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New FIFO buffer for RPI/SBCs
New FIFO buffer for RPI/SBCs
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Old 24th March 2017, 11:18 AM   #811
doctormord is offline doctormord  Germany
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Are the measurements posted here:
http://www.diyaudio.com/forums/vendo...ml#post5028480

done at 19V or a higher voltage?
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Old 24th March 2017, 11:25 AM   #812
cdsgames is offline cdsgames  Canada
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using the same SMPS at slightly lower than 19v
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Old 24th March 2017, 11:51 AM   #813
doctormord is offline doctormord  Germany
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Hmm, Poutmax at 8R:

(19V*0.707)^2/8R = 22.5W

From the plots reading for 1% THD:

20Hz: 28W
1kHz: 26W
6kHz: 26W

Ok.
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Old 24th March 2017, 01:42 PM   #814
cdsgames is offline cdsgames  Canada
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Quote:
Originally Posted by doctormord View Post
Hmm, Poutmax at 8R:

(19V*0.707)^2/8R = 22.5W

From the plots reading for 1% THD:

20Hz: 28W
1kHz: 26W
6kHz: 26W

Ok.
You are very precise by looking at that graph. 26W

I get slightly lower . But yes seems that they used higher voltage. I know the smps has a +- (10-15%) but frankly we work in different offices and a while back they told me we use 19v. Seems they used 5 to 10% more.
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Old 24th March 2017, 02:12 PM   #815
doctormord is offline doctormord  Germany
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Yes, it's more like 25.25W.

I did some more measurements on the Sanwu with different inductors, getting it quite close for loads >=8R with the right inductor to your pace. Will post that stuff in the other tread.
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Old 24th March 2017, 02:17 PM   #816
cdsgames is offline cdsgames  Canada
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Close..but no cigar ?

Also I assume you are also using normal SMPS as power source to reach close like we do? Or is it a lab PSU/linear ..

Just to compare apples to apples.
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Old 24th March 2017, 02:23 PM   #817
cdsgames is offline cdsgames  Canada
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Stepped attenuator for Volt+ released :-)

10k , 0.1% thin film resistors , 25ppm
https://allo.com/sparky/stepped-attenuator.html

Next week we will test the Volt+ using the new attenuator. All test on Volt+ were done with POTs . Lets see if we get any improvement ..
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Old 24th March 2017, 02:30 PM   #818
doctormord is offline doctormord  Germany
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Quote:
Originally Posted by cdsgames View Post
Close..but no cigar ?

Also I assume you are also using normal SMPS as power source to reach close like we do? Or is it a lab PSU/linear ..

Just to compare apples to apples.
Close yes - because i don't have an AP to work with and i can't specify the uncertainty of measurement. I also don't know what integration time and window function the AP is using for the FFT. Beside this, i don't have exact 8R load resistors.

(Lastly, i compared at 1kHz only)

The results are reasonable as a colleague did measured his TPA3118 implementation in the same manner with "close" results.

Power supply is a Korad KA3005D. (Linear)

Last edited by doctormord; 24th March 2017 at 02:32 PM.
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Old 24th March 2017, 02:44 PM   #819
cdsgames is offline cdsgames  Canada
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Our testing is done with SMPS. I think its slightly unfair to use a linear power supply and compare the data versus one using SMPS..generally speaking

Second , you are comparing BTL with PBTL boards. You know that PBTL have better specs.

Even with that, from 0.1W to 22W our boards show better THD+N.

So we will take it.
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Old 24th March 2017, 02:47 PM   #820
doctormord is offline doctormord  Germany
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Life's unfair.
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