[Boatanchors] Re: A moment, a day, a passing of a generation/a large question

[Mark Richards]

I had the benefit of an old-time Elmer sort who befriended many of us 
from the local high school Amateur Radio Club and who held theory chats 
and hovered over us while we nicked fingers on fresh aluminum stock; 
learned how to use a bending brake; and discovered that it's best to 
bleed off the B+ before grabbing that plate cap.

Experimenting to see what happens is always fun.  In the case you 
mentioned I am certain there's plenty of practical advice.  Approaching 
this as an engineering problem to solve "what if" it would be 
interesting to take a distortion measurement at full throttle, and then 
continue this as the B+ is lowered in steps, keeping watch on the screen 
current and other parameters, to see what happens.

If something melts, try again.

 > Is it just slogging through, blowing stuff up, and
 > conversing with virtual elmers?

I think it surely is!

If you don't have the benefit of guided hands-on, this group and a few 
others are great places to receive some guidance and mentoring, if you 
don't mind slogging through the occasional politic, that is.

/m


jeff wrote:
> On Thu, 2006-12-07 at 10:08 -0500, Mark Richards wrote:
>> Yes, we all know pearl harbor happened and how stellar our glorious 
>> leader is present day.  
> 
> Not to mention that both Pearl Harbor and 9/11 were allowed to happen,
> at very least, by powerful men with an agenda.
> 
> 
> But I agree with you on keeping on-topic.  To that effect, I have a
> question:
> 
> Short of figuring out that old time machine quandary, how does one learn
> hollow-state practical tips?  Yes, I've read a few books, taken a few
> things apart, attempted to build other things... but how does one learn
> without a nun over your shoulder, slapping your knuckles with a ruler?
> 
> How does one learn to look at a circuit and make changes to alter the
> output?  In a tiny class-A 6BQ5 audio amplifier circuit, if I lower the
> B+, will I lower output while retaining most of the fidelity?  I know I
> can use a resistor to lower the B+ - where do I start?  How much can I
> lower the B+?  Or should I keep the B+ as-is for the other tubes and
> just lower it for the output?  A 10w resistor in the power supply gets
> hotter than anything I've felt in a radio, yet calculations show it only
> dissipating 2w - why is that?
> 
> Where does one learn this stuff?  The practical info doesn't seem to
> appear in the books.  Is it just slogging through, blowing stuff up, and
> conversing with virtual elmers?
> 
> 
> 
>