these are the best Mullard 12AX7-style tubes I think I’ve ever heard. In lay terms, they are completely devoid of noise and microphony. Clearly a stout, truly NOS tube that does the term “NOS” proud and that will be at home in many different kinds of amplifiers. Wow! Cheers, Mike