hello!
it's been quite a long time since i had been here.
well, i want to build the noise cancelling headphones too. i stopped at the Headwise project. and was wondering if there would be any difference in using TL074(or TL072) instead of the NE5532.
i know that the NE5532 has lower noise, but i cannot tell how low, and if it would make much of a difference. the problem would not be the cost, but i have to order it online, and probably the shipping would be more than 3 of those IC-s. but i have a couple of TL074 around and a TL072.
a friend of mine suggested using a TCA5500 for the headphone op-amp, wich also has a little equalizer. do you think that that would be better?
i was wondering if anyone around here has build a headphone noise cancelling circuit, and what the results were. i am not going to use expensive headphones, and want do do the project for my computer, to have teh headphones around. the idea is that sometimes there is too much noise and i have to turn the phones louder to hear it well, so this is not a good idea for my health.
i have build the final stage from that circuit using half of a TL074, and with the input shorted, i couldn't hear anyting in the headphones, but if i connected an audio cable(and the other end was loose) then much noise was picked up. i can also say that i tested it with a cd-player, and the noise of the playes itsself was increased significally.(when using the player directly, if there was no sound and no noise around i could hardly hear the noise, but when i added that amplifier then the noise was easilly hearable). the headphones i have used are 32 ohm, and i have to say that the distorsion seemed quite big at high volume. maybe this could be because the TL074 cannot supply enough current. for powering the amp, ia have used +/-9V for powering up the circuit.