Need some loadline help

[jwags81818]

I am trying to learn how to draw loadlines. Can someone please look at the attached schematic and give me operating points for the D3a and the 3ooB? When I do it I am coming up way outside normal operating parameters and I have been using the amp for 5 years and it sounds great. Also I may have a few questions when you are done if you dont mind.

Thank you

Jeff

 

[Fuling]

 

[jwags81818]

Thank you very much! Do you think the 300B operating point could be improved upon? It seems it the voltage was lowered some and the line was tilted to a little more of an angle it would be more linear. But could it be done without exceeding the 60ma limit of the output traffo??

 

[kmtang]

https://trioda.com/tools/triode.html

You may try using this online Triode loadline calculator program which is a bit easy to work on.

Johnny

 

[Merlinb]

Thank you very much! Do you think the 300B operating point could be improved upon? It seems it the voltage was lowered some and the line was tilted to a little more of an angle it would be more linear.

You can trade linearity for output power. Pick one. (More horizontal load line = lower distortion but less power)

 

[Tjj226]

Thank you very much! Do you think the 300B operating point could be improved upon? It seems it the voltage was lowered some and the line was tilted to a little more of an angle it would be more linear. But could it be done without exceeding the 60ma limit of the output traffo??

If you don't feel comfortable using the calculator, the western electric data sheet for the 300b actually gives you a list of operating points and their measured distortion.

http://www.tubebooks.org/tubedata/we300a_b.pdf

The datasheet suggests using some more unconventional operating points will yield better performance.

 

[Fuling]

AFAIK, 5,6k is an unusually high Z plate load for a 300B. 2,5-3,5k seems more common, but I bet 5,6k can sound very good if you don't need the extra watt or two that you can get from a low Z load.