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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
tavishdad

Showing 1 response by elevick

elevick
2,638 posts
 
Nice start. This is going to get really deep. I think that you need a lot more samples to accurately test a manufacturer. My guess is that a minimum of 30 tubes to get an accurate sample. Different run dates and factories make a huge difference on some. I know that some companies like Shuguang actually pick the best out at times and sell them as superior tubes.

Also, did you buy matched pairs/quads? That would mean the dealer already took out the garbage.

Finally, instead of giving the high and the low let's get down to real sampling: Use Standard Deviations. It's a much better number to judge by. Then if you get into variances you can compare different kinds of tubes not just different manufacturers...It will let us know things like the best overall consistency from a single manufacturer regardless of tube type.
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