Yes, correct: Bluetooth headphones will have a DAC and an amplifier built into them.

But the second question, if I understood correctly, you're asking if you have a pair of Bluetooth headphones which also have an analog input, if you could plug another pair of headphones into that input and it would act as an output? The answer is most likely not. It would depend on how the circuit is designed but any reasonable headphone manufacturer will disable the Bluetooth if the analog connector is enabled.

If you're asking can you tear open a pair of Bluetooth headphones to get to the DAC and amp inside, then sure. But you can probably just buy the same chip off AliExpress for less money and hassle.

>wired headphones do not have built in dac because the signal they receive is already analogue

Yes

>Bluetooth headphones gave a dac because bluetooth transmission is digital so they have to convert it?

Yes

>Also could you theoretically utilize headphones built-in DAC if they are wired and would it be better than integrated dac in the motherboard?

I think so, yes. Integrated dac in the motherboard might have noise in it, so headphones built-in DAC might sound better. To connect such wired built-in DAC headphones with a PC, USB or other digital cable would be required.

> Also could you theoretically utilize headphones built-in DAC if they are wired

You could, if you connect them to digital output (USB). You will bypass the builtin DAC if you use the 3.5mm input on the headphones and 3.5mm output on the motherboard - because that's already analogue signal.

Shit, if that's what you understood from the second question, then my English is worse then I thought xD. Byt being serious, what I meant was when you have a pair of Bluetooth headphones which also have analogue input (I have m50xbt2 for example), if you connect them to your computer by cable (headphone output), is there a way to use their built in dac. In other words transmit a signal (via this cable) that is digital so that it will be converted by the headphones itself and not the motherboard's dac before, or does the headphone dac work only while Bluetooth is on?

Yeah usb indeed, thanks.

Thanks for answering

No, there is probably no protocol, e.g. digital audio protocol, that the headset would receive over the analog cable. Also, it is usually not described if the analog audio will be used and sent to amplifier, or whether it needs to be digitized first. Chances are that the amplifier in the headset is class D and it can only work from digital signal (it is both a DAC and amplifier at the same time).

At least noise cancelling headsets usually have wildly different frequency response when you turn them on vs. when you connect analog to driver and drive it directly. I can't quickly find out the answer to this question: does the sound change if the headset is turned on vs. off? In the headsets I have owned that have had optional wired connection, the sound has always been absolutely terrible when powered off because manufacturer actually fully relies on DSP (or whatever amplifier circuit) to fix the frequency response of the driver.

Right, gotcha. Analog inputs in general wouldn't be tied to the digital input of the DAC (this will be true regardless if you're talking about a pair of headphones or any other device), and besides your computer's motherboard wouldn't be able to output a digital signal from the headphone socket*.

(Well, with one caveat: in the past some manufacturers had a combo analog + Toslink connector - Toslink is optical digital connector so your receiving device needs an optical input.)

>Also could you theoretically utilize headphones built-in DAC if they are wired and would it be better than integrated dac in the motherboard?

You could, but it depends. There are some gamer USB headsets that most likely have a DAC inside them but I doubt it would be a good one. Apart from that your only chance is probably wireless headphones that can also be used wired, and those are also pretty rare (and most likely won't use their DAC when wired).

Really given that a $10 apple dongle is very good for the size/price there's little reason to depend on any headphone -internal DAC unless it's wireless.

Thanks

Thanks

Look at the Focal Bathys, it basically uses this idea: have a DAC built in because Bluetooth, but also allow the headphone to be used with a usb cable to receive a lossless, digital signal that the built in DAC also handles.