Here we have for sale is a very rare 12AX7 ECC83 tube. This is a special quality ANOS tested Mullard B339 ECC83 tube based off the M8137 CV4004 box plate design. Platinum BALANCED triodes. My personal favorite 12AX7 variant as the Mullard M8137 CV4004 has the best bass qualities of any 12ax7 ecc83 tube in my personal opinion.
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