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-   -   DIY AD1853 and AP measurement (http://www.diyaudio.com/forums/digital-source/80253-diy-ad1853-ap-measurement.html)

banana 25th May 2006 04:13 PM

DIY AD1853 and AP measurement
 
2 Attachment(s)
Share with you guys my diy AD1853 DAC.

Simple design, no ASRC or reclock.
DIR1701 > AD1853 > OPA2604 I/V > OPA2604 LPF

There is an Elma selector and a DACT volume pot at the output.

banana 25th May 2006 04:19 PM

2 Attachment(s)
Here it is the AP2 measurement with 16bit input.

input 16bit/48KHz, 0dBFS
Analog output 4.0Vrms (volume pot at maximum)
measurement bandwidth 20KHz
THD+N = 0.002%

banana 25th May 2006 04:20 PM

2 Attachment(s)
FFT 16bit input.

banana 25th May 2006 04:22 PM

2 Attachment(s)
Again with 24bit/48KHz input.

THD+N = 0.0006%

jan.didden 25th May 2006 04:23 PM

Hello banana,

Looks good! But the real test is, how is it doing at -40dB, -60dB and -80dB full scale?

Jan Didden

banana 25th May 2006 04:51 PM

2 Attachment(s)
FFT for 24bit input.

Now the noise floor is down and you can see harmonic more clearly.

Compare with the AD1853 datasheet, K2 is similar.
But I would like to see less high order harmonic.

And the left channel is noticeably worst.

ezkcdude 25th May 2006 04:57 PM

Banana, you have some nice DIY speakers on your website. I built speakers with the SS8554 as well. Are you going for a complete DIY stereo system? That's my goal.

banana 25th May 2006 05:06 PM

2 Attachment(s)
Hi Jan,

For 16bit input, THD+N rise to about 1%. But all harmonic hidden below noise floor so i didn't save the plot.

I didn't know how to measure pure harmonic instead of THD+N with AP2.

Maybe averaging would help.

Here is the front view.

Bernhard 25th May 2006 05:09 PM

Banana,

could you please measure with -60dB dithered signal ?
Look on Pedja's page, there is download, would be nice for me for direct comparison. :rolleyes:

http://www.pedjarogic.com/files/1kHz...ed_nshaped.zip

The bad thing about >16 bit DACs - as you noticed :D - is that distortion becomes more noticeable because of the lower noisefloor :dead:

banana 25th May 2006 05:21 PM

Quote:

Originally posted by ezkcdude
Banana, you have some nice DIY speakers on your website. I built speakers with the SS8554 as well. Are you going for a complete DIY stereo system? That's my goal.
Ezkcdude, that 8554 was made long time age and the foam surround is deteriorating. I would use 1 inch dome to mate with 8554 instead if i was to do it again.

There's more if you can read Chinese. My next target is UCD400 and Manger active 2-way, but it already took me to long to build.

12M4631 3-way
Manger never completed


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