Basic headphone amp

[ruffrecords]

That circuit has problems. It has no current limiting resistors, no drain resistors, the feedback network resistors are unnecessarily large, that chip cannot drive heavy loads to a high level well (which ironically is exactly what the text claims the circuit provides) and it's a little fast for single supply with one film bypass cap.

I think you have to remember it is a hi-fi design. They seem to be obsessed with 100K input impedances. It also has a 100uF electrolytic across the supply as well as the film cap so perhaps not that fast after all. But the lack of current limit and drain resistors is a definite amateur mistake.

Cheers

Ian

 

[Bo Deadly]

I think you have to remember it is a hi-fi design.

I have not tried loading an OPA2134 with 30 ohms (and probably never will because I get a twitch in my eye when asked to pay for things that are unnecessarily expensive) but I doubt very much that the fidelity would be very high. With +-6V there might be some highish build-out resistors that would keep the amp THD down and still put out enough power but as-is it doesn't have any so ... fail.