Tube SQ will vary with different circuit designs.
No graphic illustrations, but the following is informative.
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At Upscale Audio, Kevin Deal describes the SQ of various tubes - such as this video.
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Re: Tube Manufacturers. Many branded tubes were actually subcontracted out to competitors who had the requisite machinery for a particular tube type - but labeled accordingly. When electronics started switching over to transistors, many tube companies went out of business - but their brand names and IP were purchased by competitors and kept in the marketplace for a long time. For NOS tubes, only knowledgeable tube dealers can determine what tube was made where, when and by whom.