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Adjust volume after TI PCM1742 DAC?

B

Boki

Jan 1, 1970
0
Hi All,
A box audio output is TI PCM1742 DAC, I want to connect to low
power speaker ( thin speake ) and I also want the volume is adjustable.

Do I have to add chip ?

or can I only add variable resistor to function that?

1. I have two channels.
2. The resistor can only decrease volume, right? our digital domain
audio signal to DAC already set to maximum, but I feel it is not loud
enoguh.

Could you please advice the method to adjust two channels volume
directly, or advice a chip that is suitable to connect after 1742?


Best regards,
Boki.
 
M

martin griffith

Jan 1, 1970
0
Hi All,
A box audio output is TI PCM1742 DAC, I want to connect to low
power speaker ( thin speake ) and I also want the volume is adjustable.

Do I have to add chip ?

or can I only add variable resistor to function that?

1. I have two channels.
2. The resistor can only decrease volume, right? our digital domain
audio signal to DAC already set to maximum, but I feel it is not loud
enoguh.

Could you please advice the method to adjust two channels volume
directly, or advice a chip that is suitable to connect after 1742?


Best regards,
Boki.
You need a audio power amplifier, say
http://www.st.com/stonline/books/pdf/docs/1458.pdf
will work if you have sufficient power rails
or
http://www-s.ti.com/sc/techlit/szzb002.pdf

The DAC only supplies about .6V p-p, and needs say 20dB gain in the
poweramp
since the DAC has a software volume control in register 16 and 17,
you can connect directly to a power amplifier with using a
potentiometer


martin
 
M

martin griffith

Jan 1, 1970
0
On Thu, 29 Sep 2005 08:58:30 +0200, in sci.electronics.design martin

sorry, left a word out
since the DAC has a software volume control in register 16 and 17,
you can connect directly to a power amplifier with***OUT*** using a
potentiometer



martin
 
B

Boki

Jan 1, 1970
0
Very good reference!

But, do you have suggstion chip? my speaker is about 1W~4W only.
If the amplifier's power is too large, will it affect/burn the speaker?

Best regards,
Boki.
 
M

martin griffith

Jan 1, 1970
0
Very good reference!

But, do you have suggstion chip? my speaker is about 1W~4W only.
If the amplifier's power is too large, will it affect/burn the speaker?

Best regards,
Boki.
sorry, but since you havent specified your power rails, single, or +
and -, power available, etc, its difficult.
just pick something that is easy to prototype, and cheap. Almost
anything will do, since you do not require HiFi quality



martin
 
B

Boki

Jan 1, 1970
0
Hi Martin,
How about TI - TPA6110A2, my target is to adjust 1W mini
speaker.
My power is 5V~12V ( I will change it, if it can help to adjust volume.),
single, 1A~2A.
No Hi-Fi is required.

Thank you very much!

Best regards,
Boki.
 
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