Home Digital Drive

Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

Sort of-ish

Triodes are square law devices, like FETS. This is not linear. You could operate them only over a narrow range of their characteristic where they will approximate a linear characteristic but that is the same with any non-linear device - if you operate it only over a tiny portion of its range it will approximate to linear (whether that range is large enough to do anything practical is TBD). Degeneration and global feedback work in the same way, so if you think global feedback is bad you should not look at degeneration as good (a difference is that degeneration applies to one device so stability is not an issue, but then global feedback stability around many stages is not an issue if it is done right).

The topic of feedback translating low order harmonics to high order harmonics is an interesting one. It was raised decades ago in Wireless world magazine with an example of a single stage amplifier that had a large amount of purely second harmonic. After applying feedback the second harmonic was reduced considerably but also low levels of higher harmonics appeared. The F-Word article that I linked to in a previous post covers this case in the Section 'Storyline 2: Re-entrant distortion'. At worst, this is a case of going from no high order harmonics to a small amount of high order harmonics but never 'high order dominant'. And, there are no truly square-law devices, they all have some imperfections that make them not pure square law so they create high order harmonics on their own - I have never seen a single-ended triode power amp spectrum that did not already contain a spray of 3rd, 4th, 5th etc harmonics.



Edits: 02/16/24 02/16/24

This post is made possible by the generous support of people like you and our sponsors:
  Schiit Audio  


Follow Ups Full Thread
Follow Ups
  • Sort of-ish - 13th Duke of Wymbourne 14:52:23 02/16/24 (2)

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.