You are bidding on a matched pair of GE mil-spec 6072 12AY7 5 Star audio tubes.

These tubes were made for IBM for use in their computers. 1950's computers used vacuum tubes and required 10,000 hour tubes. These are GE 5 Star tubes custom marked for IBM.

These tubes have triple mica construction construction with skinny ribbed black plates, and tilted "D" getters. They have matching date codes are from the early 1950's.

These were tested on my Dan Nelson calibrated TV-7B. They have been tested for shorts, gas, and transconductance. The tubes test very strong with readings of 60/62 and 64/66. Minimum is 32.

They have also been checked for noise and microphonics in the phono stage of my Fisher 800B and are dead quiet.

All tubes are tested on my calibrated TV-7/B or on my calibrated Hickok 539C. All of these tubes have been tested for transconductance, shorts, gas, leakage and life. All tubes meet or exceed manufacturer published specifications of transconductance (Gm) for the specified tube type. All tests are tested twice - prior to the listing and prior to shipping.

I have been selling tubes on the internet since 1998 and have been working with tubes since the early 1960's.

If you have not already done so, please take a moment and look at my feedback.

All tubes are 100% guaranteed good on arrival.

These are great tubes for your new audio gear, guitar amps and vintage stereo/audio gear.

Thanks for viewing my auction. Please check out my other auctions for more audio tubes, ham radio and radio related items, and collectibles for great deals.

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Regarding Shipping

Your tubes will be well packed. All tubes are shipped in white boxes or the original boxes if available. They are than are wrapped in bubble wrap and shipped in a box. I have shipped thousands of tubes all over the world and have not yet had any arrive damaged.

Payment must be received with 2 days of the auction close. Foreign bidders are welcome to bid.

I will gladly combine auctions to save on shipping when possible.

I have sold and shipped electronic equipment and tubes to over 70 countries.

I pack items very well.

See my feedback and buy with confidence!