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Old 14th April 2017, 04:02 PM   #471
JPS64 is offline JPS64  Germany
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... I/V with low leakage current capacitors...

JP
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Old 14th April 2017, 06:02 PM   #472
jborden is offline jborden  United States
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Quote:
Originally Posted by JPS64 View Post
Hello JAB.R
How do you solve the mute problem?
JP


That is best solved in the USB->DSD or Ethernet->DSD driver.

The original glue logic from the DSC1 could be included.

At the driver level there are optimizations available including providing a clock family signal as well as soft start/dithering etc that can solve clicks at rate/song transitions.

I'm not sure where Amanero etc are in this. I've set mine aside as I'm working on the direct Ethernet->DSD route.
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Old 1st May 2017, 08:48 PM   #473
ppy is offline ppy  Russian Federation
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I measured the balanced version of DSC1 with SRC AK4137:

Resistors installed other - 8.25K 0.1%
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Last edited by ppy; 1st May 2017 at 09:06 PM.
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Old 2nd May 2017, 03:18 AM   #474
Terry Demol is offline Terry Demol  Australia
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Quote:
Originally Posted by ppy View Post
I measured the balanced version of DSC1 with SRC AK4137:

Resistors installed other - 8.25K 0.1%
Well done!

The noise looks fairly high compared to most modern DACs but distortion
looks very good.

- Is this at max OP
- Were you using AK4137 to convert to DSD for DSC1?

cheers

T
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Old 2nd May 2017, 07:53 AM   #475
ppy is offline ppy  Russian Federation
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Quote:
Originally Posted by zenelectro View Post
The noise looks fairly high compared to most modern DACs but distortion
looks very good.
I think that the noise level below 120db satisfies the parameters of high-quality sound reproduction.
Quote:
Originally Posted by zenelectro
- Is this at max OP
What is "OP"? I make measurements always at -10db. This is similar to the average weighted level of most music records.
Quote:
Originally Posted by zenelectro
- Were you using AK4137 to convert to DSD for DSC1?
Yes, I use AK4137 to convert PCM to DSD. The output format was set by DSD128. DSD256 slightly increases THD from 0.00086% to 0.0018%.
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Old 2nd May 2017, 12:51 PM   #476
Terry Demol is offline Terry Demol  Australia
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Quote:
Originally Posted by ppy View Post
I think that the noise level below 120db satisfies the parameters of high-quality sound reproduction.
If the 'grass' or noise floor on FFT is around -120dB then that does not mean
the RMS noise floor is -120dB. 20k BW RMS noise floor will be around -100dB
depending on the no of points of FFT sweep. A DAC that has true -120dB
noise floor will show the FFT 'grass' at around the -150dB level with a 20k
BW sweep.

Many people get fooled by this and many manufacturers misquote their
performance specs due to this misunderstanding. That's just noise theory.

Quote:

What is "OP"? I make measurements always at -10db. This is similar to the average weighted level of most music records.
Yes, OP = Output. The reason I asked is because at 0dB (full scale) is where
most DAC's struggle WRT distortion and it can rise significantly.

Quote:

Yes, I use AK4137 to convert PCM to DSD. The output format was set by DSD128. DSD256 slightly increases THD from 0.00086% to 0.0018%.
Interesting WRT DSD 256. I would expect the opposite but it might be
related to logic switching finite speed.

WRT resistor matching, on this design it should not make any significant
difference, that's just the way the moving average filter works.

Overall though a pretty good result. I think to get better measured performance than this on a discrete design would take some real design
effort.

- Which clocks are you using and..... most importantly...
how does it sound?

T
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Old 2nd May 2017, 01:51 PM   #477
Signalyst is offline Signalyst  Finland
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Quote:
Originally Posted by zenelectro View Post
If the 'grass' or noise floor on FFT is around -120dB then that does not mean
the RMS noise floor is -120dB. 20k BW RMS noise floor will be around -100dB
depending on the no of points of FFT sweep.
0.000857% THD+N gives -101.34 dB as total noise level for the measurement bandwidth, including distortion.
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Old 2nd May 2017, 02:06 PM   #478
ppy is offline ppy  Russian Federation
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Quote:
Originally Posted by zenelectro View Post
Yes, OP = Output. The reason I asked is because at 0dB (full scale) is where
most DAC's struggle WRT distortion and it can rise significantly.
That's measured with -0db level without AK4137. The DSD128 dsf file is converted from WAV by the saracon program.

Quote:
Originally Posted by zenelectro
Interesting WRT DSD 256. I would expect the opposite but it might be
related to logic switching finite speed.
I also think that the problem is speed.
Quote:
Originally Posted by zenelectro
WRT resistor matching, on this design it should not make any significant
difference, that's just the way the moving average filter works.
Lowering the output resistors of the matrix improves the matching with the 10K transformer.
Quote:
Originally Posted by zenelectro
- Which clocks are you using and..... most importantly...
how does it sound?
Amanero with Crystek.
Both versions - balanced and not balanced - have a strongly pronounced analog sound. I would call it "vinyl sound". I really like him.
The non-balanced version is a little in the lead in subjective comparison. But in a non-balanced version, the correlation noise at low volume is annoying.
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Old 2nd May 2017, 02:22 PM   #479
Terry Demol is offline Terry Demol  Australia
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Quote:
Originally Posted by ppy View Post
That's measured with -0db level without AK4137. The DSD128 dsf file is converted from WAV by the saracon program.

I also think that the problem is speed.

Lowering the output resistors of the matrix improves the matching with the 10K transformer.

Amanero with Crystek.
Both versions - balanced and not balanced - have a strongly pronounced analog sound. I would call it "vinyl sound". I really like him.
The non-balanced version is a little in the lead in subjective comparison. But in a non-balanced version, the correlation noise at low volume is annoying.
WRT 0dB FS - that is an excellent measured result.

Are you feeding the transformer from after opamp I-V or are you just feeding
resistor matrix straight into transformer?

I think this design needs to feed virtual ground for best performance.

Edit - PS I think also the results can be skewed by ADC in test set (EMU?)

Nice results!
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Old 2nd May 2017, 02:28 PM   #480
ppy is offline ppy  Russian Federation
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Quote:
Originally Posted by zenelectro View Post
Are you feeding the transformer from after opamp I-V or are you just feeding
resistor matrix straight into transformer?
Transformers are connected directly to the resistors.
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Last edited by ppy; 2nd May 2017 at 02:31 PM.
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