I don't get this. Noise from tubes is in my experience a variable related to sampling, and of course high gain tubes will tend to have more noise those that afford less gain, when used in a gain stage. Then too, the circuit design is critical and so are the voltage and current chosen to run the tube. These elements and more constitute a calculation of noise that has so many variables as to make the outcome unpredictable in advance. IMO, you have to measure noise in-circuit and experiment to determine whether substitution of one 12AX7 (for random example) with another 12AX7 results in audible or measurable improvement.
List of Audio Tube Measured Noise Performance
I have begun to post and maintain a list of the measured noise performance of the types of vacuum tubes typically used in phono stages and other low-noise audio equipment. It might be of interest to any audiophile replacing or upgrading tubes in a phono stage.
So far the list is modest, with samples of twelve different brands and/or types, and a total of 58 tubes measured, but it is updated regularly. It includes tubes such as the 12AX7, 12AT7, 5751, 6922 / 6DJ8 / E88CC, and 6SL7GT. And it includes a sampling of tubes from all three major current production tube factories, as well as some new, old-stock (NOS) tubes.
I don’t sell tubes (or own stock in any tube factories), and the list is strictly measurement-based, so I believe it is completely objective. And I explain in detail how the measurements are made, for anyone who would like to repeat them.
You can see the list at:
http://tavishdesign.com/pages/downloads
I’d be interested in hearing about other tubes or brands you think should be included.
Scott
So far the list is modest, with samples of twelve different brands and/or types, and a total of 58 tubes measured, but it is updated regularly. It includes tubes such as the 12AX7, 12AT7, 5751, 6922 / 6DJ8 / E88CC, and 6SL7GT. And it includes a sampling of tubes from all three major current production tube factories, as well as some new, old-stock (NOS) tubes.
I don’t sell tubes (or own stock in any tube factories), and the list is strictly measurement-based, so I believe it is completely objective. And I explain in detail how the measurements are made, for anyone who would like to repeat them.
You can see the list at:
http://tavishdesign.com/pages/downloads
I’d be interested in hearing about other tubes or brands you think should be included.
Scott
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- 20 posts total
- 20 posts total