Introducing miniStreamer: Native 24/96 USB to I2S / SPDIF interface - Page 3 - diyAudio
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Old 22nd April 2011, 04:10 PM   #21
zog666 is offline zog666  Australia
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Originally Posted by minidsp View Post
Great info, thanks for the follow up. If you have any additional info to share on how you set it up, it will be useful info for the community.

Thanks for sharing the info again,

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it pretty much "just works", at least with the pulsaudio service that recent Ubuntu linux ships with. It shows up as a soundcard, and you can use the pulsaudio mixer applet to select it as an output.

I've just ordered an SP/DIF stereo ADC from ebay, will play with using it to record once it arrives as well.

I still haven't used it beyond 16 bit 44.1khz, havent worked out how to set Pulsaudio to do it.. and all my source FLAC files are 16/44100 so in no hurry to do so.
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Old 28th April 2011, 01:14 AM   #22
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How about some DIY info, I'd like to build one.

Does anyone know about a project like this one? I wanna be able to stream a high bitrate signal to my ADAC's from my D/A and A/D converters and have that come and go through USB or firewire through WDM/directsound and even ASIO. I'd even write the drivers if necessary but it'd be nice to know that it's possible.

Thanks
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Old 28th April 2011, 04:12 AM   #23
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I'm interested in integrating a USB input into my exisiting DIY DAC. It accepts S/PDIF and I2S, would the miniStreamer be appropriate? I'm currently using a Hagerman HagUSB, which is limited to 16/44.1 input and S/PDIF output, and the miniStreamer is attractive because of the 24/96 input capabilities and the I2S output.

If it is possible to use the miniStreamer in this way, what hurdles would I encounter using it's I2S output into the DAC?

Thanks in advance.
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Old 4th May 2011, 02:11 AM   #24
minidsp is offline minidsp  Hong Kong
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@Strider75,

I don't see any problems for you to integrate your miniStreamer to your DIY DAC. Have a look at the user manual, it's only a couple of lines with I2S, and only GND/SPDIF out for SPDIF so even easier. :-)

Hope this helps,
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Old 27th May 2011, 03:27 PM   #25
JensH is offline JensH  Denmark
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I have used the miniStreamer to connect some ADC and DAC boards (24 bit) to my Windows XP PC. At the moment I am using the I2S Interface. I am using the ASIO4ALL driver.
I have some questions related to the miniStreamer.

I use an FFT program on the PC as generator and analyzer. I have it working on both output and input at 48kHz. If I set up the generator to output a 1kHz sine wave at -90dBFS the output I get is quite distorted, since there are only 4 discrete levels on the analog signal, as if it has only a 16 bit resolution. The Windows volume control is set to maximum in this case.

If I output a 1kHz signal at -30dBFS and turn down the Windows volume control to -60dB I get a nice sine wave output.

Do you have any explanation for this?
Is there a volume control in the TE7022L which is used by Windows? Is there a limited resolution on the USB output?
The developer of the analyzer SW claims that in his SW everything is computed in floating point format and output with a resolution of 24 bit.

As stated the miniStreamer is always the clock master on the I2S interface. Not necessarily ideal, but that is how it is. But what happens if the SPDIF input is used? Will it lock to clock of the incoming audio stream or will it add/skip samples or resample in some other way?
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Old 31st May 2011, 03:21 AM   #26
minidsp is offline minidsp  Hong Kong
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@ Jens,

I'm not 100% sure to understand your question here so may need some clarifications.. :-) -90dBFS is very low by all means.. I'm not sure what you're trying to get out of that signal but Typical DR results are measured as per AES17 by applying -60dBFS and then adding 60dB to the reading you're getting. What's with the -90dBFS measurement for? (i.e. you shouldn't be able to hear anything at that level on any DAC/ADC, so close to noise floor)

As for Windows, it does apply a volume control (I believe showing as Line in in the sound card?) Anyway, once we understand the question (and reasoning behind measurement) we can try to answer your question.

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Old 31st May 2011, 07:01 PM   #27
JensH is offline JensH  Denmark
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I know that -90dBFS is low, but with a 24 bit converter there should still be a fairly good resolution. Disregarding the noise for a moment, it should be possible to get e.g. a sine wave with a 9 bit resolution with a signal level of -90dBFS.

My set up is like this: the generator signal goes from the PC via USB to the MiniStremer, via I2S to a 24 bit DAC, from the DAC to 24dB gain stage before a 24 bit ADC, via I2S to the MiniStreamer and back to the oscilloscope/FFT analyzer on the PC.

I have attached two figures. In both cases the red trace is the interesting one.
The one with a distorted signal shows the signal I see when setting the Windows volume control to maximum and the generator to -90dBFS. As it can be seen there are only 4 quantization steps (+ some noise which could be from the DAC and ADC.
The one with the clean signal is with an analog signal (from a R&S UPL Audio Analyzer) into the 24 dB gain stage and the ADC. This is to verify that the distortion is not caused by the ADC. As can be seen the signal looks OK in this case.
The scale on the left is the same in both figures.

If I set the generator at -30dBFS and the Windows volume control at -60dB, this should also give a level of -90dBFS. It does and in this case the signal looks OK.
Attached Images
File Type: jpg Distorted signal.jpg (97.4 KB, 530 views)
File Type: jpg Clean signal.jpg (109.9 KB, 526 views)
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Old 28th July 2011, 04:59 PM   #28
jacko is offline jacko  United States
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will the streamer work with the 2x8 board as well?
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Old 28th July 2011, 06:03 PM   #29
tresch is offline tresch  United States
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Quote:
Originally Posted by JensH View Post
I know that -90dBFS is low, but with a 24 bit converter there should still be a fairly good resolution. Disregarding the noise for a moment, it should be possible to get e.g. a sine wave with a 9 bit resolution with a signal level of -90dBFS.

My set up is like this: the generator signal goes from the PC via USB to the MiniStremer, via I2S to a 24 bit DAC, from the DAC to 24dB gain stage before a 24 bit ADC, via I2S to the MiniStreamer and back to the oscilloscope/FFT analyzer on the PC.

I have attached two figures. In both cases the red trace is the interesting one.
The one with a distorted signal shows the signal I see when setting the Windows volume control to maximum and the generator to -90dBFS. As it can be seen there are only 4 quantization steps (+ some noise which could be from the DAC and ADC.
The one with the clean signal is with an analog signal (from a R&S UPL Audio Analyzer) into the 24 dB gain stage and the ADC. This is to verify that the distortion is not caused by the ADC. As can be seen the signal looks OK in this case.
The scale on the left is the same in both figures.

If I set the generator at -30dBFS and the Windows volume control at -60dB, this should also give a level of -90dBFS. It does and in this case the signal looks OK.
Could it be that it's a limitation with the generator? I.e. the generator is only generating a 16bit signal.
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Old 30th July 2011, 04:30 AM   #30
i2k92 is offline i2k92  Indonesia
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I'm thinking of buying the ministreamer to connect my PC to my DAC as my existing USB > SPDIF interface only support up to 48KHz.

Next step would be to connect the streamer to Twisted Pear's Opus DAC via I2S. But the I2S inputs on Opus (BCK, MCLK, LRCK, DIN, GND) and outputs on the streamer (are labelled differently).

My guess :
Streamer Opus
MCLK ------------------> MCK
LRCLK ------------------> LRCK
SCLK -------------------> BCLK (unsure)
SDOUT -----------------> DIN (unsure)
GND --------------------> GND

streamer set as master

I'm a newbie on digital electronics, could you pls confirm if the scheme above is correct ?

I also plan to upsample using software and next would be to get an ASRC board and connect it between streamer and DAC. Is it a feasible scenario ?

thanks in advance.
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