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Topic: How to connect differential audio amp to zero DAC? (Read 1 time) previous topic - next topic

lemming

Nov 07, 2017, 05:42 am Last Edit: Nov 07, 2017, 06:31 am by lemming
I was wanting to connect a cheap 100W mono audio amplifier to the DAC of my zero. The amplifier uses a TPA3116D2 chip  http://www.ti.com/lit/ds/symlink/tpa3116d2.pdf which has a differential input. Do I need any passives between the zero and the amp or do I connect the DAC of the zero to input '+' of the amp and zero ground to input '-' of the amp?



The board is this one:
 https://www.ebay.com.au/itm/TPA3116DA-DC-12V-24V-100W-Mono-Channel-Digital-Power-Audio-Amplifier-Board-BDAU/361997922456?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D48793%26meid%3D79ee2ee5354546fa86179b22191e49de%26pid%3D100010%26rk%3D3%26rkt%3D6%26sd%3D272760348113&_trksid=p2047675.c100010.m2109

glovisol

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I connect the DAC of the zero to input '+' of the amp and zero ground to input '-' of the amp?


Do you really mean: ....I connect the DAC to the OUTPUT '+' of the amp and zero ground to OUTPUT '-' of the op amp?

Sulimarco

#2
Nov 07, 2017, 02:31 pm Last Edit: Nov 07, 2017, 07:56 pm by Sulimarco
Hi Lemming,

the answer is in the  TPA3116D2 datasheet  at paragraph  7.3.7,  page 16:


Quote
To use the TPA31xxD2 family with a single-ended source, ac ground the negative input through a capacitor equal in value to the input capacitor on positive and apply the audio source to either input. In a single-ended input application, the unused input should be ac grounded at the audio source instead of at the device input for best noise performance. For good transient performance, the impedance seen at each of the two differential inputs should be the same. 
Regards
Marco

lemming

#3
Nov 09, 2017, 01:23 am Last Edit: Nov 14, 2017, 11:16 am by lemming
Thanks Marco,

I'm still not clear what this means but have given it my best shot in the attached png.

Is this the correct way to hook them up?


lemming

Bump.  After finally getting the PNG to upload.

Sulimarco

Hi Lemming,

the attachment is a very crude sketch, that shows how, in my opinion, to connect the Zero Dac to the differential input of your ampli.

I take for granted that the two capacitors are already present in the ampli board.

If the Zero and the ampli are more than few centimeters far I suggest you to use a twisted pair cable for the audio signal, as shown in the sketch.

Let me know if this can help you.

Marco

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