Tung Sol Reissue - test results
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This is a post I answered on another forum that I thought may be of interest to some of you:
Myles,
Thanks for the advice, on the 12AT7's. I am still trying out different tubes and the Tung Sol 12AX7 may be all the Agression I need.
Brendan
Brendan,
The current batch of Tung Sol reissues are great tubes and some of the most consistently high in gain of today's production tubes. The rightmost column is true, actual gain. Most of today's tubes are 75-85, most around 80 actually, so these are a great batch. Having a tube 5 points in gain lower than another in V1 will make a difference most folks can hear easily. Having a tube with plate current output down 20% from spec (spec is 1.2mA) as a phase inverter will also impact things a lot in most amps:
Design spec is:
1600 TC
1.2mA plate current
100 gain
Plate
Current TC Gain
1.0 1470 0.0155 94.8
1.4 1840 0.018 102.2
1.1 1320 0.015 88.0
1.1 1510 0.016 94.4
1.1 1560 0.018 86.7
0.9 1490 0.016 93.1
0.8 1340 0.015 89.3
1.0 1560 0.018 86.7
1.1 1630 0.0175 93.1
1.3 1740 0.0185 94.1
1.2 1650 0.018 91.7
1.0 1540 0.017 90.6
1.0 1400 0.015 93.3
1.2 1670 0.018 92.8
1.4 1730 0.018 96.1
1.5 1910 0.019 100.5
In another batch the final specs were:
Averages:
Plate Current Output 1.1 mA
Mutual Conductance 1514
Gain 88
High TC 1610 100.6%
Low TC 1320 82.5%
QA tolerance TC 18.1%
High mA % 1.3 108.3%
Low mA % 0.8 66.7%
QA tolerance mA 41.7%
High gain 91.2 91.2%
Low gain 84.7 84.7%
QA tolerance gain 6.5%
--------------------------------------------------------------------------------
This is a post I answered on another forum that I thought may be of interest to some of you:
Myles,
Thanks for the advice, on the 12AT7's. I am still trying out different tubes and the Tung Sol 12AX7 may be all the Agression I need.
Brendan
Brendan,
The current batch of Tung Sol reissues are great tubes and some of the most consistently high in gain of today's production tubes. The rightmost column is true, actual gain. Most of today's tubes are 75-85, most around 80 actually, so these are a great batch. Having a tube 5 points in gain lower than another in V1 will make a difference most folks can hear easily. Having a tube with plate current output down 20% from spec (spec is 1.2mA) as a phase inverter will also impact things a lot in most amps:
Design spec is:
1600 TC
1.2mA plate current
100 gain
Plate
Current TC Gain
1.0 1470 0.0155 94.8
1.4 1840 0.018 102.2
1.1 1320 0.015 88.0
1.1 1510 0.016 94.4
1.1 1560 0.018 86.7
0.9 1490 0.016 93.1
0.8 1340 0.015 89.3
1.0 1560 0.018 86.7
1.1 1630 0.0175 93.1
1.3 1740 0.0185 94.1
1.2 1650 0.018 91.7
1.0 1540 0.017 90.6
1.0 1400 0.015 93.3
1.2 1670 0.018 92.8
1.4 1730 0.018 96.1
1.5 1910 0.019 100.5
In another batch the final specs were:
Averages:
Plate Current Output 1.1 mA
Mutual Conductance 1514
Gain 88
High TC 1610 100.6%
Low TC 1320 82.5%
QA tolerance TC 18.1%
High mA % 1.3 108.3%
Low mA % 0.8 66.7%
QA tolerance mA 41.7%
High gain 91.2 91.2%
Low gain 84.7 84.7%
QA tolerance gain 6.5%
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