Tube amp schematics 101, etc: NEW NEWER UPDATE: Biasing tutorial!

[Maggieo]

So THAT's what a "soul" control is!

Who does that? Carr?

[Jay]

Allen does the "Raw" control but IIRC from reading elsewhere on the interwebz, it actually bypasses the entire tone-stack to increase overall gain (pretty dramatically) as opposed to affecting negative feedback in any way.  Pretty cool trick that works great in pedals too, especially the big muff. 

[Fiddy]

I haven't been here too long but I think  it's pretty cool what you do Brad.

Im sure there's lots of us that truly appreciate it! 

Cheers!

[1946dodge]

Remember that this stuff is all according to my understanding, and I'm totally self-taught... no electrical engineer here, just a dorky amp guy... so I'm not responsible if there are gaps and possibly small accuracy quibbles.  I do try to only post stuff I know for sure, though.  Wink

Well I gotta tell ya, I am an electrical engineer and I am learning stuff from you (mostly long forgotten or never understood). You have just succeeded in waking up in me what I learned in the 60's when I went to school!
For that I thank you, my talented smart friend.

I am looking forward for anything you give us. It is the most lucid explanation I have seen in 40 years.

Thanks a million.

[1946dodge]

Me too. I read all the time. I am thankful that you read books, simplify what you read and give it to the rest of us.
That is science and engineering at its best.

[Superfuzz]

This thread must go into the library section..never learned so much in a sunday morining..

[1946dodge]

I think putting it in the Library is a great idea. Then it won't be hard to find.
However, I see that ####### has already put it as a pretopic so it will stay in one place too.

[noirengineer]

your the man! 

[Maggieo]

Hey Brad, can you explain what's up with "matched pair" power tubes?  In, for example, a 6V6GT powered amp, do both power tubes have to be the same brand or what?  I was thinking about dropping some of the spare 6V6GTs I've got for my Vibro Champ into the AST, but I only have single examples of any given brand of tube.

[Maggieo]

Yep, the Swart is cathode-biased.

So, different 6V6GTs will draw different amounts of current?  Why is that?

[Maggieo]

Wow!

I guess I'd better go looking for some NOS matched pairs to play with the Swart.

The Vibro Champ is cathode biased, too, right?

[Maggieo]

Thanks for the "used, test strong" tip, Brad!!!

I'll keep my eyes peeled.

[Regan]

Brad, all I can say is, "WOW"!!!!! Oh, yeah, and,  "THANKS"! I would say more but my brain is about to explode from all this information!!!


You 'da man!!!!!


Regan

[luau]

Here's the good news:  You can go to this page: http://www.webervst.com/tubes/calcbias.htm

Broken link. http://www.webervst.com/tubes1/calcbias.htm

[Fiddy]

I just spent like 3 hours re-reading this post.

Would anybody have some clear nice shots of the guts of a champ? Also a pic of a power transformer without the cap would be nice if anyone's got one?