a simple (I think) Baxandall question

[mashaffer]

Since the Baxandall tone control is a nfb based circuit is the linearity of the underlying device improved through the entire frequency range?

 

[ruffrecords]

Yes and no. The amount of NFB varies with the setting of the control so the improvement in linearity varies the same. More boost means less NFB and less linearity improvement and vice versa.

Cheers

Ian

 

[Merlinb]

Exactly what Ian said. Here's an example from my book, using a 12AT7. At the flat setting the distortion is a factor of ten lower than the open-loop performance.

An externally hosted image should be here but it was not working when we last tested it.

 

[kevinkr]

Merlin, I just got your book. Highly recommended.

Using a higher mu triode allowing for more feedback margin under boost conditions should help overall distortion, but the relationship of distortion to boost Ian and Merlin mention still applies. Using a more linear device to start with helps too.

 

[mashaffer]

Thanks much guys. Just the info I needed.