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LM4995: Low power audio amplifier with volume control with simultaneously playback on speaker and headphone.

TapasXplore
Expert 1280 points
Part Number: LM4995
Other Parts Discussed in Thread: LM4865, TAS2521, TAS2505

Hi,

I have designed pre-amplifier for a sound system, now the output from the pre-amplifier will be connected to amplifier to increase the power so that it can be connected to 500mW speaker, with volume control. I am thinking of using LM4995, but there is no separate volume controller, is it possible to change the feedback resistor using pot as a variable resistor to change the output volume. 

I have one more question, is it possible to connect speaker and headphone jack in parallel, as to allow sound to come in both headphone and speaker at same time. I have already read about LM4865, (it has separate volume control function). In LM4865 headphone detect function will disable the main speaker, whenever it will detect the 3.5mm jack, which we don't require. Even after insertion of headphone jack, output should come in both main speaker as well as in headphone also.

Could you please help in proper selection of audio amplifier, Vmin of amplifier should be at least 3.3V.

Regards,

Tapas

  • 0
    TI__Mastermind 20085 points
    Hi Tapas,

    I will be responding the next week with further information.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0
    TI__Mastermind 20085 points
    Hi Tapas,

    As I mentioned in another thread, you could use a pot to control the volume, but the audio quality would get worse to high gain. These devices are designed to get their best performance to low gain. You can use a pre-amplifier in order to set a volume control to these devices.
    You could have a look at the following devices: TAS2505 and TAS2521. They can be configured to use the speaker output and headphone the same time.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0 in reply to José Luis
    Expert 1280 points
    Hi José,

    Thanks for your reply.
    I am not using any controller in my system, will TAS2505 work without microcontroller, how will I control the TAS2505 as I don't have I2C control.

    Can you suggest any analog audio amplifier IC which can power both speaker as well as headphones at the same time.

    Regards,
    Tapas
  • 0 in reply to TapasXplore
    TI__Mastermind 20085 points

    Tapas,

    Unfortunately, we don't have any analog audio amplifier which can handle both speaker and headphone at the same time. But you could use an audio amplifier to handle the speaker and a headphone amplifier.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer