Home Tubes Asylum

Questions about tubes and gear that glows. FAQ

RE: 12AU7 Reviled

"bad stuff"

I'm not certain what you mean by "bad stuff" but different tube types have inherent characteristics such as their operating points and distortion profiles. It is simply a function of their technical design. Some tubes have lower distortion than others as a result.

It turns out, based upon distortion tests done by respected engineers over many decades, that the distortion characteristics of a 12AU7 are inferior to many other triodes that are similar in operating conditions. For instance the 37, 76, 6P5G, 2C22, 7119, 5687, 6CG7, 6F8G, and the venerable 6SN7 all have lower second and third harmonic distortion when compared to a 12AU7. For more information you can read Morgan Jones, 'Valve Amplifiers' for the most comprehensive evaluation and "Distortion In Audio Phase Inverter And Driver Systems," W. B. Bernard, IRE National Convention Record, 1958, Part 7, E 87. For a less comprehensive review see the VTV article below.

It seems clear that contemporary consumer gear uses the 12AU7 simply because it is readily available as a result of the guitar amp market where distortion is of no concern.



Edits: 07/02/21 07/02/21

This post is made possible by the generous support of people like you and our sponsors:
  Atma-Sphere Music Systems, Inc.  


Follow Ups Full Thread
Follow Ups

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.