Hello – I have a matched pair of RCA 5691 6SL7GT ECC35 Red Base Tubes for sale.
These are NOS and new in the box tubes.
The 5691 is a drop-in replacement for the 6SL7 series of tubes.
These tubes have triple mica construction, gray ladder plates, double square getters at the tops of the tubes and steel support rods to minimize microphonics. They have 1967 and 1968 date codes.
TV-7/B test results: 54/52 and 50/48. Minimum is 32.
They have also been checked for noise and microphonics in the phono stage of my DIY pre-amp 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.
Please e-mail me if you have any questions.
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I will ship international.
Free shipping in the USA.
Canadian shipping is $15.00 and international shipping by first class is $18.00.
Your tubes will be carefully packed.
No charge for paypal.
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