It might work but I would advise capacitors to couple the input signal and possibly a load resistor across the input to keep the phone happy. It also depends what op-amp you plan to use. Some are only for very low level signals or have very restricted bandwidth.
Brian.
thanks mr KlausHi,
I agree with the capacitors.
I recommend to use a dedicated earphone amplifier. Usual Opamps may have problems to drive that low impedance with output close to the supply rails.
Maybe use class D amplifier with low pass filter.
Klaus
someone set behind keyboard wait for reply from he's admire teacherHi,
Because humans have two ears, I assume most earphone amplifiers come with two channels.
Klaus
thanks mr d123Hi,
"Wide Power Supply Range:
Application areas include transducer amplifiers, dc
– Single Supply: 3V to 32V gain blocks and all the conventional op-amp circuits
– Or Dual Supplies: ±1.5V to ±16V"
If the input only goes to -0.7V on +-3V, you're fine. The -0.3V means not exceeding an additional +-0.3V beyond the +-supply rails on the inputs.
I'm not sure but I'd check that the output can actually go to +-2.8V, if not then extend the supply or lower the output if possible, or just switch to a rail-to-rail (input and) output op amp. One of the experts here will know better if the op amp fits the input and output range.
LM158
from post #5Hi,
I assume there are class D earphone 2 channel ICs.
Did you do a search? At manufacturers and/or distributors...
Klaus
thanks mr AudioguruYou want the 0.7V RMS amplified 3 times so the output must be 5.94V peak-to-peak.
Don't use a lousy old LM158 because it has crossover distortion and its output swing will be much less than the 6V p-p required so it will produce horrible clipping distortion.
I think any amplifier will not produce a rail-to-rail output swing when loaded with 600 ohms. Then increase the supply voltage or reduce the input and output levels.
I thought about a PAM8403 stereo class-D little amplifier but it is designed for a 5V supply and your 6V is too high for it.
i want very few component and lite circuit
This class D amplifier is made from a 555 timer IC. It's simple, inexpensive and useful to experiment with.
The 555 is configured as a pulse generator. An audio signal is applied to the 'control' pin, causing the duty cycle to grow or shrink.
The output is PWM. By filtering it becomes a close match to the original audio.
View attachment 148945
picture's attached
i read PAM8403 data sheetI thought about a PAM8403 stereo class-D little amplifier but it is designed for a 5V supply and your 6V is too high for it.
right to ground ~= 0.7vInterested to know the mapping between these two pictures. Is differential Input of 0.7V is mapped to Left/Right of the universal 3.5mm Jack?
thanks youThe datasheet for the PAM8403 recommends a max supply of 5.5V. Your coin batteries will produce 6.4V when new.
You can use a voltage divider to reduce the battery voltage only if the current in the divider is very high that will kill your batteries in a few minutes because a voltage divider that powers something that has a variable current is a poor voltage regulator.
Its inputs are not differential, each amplifier is bridged so the outputs are differential. The bridged outputs cannot drive headphones that have a ground, coupling capacitors can feed half the bridge to each headphone.
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