Discrete 4x1.5V Battery Headphone Amp, Lowpower

[lineup]

It works down to +/-2.0V.
Distortion is low and current consumption is only like 3-4mA depending on the status of the batteries.
Has been tested in simulation with 32ohm and 300ohm load.

I challenge everybody to try to design a real lowpower headphone amp for +/-2.0V.
Post your schematic here.

 

[jxdking]

My old abandoned thread. The tricky part is to bias it in class B.

J

Thread 'Amplifier with 2 AA battery'

2013-03-15 10:27 pm

Output swing: +-1V
Output current: >500mA

I was amazed my 5 inches shelf speaker can play pretty loud with just 2 AA battery.

This kind of out put stage seems to work pretty well with full swing of power supplier. I am thinking about to up scale it to larger power.

PS: It is able to work in Class B, with extremely low distortion.

• jxdking

 

[lineup]

That is nice @jxdking
Clever design and it is more extrem than my circuit.

I forgot to mention that my circuit is Rail to Rail output.
+/-1.92V at +/-2.0V supply into headphone 300ohm.

 

[lineup]

I post your schematic here.
jxdking low volt amplifier +/-1.2V

 

[jxdking]

@lineup , thank you. However, I don't really the circuit. I built 4, and hooked them in btl for 2 channels just for the prove of concept.

Here is another design, not from me. It could work in very low voltage too.

G

Post in thread 'Common emitter / source amplifiers, rail to rail output voltage swing'

2021-07-14 7:56 am

Your attachment seems not working.

You are right. Here is the circuit again for the +/- 1.2 V head phone common emitter amplifier.

• gunterflunder

The long tail from LTP can be swapped out with a trimmable current source for bias stability.

 

[jxdking]

My new design, with 2 batteries.
Biased at 70mA, thus, 1Vp into 8 Ohm in Class A, -63dB THD.

 

[No ideas]

It works down to +/-2.0V.
Distortion is low and current consumption is only like 3-4mA depending on the status of the batteries.
Has been tested in simulation with 32ohm and 300ohm load.

I challenge everybody to try to design a real lowpower headphone amp for +/-2.0V.
Post your schematic here.

View attachment 1431466

do we need the bd transistors at such low supply voltages?