Hi. I am designing an hifi amplifier a simple stereo 1 gainstage and 1 phase inverter, and a push pull kt66 based on the leak 60 strereo.
I wanted to know because I am designing everything from scratch. How could i determine the value of the plate resistor. By looking at the tubes datasheet, i understand it is kind of arbitrary and should be decided depending on the distortion thd and to the amount of voltage we want to swing.
But in practice how do i design for the lowest amount of noise and lowest thd, is it even possible ? As using a bigger plate resistor equals more noise, but less distortion ? conflicting.
Thank you.
I wanted to know because I am designing everything from scratch. How could i determine the value of the plate resistor. By looking at the tubes datasheet, i understand it is kind of arbitrary and should be decided depending on the distortion thd and to the amount of voltage we want to swing.
But in practice how do i design for the lowest amount of noise and lowest thd, is it even possible ? As using a bigger plate resistor equals more noise, but less distortion ? conflicting.
Thank you.
Also you may need a large plate voltage swing, depending on the phase inverter type chosen.
Work backward from the output stage. All design is compromise.
https://pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_51/4410_Preview_Contents.pdf
Work backward from the output stage. All design is compromise.
https://pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_51/4410_Preview_Contents.pdf
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Thank you rayma i will bookmark this link. Tomorrow i will try to design from the power section, because i never tried this. Also i choose the long tail phase inverter, i think its the best phase inverter (not the best balance, but it can do everything else).
You are biting off a relatively complex first build. IMO, you should consider simplifying it where possible.
A good source for easy to understand and educational stage design information is How to design valve guitar amplifiers. It addresses both of your questions so far (power supply decoupling and triode voltage amplification design) and probably a number of your upcoming questions. The author is a member here as well and very helpful.
A good source for easy to understand and educational stage design information is How to design valve guitar amplifiers. It addresses both of your questions so far (power supply decoupling and triode voltage amplification design) and probably a number of your upcoming questions. The author is a member here as well and very helpful.
This will be good for educational purposes. He can decide later if it will be is too difficult to actually build.
Be aware that guitar amplifiers are rather different in approach from hi-fi amplifiers.
Be aware that guitar amplifiers are rather different in approach from hi-fi amplifiers.
I wanted to try first a guitar amplifier, but after reading some post, i understood it is a random process and most are just trying values until it sounds good. And also i dont have a guitar😉
So I decided to go more scientific and choose a stereo amp because i will actually use it, and learn the real design of tube amps. With real concepts of thd, and a more scientific approach.
I already build microphone preamps, so i am safe, but this kind of hifi amps, bring new level of dedication. I could just go copy but I would not learn anything, so I start from scratch and look at other designs.
Thank you for the help.
So I decided to go more scientific and choose a stereo amp because i will actually use it, and learn the real design of tube amps. With real concepts of thd, and a more scientific approach.
I already build microphone preamps, so i am safe, but this kind of hifi amps, bring new level of dedication. I could just go copy but I would not learn anything, so I start from scratch and look at other designs.
Thank you for the help.
Can I just say simulation is a good way forward - there are pitfalls but if it does not work in simulation it does not usually work. Something like LTspice - there are tube models on diyaudio so you can play with the input stage phase splitter etc.
If you read the Radiotron ( you can find it in the web) probably you can understand a lot of things before to start with a project.
Your question are very basic so a good reading will help you.
Walter
Your question are very basic so a good reading will help you.
Walter
Thank you. Sorry to bother you guys I will read and simulate, a lot this week, and when I come back it will be with more advanded questions hopefully. Thank you all.