Simplified F5 as Headphone Amplifier. Easy project.

This idea is based on the F5 Simplified schematic by Nelson Pass.
As it stands it is for 32 Ohm headphones.
The gain is a bit over 2.
Gain can be adjusted by R2 and R7 for other headphones.

Transformer can be 2x12VAC or possibly 2x15VAC.
The bias is here 227mA Class A and this gives a THD like 0.010%.
 

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DC offset behavior is important thing, when dealing with cans

that needs to be confirmed in vivo, not just sim

thermal stability depends largely on heatsinking arrangement - it can be a problem without source resistors if not using substantial heatsinking for task
 
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Yes, DC-Servo is an option.
Rod 'ESP' Elliott has an artcle on both non-inverted and inverted DC-Servo.
https://sound-au.com/articles/dc-servo.htm

To play it simple and safe we can always add an output capacitor.

If we look at my circuit I do not think it will be a issue with DC-offset.
Once we adjust for lowest DC-offset it would stay low.
And then we can add headphones with no problem.
The question is how fast would it settle after powering on? Even with a large current it will need some time to reach the thermal balance. Another issue might be the turn on thump, which might be dangerous to headphones. We can go with KISS and introduce a delay, but I'm not sure that's going to be enough.
 
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