[Amps] Amp 101

[Robert Tortajada]

Greeting everyone, I just got my first amp, a Heathkit sb-220.  Ok, I 
will admit that  I have never had an amp and it's been 20 years since I 
knew what a plate and grid was. Well, admitting you have a problem, in 
my case ignorance, is the fisrt step to a solution.

Can anyone recommend a good source of information on the basics of 
testing and eventually tuning/operating such a beast?

Thanks in advance
Bob - K2ZC