Tweed ODS 5879 Load Line

[stevefmt]

I worked up the transfer curves for a 5879 in my tube analyzer, at a screen voltage of 45v.

When I plot the load line as per the voltages given in the Tweed ODS schematic, I get a very steep load line.  It looks like a gain of about 50.

Blencowe uses an example EF86 setup by having the load line intersect the knee of the transfer curve, and explaining why you might intersect a little above or below the knee.  So I guess those of you (tubenit?  geezer? etc) who worked on the Tweed ODS can help me understand the idea of setting up the load line WAY above the knee (presuming I derived it corrrectly).  Is this to obtain some particular distortion character?

Thanks, Steve

[tubenit]

Simple answer for myself is that I experimented alot & put many many hrs into all of that and when I found something that I liked tonewise, I simply stuck with it. It should be noted the majority of my experimenting resulted in poor results or sometimes sheer failure.

I never paid any attention to load lines. Often I would see some component value or design in some one's schematic  and simply try it out and modify it if it wasn't what I wanted. I have zero formal training in electronics so my approach has typically been trial and error.


Looking back on those days, I can remember posting schematics with a one tube reverb and then people telling me what I was doing simply wouldn't work. Yet, I was getting all the reverb I wanted and still was having people inform me that what I was doing simply wouldn't work at all. (Ironically, the one tube reverb idea wasn't mine to begin with.)  Kinda funny looking back on it.   

I've always viewed the Tweed ODS, the D'Mars, HoSo56, Carolina Blues Special, Carolina Overdrive Special and other amp ideas to be amps that one would build and then tweak to their personal values tonewise.


Respectfully,  Tubenit