Line out, Line in and Headphone connections

[Panu]

Hi!

The VS1053/VS8053 Simple DSP Board's application note is a great example for how to design a device with good analog performance (sound quality). It's good reading, and it's available at: http://www.vlsi.fi/en/support/evaluatio ... board.html. Look for the Application Note link at the top-right corner of the page.

Here's a small contribution to the discussion about the analog connections. I've annotated a section of the Simple DSP Schematic, showing what the various capacitors and resistors in the analog block are actually for.

Have fun examining!

VS1053-Analog2.png (202 KiB) Viewed 21608 times

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For a good example of connecting to a D class amplifier, please take a look at the schematic at http://www.vlsi.fi/fileadmin/software/V ... der_03.pdf. That D class amplifier connection has good sound quality and has been used by many customers.

-Panu

[Greg]

Hi Panu
I am now using this same line out configuration on two VS1053 standalone original prototype boards.
I have tested it on a high end audio systen and the sound is excellent.

Greg

[Panu]

Hi Panu
I am now using this same line out configuration on two VS1053 standalone original prototype boards.
I have tested it on a high end audio systen and the sound is excellent.

Greg

Thank you, Greg, that's great to hear!

-Panu

[PJMonty]

Panu,

Can (or should) this circuit be used with the vs1011e as well? I'm mainly interested in the line out section of the circuit. I'm designing a board now which will be used for line out applications. Should I use this circuit for better performance with the vs1011e?

Thanks,
PeterM

[PJMonty]

Panu? Anyone from VSLI?

I know the thread is a bit old, bit it should have showed up as a new post.

Still want to know how/if this circuit applies to the vs1011e.

Thanks,
PeterM

[Panu]

Hi!

Still want to know how/if this circuit applies to the vs1011e.

Yes, same circuit can be used for all our chips (except for the line in, since VS1011e has none )

-Panu

[PJMonty]

Panu,

Thanks for the info. I didn't want to send the PCB out for fabrication without this information. I will amend my layout today.

I'd like to suggest that this output circuit be included in a revised version of the VLSI datasheets. Perhaps include it as an additional circuit to avoid complicating the basic circuit featuring CPU and MP3 chip already present.

Thanks,
PeterM

[tvali007]

Hello Panu,


I am trying to loop on VS1053 the Analog input(MIC/ANL1) with Analog output (headphone) to make an analog loop inside VS chip but from datasheet registers seems to be impossible. Is there any way from DSP software point of view to do this?
Thanks for detailed pictures provided above and sorry for off topic.

Best regards,
Valentin.

[pasi]

The easiest way to loop analog input to analog output is to start the encoding mode. You don't need to read out the data (and you don't even need to load any patches). Just select for example 48kHz PCM with the correct channel configuration, line or mic (from SCI_MODE), then start the encoding mode (set SM_ENCODE and softreset in SCI_MODE).

If you need to decode at the same time, use the admixer plugin. I think it is possible to use it with the patches package. Just load and start the patches package first, then load the admixer plugin.

[tvali007]

Hi Pasi,

By starting the encoding mode, my analog stream will pass ADC and then will pass DAC and then go to out.
For me sounds like quality loss - Is it true?
For the moment I don't need to mix the stream, I would like to use the microphone amplifier for my analog stream but it seems that there is a HW constraint. Looks that I need to amplify the signal before Line1/2

Thanks,
-Valentin.