1) A rare pair of Raytheon CK 7729 gold pin vacuum tubes. These tubes are a low noise, low microphonics industrial version produced for critical applications such as aviation. These very rarely come up for sale. These tubes were made by Raytheon as designated by the "280" EIA code. They also have the same date code of "63-17" which corresponds to the 17th week of 1963. These tubes have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 99% Triode 2: 99%
Tube 2: Triode 1: 99% Triode 2: 99%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.
I would like $175 plus shipping for these tubes.
2) A trio of 6679 12AT7 tubes manufactured by RCA. The 6679 tube was originally manufactured for mobile communication and maintain output even with variations of filament voltage. They are equivalent to a 12AT7 tubes. These tubes have square getters and all three have the date code of "6122" which equates to the 22nd week of 1961. These tubes have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 102% Triode 2: 103%
Tube 2: Triode 1: 102% Triode 2: 102%
Tube 3: Triode 1: 102% Triode 2: 102%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of all three tubes performed excellently.
I would like $40 plus shipping for these tubes.
3) A pair of General Electric 12AY7 tubes. These tubes have angled square getters and grey plates. They have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 95% Triode 2: 94%
Tube 2: Triode 1: 95% Triode 2: 95%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.
I would like $35 plus shipping for these tubes.
4) A Mullard ECC81 12AT7 vacuum tube. This tube has a square getter and has the code sequence Tk1 B8F with the "B" signifying the Blackburn, England Mullard plant where this tube was produced. This tube has been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 100% Triode 2: 99%
In addition this tube has had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of the tube performed excellently.
I would like $20 plus shipping for this tube.
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 99% Triode 2: 99%
Tube 2: Triode 1: 99% Triode 2: 99%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.
I would like $175 plus shipping for these tubes.
2) A trio of 6679 12AT7 tubes manufactured by RCA. The 6679 tube was originally manufactured for mobile communication and maintain output even with variations of filament voltage. They are equivalent to a 12AT7 tubes. These tubes have square getters and all three have the date code of "6122" which equates to the 22nd week of 1961. These tubes have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 102% Triode 2: 103%
Tube 2: Triode 1: 102% Triode 2: 102%
Tube 3: Triode 1: 102% Triode 2: 102%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of all three tubes performed excellently.
I would like $40 plus shipping for these tubes.
3) A pair of General Electric 12AY7 tubes. These tubes have angled square getters and grey plates. They have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 95% Triode 2: 94%
Tube 2: Triode 1: 95% Triode 2: 95%
In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.
I would like $35 plus shipping for these tubes.
4) A Mullard ECC81 12AT7 vacuum tube. This tube has a square getter and has the code sequence Tk1 B8F with the "B" signifying the Blackburn, England Mullard plant where this tube was produced. This tube has been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:
Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 100% Triode 2: 99%
In addition this tube has had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of the tube performed excellently.
I would like $20 plus shipping for this tube.
Attachments
Last edited: