Photos

bare board

assembled : tested

I2S LRCLK and SDATA

LRCLK and PWM output


The minimalism? dsPIC SD-I2S player, direct connection to TAS5706.
1. SD Card has wav file
2. dsPIC33 reads wav, output I2S.
3. TAS5706 gets I2S, drive speaker.

with DC supply, Pioneer full-range speaker.

 Box

inside

Back

Playing with Battery. Ni-CD or Ni-MH is better than Auto 12V because of high current output.

Brief

DIYAudio thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=119917
There were TI's newsletter to my inbox, about "TAS5706 single chip full digital amplufier".
I thought TAS5518 and TAS5412 are too much complicated for DIY.
I can not explain how to build TAS5518 amplifier. it took some months to complete.
TAS5706 can be nice reference for DIY.

Actually it was easy.. I got board at Friday, Now Saturday, It's playing Bach So Great.

Schematic & BOM

page1 Power and reset
page2 CS8416
page3 TAS5706
page4 PIC18F1320

BOM

Just a copy  from reference design, and my previous work.
Power supply is intentionally overspeced, I think this is very important point.
(or in other word, there are nothing to care about, in Full digital amplifier :)

Board Image



Eurocard sized.

Software

 Now under constructing but it's easy,
  1. Write 0x85 to CS8416 register 0x05. I2S, 24 bit output.
  2. Write 0x89 to CS8416 register 0x04. Channel 1 input.
  3. Write 0x00 to TAS5706 register 0x1B, to enable factory PLL trimmer.
  4. Write 0x00 to TAS5706 register 0x05, to activate all channel.
  5. Write 0x64 to TAS5706 register 0x07 as adequate initial value of master volume.
Only one struggling was 3. PLL factory prerecord recovery. This is new function than TAS5518. I coudn't notice for a while.

If you want to modify EQ, IIR BiQuad, DRC,....
please see my TAS5518 controller source code.

03/23/2008 current source, volume and OPT/COAX select

THD Measurement

Not an accurate. for rough indication.
Input = WaveGene + Edirol UA-1Ex Optical,
condition = 4W output to dummy load, Channel 1, (DC cut 1uF Film),
measure = UA-1 Ex + WaveSpectra
 4W THD THD+N
400Hz 0.018% 0.050%
1kHz 0.020% 0.080%
4kHz 0.073% 0.167%

Screen: 400Hz / 1kHz / 4kHz

Noize at 60Hz can be seen also UA-1EX self loopback, so it effects result.

Maybe my design is not spoiling TAS5706.

Enclosure

 BOX: Hammond 1455Q1601 from Mouser electronics, $22
 Panel: made by Front Panel Express. 4 panel total = $95.

I recommend Front Panel Express, High quality top accuracy alminum panel, with reasonoble price. You will get exactly as you ordered. I no more do drill by myself.

Conclusion

This amplifier is cheap (about < $100, Parts $50 and Board was $60 for protptype ),  sounding incredible. I don't know how to write this clearness / naturalism.
It sounds like your CD player was directly connected to your speaker.
(I believe... my TAS4i is sounding better, but it is 4 way IIR divided)

I bought QUAD L-ite speaker for this amplifier.  It's dangerous, I'm almost satisfied and less willness to go other projects.


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