Elektor's LM317 Class "A" amplifier

[jackinnj]

November December 2016 issue has a Class A amplifier predicated upon 4 LM317's with +/- 15V rails. When I simulate it using TINA (8R load) it seems to distort at less than 5W out instead of the 12-14W claimed in the article. There being no supporting data....

100k/100p Rf/Cc was changed to 100k/10p for the a.c. analysis as the turnover was too low:

 

[ammel68]

Voltage regulators used for amplification?
I just learned something new.

 

[wintermute]

Elvee has posted a number of LM317 amplifier circuits in the past. Here is one of them http://www.diyaudio.com/forums/chip-amps/192934-se-class-regulator-chip-amp-madness.html#post2648702

Tony.

 

[kct]

Neat idea.

 

[wintermute]

jackinnj, is your LM317 model ok? Take a look at the link I posted of Elvee's amp. edit: Most LM317 models can only provide 500mA current....

Tony.

 

[kct]

I would use a MIC29503WT instead of the LM317.

 

[Ian Finch]

MIC29503 is an LDO regulator. I understand they won't work or there may need to be some changes for them to work as a linear amplifier.

 

[davidsrsb]

This is the kind of "away from the datasheet" use of a chip that is going to be very make dependent

 

[jackinnj]

This is the kind of "away from the datasheet" use of a chip that is going to be very make dependent

The NatSemi datasheet has an amplifier ap for the 317