Triode Bias 101

[woodrough]

Hi! I am Kyle, and I am slowly amassing intel to construct an aikido phono circuit. I have a few principle questions on tube biasing. Although all the values are given to produce quality sound, I want to be able to backtrack the design and see where the 12ax7 tubes I select will sit on the charts. (sweet spots)

So the basics:
(1) on the chart how are the lines derived?
(2) what are the steps on selecting the proper values
(3) how to read the chart with my selected vales
(4) what are danger areas. (being that I want minimal distortion)

I have been trying to reed through Nazaroos bias chart, but there are some steps I have to understand before tackling this chart properly:

Golden Tubes: Tube Biasing 101 (Pt 2): 12AX7 bias chart!

I have been digging for the tutorials, so if anyone has a reference source for me to read through, that would be ultra!

 

[TonyTecson]

How to design valve guitar amplifiers

 

[woodrough]

ah! Excellent! I read through the 'Triode Gain Stage' chapter and got a pretty sweet overview on the biasing basics.

I also just landed on the page "The Shunt Regulated Push-Pull (SRPP)", looks just like the set up that the Aikdio shares. Currently this site is answering all my questions.
This whole site is the goldmine! Thank you Tony.

 

[boywonder]

education+diy

 

[TonyTecson]

patrick turner is a good teacher....

 

[woodrough]

ohyes! I was originally looking at the PhonoDude design alot as well. One of the reasons of truly getting to the bottom of all this was to understand the differences between the mu-follower vs srpp (Aikido)

Alot of confusion started to arise when dealing at super low pre amp levels (Strange Ra numbers). I felt obligated to go back and verify and reproduce these models via LTspice myself.

Thanks for the forwarding of links! These are extraordinarily helpful. Slow reading and weeding