1960's RCA Marked Heintz and Kaufman 6SL7GT ECC35 Tubes - Matched Pair, NOS/NIB, Tested, Matched Codes

1960's RCA Marked Heintz and Kaufman 6SL7GT ECC35 Tubes - Matched Pair, NOS/NIB, Tested, Matched Codes

These tubes were made by RCA and have black plates, D getters and matched 1960's date codes. Heintz and Kaufman was a tube manufacturer from the 1930's to early 1950's and eventually became a rebrander of tubes.

These were tested on my calibrated TV-7/U. They have been tested for shorts, gas, and transconductance. All of the tubes test with readings of 56/58 and 55/58. Minimum is 32.

They have been sonically tested in my DIY pre-amp and are quiet with no noise or microphonics.

I will combine shipping. Just ask.

I will ship international.

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