My Tube Collection, Welcome to share yours
- Thread starter adrian cheng
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Does your system need divine inspiration? These heavenly PCC88 may be the answer.
Sorry, my mistake, they were Mullard not Chinese . Not as good as the earlier Mullard
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I think these may be Irish since they are Dairy O'Miniwatt ..... 
1958 Philips Heerlen Miniwatt D getter E88CC
1958 Philips Heerlen Miniwatt D getter E88CC
Lovely logosI think these may be Irish since they are Dairy O'Miniwatt .....
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1958 Philips Heerlen Miniwatt D getter E88CC
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View attachment 157202
A lot of the tubes I purchased were tested, screened, and graded for noise and microphony by the seller. I can tell since the vendors had stickers on the tubes or the boxes; some used a small dab of paint on the tube.
This set of 6SN7/VT-231 had no markings, so they probably were not tested when I bought them.
I put them on the Maxi Preamp and was amazed at the results. They all test between 5% and 10% over nominal gain, they were all matched within 5% between triodes in any given tube. Also, they measured at less than -85 dB for noise.
In other words, they were all matched. I suspect that this was a result of them being from the same or subsequent months of production. And, they were likely tested/screened by Sylvania for the military.
This set of 6SN7/VT-231 had no markings, so they probably were not tested when I bought them.
I put them on the Maxi Preamp and was amazed at the results. They all test between 5% and 10% over nominal gain, they were all matched within 5% between triodes in any given tube. Also, they measured at less than -85 dB for noise.
In other words, they were all matched. I suspect that this was a result of them being from the same or subsequent months of production. And, they were likely tested/screened by Sylvania for the military.
Tested a lot of 12AX7/ECC83 on a Maxipreamp II and the best I've seen is -89.5 on a Siemens E83CC. The variation in noise is all over the place even in new tubes among different brands.
Only tested about 100 12AU7/ECC82 but they always seem to measure -83 to -86 for new or used tubes in great condition.
Just got into 12AT7/ECC81 so I have very few but I'm getting a few more good ones soon. The Philips JAN, RFT, Russian, both Siemens and the Valvo were purchased as new. The others were purchased as used. Gain, transconductance and noise 2 values each.
French1 41.0, 49.1 1760, 1790 78, 81
French2 48,2, 38.2 1980, 1670 76, 75
Philips JAN 52.1, 50.9 2100, 2090 73, 73
Mullard 51.2, 51.0 2130, 2160 73, 73
Mullard TK1 44.0, 46.0 1800, 1960 74, 74
Mullard 10M 48.8, 51.3 1900, 1890 85, 83
RCA 50.4, 47.4 2050, 2050 73, 73
RFT 46.2, 47.1 1950, 2040 75, 74
Russia 49.1, 44.8 2250, 2070 73, 74
Siemens E81CC1 45.3, 44.1 2030, 1930 85, 85
Siemens E81CC2 45.9, 43.7 2030, 2050 85, 85
Valvo 6201 40.6, 43.8 2090, 2130 81, 84
Gott
Gotta love the MaxiPreAmp II tester! It makes tube tests so convenient. Just wish that it had four octal sockets too and covered a wider range of 8 and 9 pin tubes.
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