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Need best audio amplifier part for my design

user6003289
Prodigy 120 points
Other Parts Discussed in Thread: TPA3110D2, TPA3255, TPA3220, TPA3116D2

Dear All,

We are executing a new design which is based on a sophisticated audio equipment for medical purposes.

Need a audio amplifier which can support 8 Ohm speaker with a audio gain output of around 130dB.

We have seen many of part numbers from TI like TPA3110 but this part is making a "HISSSS" noise even when there is no input signal.

The noise should be zero at any cost to meet our equipment requirement.

Please guide with suitable part number.

Thanks and regards,
Nagendra
ACELOGY SYSTEMS

  • 0
    TI__Guru** 100965 points

    Hi Nagendra,

    Since you mention TPA3110D2, I think you're looking for an analog input device, is this correct?

    I have another question, you mention 130dB gain but what is the actual output power you need on 8ohm speaker? Is your input signal too small? Perhaps you can consider using a pre-amplfiier stage with a low noise op amp and then a power amplifier. This would help to keep noise floor low.

    There are several analog input options from high power, high voltage TPA3255 to something mid-power like TPA3220 or TPA3116D2. However the gain on these devices is around 20~36dB.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Prodigy 120 points

    Hi,

    We are using the audio output generated by a Raspberry Pi, which has an inbuilt preamplifier.

    The audio output of Raspberry Pi will be connected to audio amplifier to support at least 35W power to a 8 ohm speaker.

    We have already tried with different amplifier circuits but the HISSS sound is not getting eliminated.

    Considering these inputs please suggest the audio amplifier part number

    Thanks and regards,

    Nagendra

  • 0 in reply to user6003289
    TI__Guru** 100965 points

    Hi Nagendra,

    One quick suggestion: Have you tried to place a low-pass filter between the output of Raspberry and input of the power amplifier?
    Most likely the output from Raspberry comes from a DAC, if you use a Class-D power amplifier, the modulation will take the high frequency noise from DAC into the audible band. Please try with an RC low-pass filter with cutoff frequency of at least 30~40kHz.

    Please let me know if this solves the hiss sound.
    I'll come back with some part suggestions for 35W into 8-ohm.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Guru** 100965 points

    HI Nagendra,

    Do you have any comments about the last information provided above?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators