TAS5706 simple full digital stereo amplifier

Now TAS5706 amplifier is playing great music from small board :)

I think TAS5706 can be final solution for Stereo Full digital Amplifier for DIY.

please see my website for detail, and hi res photos.

If anyone want to be group by manager, I can provide ExpressPCB CAD data. ( I don't want to be.. )
 

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Wow you're working hard on this! Impressive!

A question; does using SMD components provide advantages concerning RF? I'd assume that with a low density PCB like this it would have been possible to make use of larger sized resistors, which would make it a bit more accessible for DIY'ers?

Wouldn't it make sense to add more ground plane areas on the top side of the PCB, in addition to the bottom?

Also, what kind of power supply would you recommend? A 12v STEPS setup? What's the maximum current draw?
 
TheMG said:
I'm impressed by the fact you managed to etch your own PCB with enough precision for that IC!
This is made by ExpressPCB, I'm not etching for these years. (messy chemical, drilling...)

panomaniac said:
Are you using the on chip volume control? Is that working for you?
Yes on chip digital volume control works fine, than Apogee DDXi.

iampivot said:
does using SMD components provide advantages?
more ground plane areas on the top side of the PCB?
Also, what kind of power supply would you recommend?
What's the maximum current draw?
Soldering 0805 is not difficult, and it can provide small footprint / without hall, wireing freedom / cheaper / small storage in my desk.
ground plane on the top works nice at 4 layer board, but small meaning for 2 layer.
Power supply can be 12V, from generic wall adapter to Lab DC power, maximum about 2A. Or you can use Battery, Or if you need more power, you can supply up to 24V.

I'm using small DC Lab power supply, spec 18V/3A. for desktop usage, TAS5706 uses 11V / 100mA.
 
iampivot said:
Can your design take 18v regulated in order to deliver the maximum 20w output?

Yes that's why 5V regulator is switching. no overheating by high supply voltage. you need heat sink for high power.

speakerguy79 said:
Have you tried using an FM radio anywhere near it?

no noise. but I didn't try AM radio, see datasheet, there are AM interference related register setting.
 
You seem to be on a roll here. :)

You believe your TAS4i sounds better, might it be because it has better jitter suppression, or just due to the output stage being different?

How about adding a USB audio input in addition to spdif, or use a SRC4392 as you suggested?

Also, how about adding a digital volume pot, should be easy to do with some PIC code?
 
iampivot said:
You believe your TAS4i sounds better, might it be because it has better jitter suppression, or just due to the output stage being different?
How about adding a USB audio input in addition to spdif, or use a SRC4392 as you suggested?
Also, how about adding a digital volume pot, should be easy to do with some PIC code?

Hi I tested now,
(a) single channel, TAS-4i (TAS5518+TAS5142)
(b) TAS5706
... and I'm not sure I can pass blindfolded test. TAS5706 is worthy adversary with LINN Acurate212.
(a) pros: Power supply voltage control.
(b) pros: closed loop. newer design?

TAS5706 board has external I2S input, so if I have time I can try something other than CS8416.

Last night I posted initial version PIC source code, with volume control and input selection, to my website.
 
Fantastic work Koon,
I'd be very interested in how the I2S input sounds - supposedly cleaner/sharper/clearer than SPDIF

Both this & USB input could be achieved with PCM2706/7 USB chip

Are you using the same variable PS vol control as used on the TAS-4i?

Any idea of offering a group buy of boards when project is finished? This would give something back to you for all the work you are putting in & allow interested (but not as competent as you ) DIYers, like myself, to build something similar!

Edit: I'm currently modding the guts out of a Panasonic SA-XR57 multichannel amp based on the TAS5076/TAS5182 Equibit chips. Would love to build one of your TAS5706 amps as a reference to compare against & as a great 2 channel amp! http://www.diyaudio.com/forums/showthread.php?s=&threadid=115276
 
jkeny said:
Are you using the same variable PS vol control as used on the TAS-4i?
Any idea of offering a group buy of boards when project is finished?

Hi thanks for interest,

TAS5706 does not require variable voltage, it takes 10-26V range fixed. Now I'm using $199 Lab DC supply, 18V/3A, as 12V ps.

I will try to connect I2S later, from my SD card player, and USB I2S device. ...By my SD card player, I can try whole DIY full digital, no AC, no motor audio system:)

For group buy,, just a while until I order box & satisfied for inspection. I have 2 boards so I can send 1 to someone.

Then I need someone who could
(1) re-inspect. at least measure THD/N, temparature, waveform.
(2) re-make. order sample board / parts / assemble / listen.
by these step you can think this amp is reproductive.
(3) manage group buy. too much job for me.
 
Hi Koon,
I would be interested in the spare board if I pay you + shipping - I'll PM you.

I have a 100MHz osc but haven't used it yet - I'd have to get up to speed in using it to do some measures but I'm willing.

Edit: I can see this amp being very popular to the DIY community so a group buy will probably be very appreciated!
 
Hi jkeny
don't be so upset... this amp's birthday is just 1 week ago.
I have parts for spare board, so initial tester will receive completed one, at free. no money required but...

I hope initial tester can,
measure THD/N with some frequency / output watt
look wavesforms around circuits, and judge against datasheet
measure thermal temparature at high watt usage
re-program PIC when I updated firmware
point out improvement on schematic / board

it will take about 1-2 weeks until I get enclosure and panel, misc parts, listen many CDs, measure around.
 
KOON3876 said:
Hi, what is "digital volume pot" you mean?
TAS5706 contains digital volume and I'm controling it by PIC.
just writing volume value to TAS5706 0x07 register.

Just an optical rotary switch, eg something like http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=EM14C0D-E28-L064N-ND

Each clockwise click would generate an up impulse, and counter-clockwise would generate a down impulse. The PIC code could simply update a counter and write the register. This is similar to how the volume wheel on a tact M2150 works.

A bit more detailed: http://www.circuitcellar.com/library/print/0303/millier152/2303017.pdf

A thread with some info here: http://www.diyaudio.com/forums/showthread.php?threadid=958