help in this scheme

I decided to finally build a valve tube amplifier
walk exploring the theme of building a vacuum tube amplifier i find this scheme which I think was
a good way to start but a i have same questions
the scheme



this are my questions
then what I wanted to discuss was the following
consider a good project for first job
they think the performance that he will
the power supply can feed another channel without loss of quality
had been worthwhile to replace the diodes for rectification by a valve grinder and if so how the scheme had been
What does the feedback loop


sorry about my inglish i am from portugal

please help me

 

I used to run stump grinder-you can never have too much power!

 

Looks like a nice simple circuit for a project.

Cannot quite make out your question regarding the feedback loop, but with feedback applied you will get lower distortion, lower output impedance and lower overall gain.

Removing it completely will be interesting as while distortion will increase it might not sound unpleasant - probably quite nice in a euphonic way. The increase output impedance would be of concern unless you are running high impedance drivers, preferably without electronic crossovers such as Lowthers which will give you a pretty flat impedance curve and have good inherent mechanical damping.

One benefit of replacing the SS diodes with valve rectifiers is soft start-up.