RCA, NIB Made By GE 6681 / 12AX7A Gray Plate Perfectly Balanced Single NOS ECC83 12AX7

This is an incredibly rare, pristine vintage find for high-end audiophiles and serious collectors. A perfectly valanced single RCA/GE 6681 / 12AX7A tubes. It was manufactured in the USA by GE and is branded RCA. It was manufactured in 1978, week 26. The plates are well matched and balanced, and test stronger than NOS. This tube was manufactured to rigorous specifications for reduced noise and microphonics. This tube has gray plates, red lettering, and top halo getters. These are highly sought after RCA/GE 6681 / 12AX7A tubes, act quickly before they sell out!! More available upon request.

The 6681 premium advantage: The 6681 is not your standard 12AX7A. It is a ruggedized, industrial, and communications-grade masterpiece engineered with a heavy-duty filamentdesigned to withstand rapid on-off cycling. They offer an ultra low noise floor, exceptional microphonic resistance, and incredible longevity.

Factory date matched consistency: This tube shares almost identical vintage factory date/batch codes. This means it was manufactured using the exact same chemical metallurgy and cathode coatings on the same factory line. For high-fidelity stereo preamps (like McIntosh, Audio Research, or Conrad Johnson), this ensures perfect channel uniformity and pristine stereo imaging.

Attention musicians: if you are hunting for the ultimate V1 upgrade to elevate your vintage Fender Blackface, Tweed, or boutique amp, this ruggedized RCA-branded 6681 provides that legendary, smooth American midrange bite. This factory-balanced single gives you a studio-grade stash of premium tubes to completely retube your favorite heads or combos with an ultra-low noise floor, massive headroom, and zero hiss.

Be careful buying tubes from other sellers who list "matched pairs" but do not provide test results or specify the equipment that they use to test their tubes.

I personally tested this tube on my recently calibrated Hickok 600a and TV7D/U tube testers.

The results are as follows:

1,975/1,975