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I purchased an HDMI 3 input 1 output switcher a couple weeks back. Price is just below $40. It is a ViewHD PRO 3X1. Now it switches HDMI sources obviously. It also can strip out audio in surround or stereo format via Toslink optical. In addition it has analog two channel output. So I thought, hey why not treat it as a budget DAC. This is not one of Amir's official reviews.
https://www.amazon.com/gp/product/B00U8WBOOG/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
Now there are some cheap knockoffs out there. Yes, a cheap knockoff of a sub $40 device. Tear down pics show the same board and chips, but severe compromises on the power supply and capacitor decoupling. So if you need one insist on ViewHD, and not other brands that look exactly the same. I kid you not.
As you might expect I was in for some surprises. I fed it signal over the HDMI via my Lenovo laptop with files playing via Foobar 2000 Wasapi (push), as it would not play with WASAPI event. The output was recorded with a Focusrite Forte.
Okay silent noise floor was about -90 db so not bad. Most of it were decreasing tones at 50, 100, 150 and 200 hz all at a bit below 90 db. Odd as I am on 60 hz electricity here. ???
Channel separation was better than 120 db except one channel was 108 db only near 20 khz. Nothing to worry about.
A 1 khz tone had reasonably low distortion, but included all harmonics to 20 khz above the noise floor. Another feature worth noting. See those spurs at 700 and 1300 hz. Here only 80 db down. Apparently jitter. Every tone has those around it, and at 20 khz they reach just over -50 db. This at 44 khz operation. Same situation and same levels, but at 48 khz the spurs are spaced at 100 hz.
Frequency response was flat enough not worry about.
IMD distortion with 18 khz and 19 khz at full scale was not great however. -48 db below signal level for the 1 khz difference signal and similar levels around the tones themselves. You can still see the 50 hz tones and the 300 hz spurs around the high frequencies.
Jitter was pretty high though I didn't put a number on it. The 300 hz spurs above and below were only 67db below a quarter sample rate tone at 44 khz and 100 hz spacing with the same levels at 48 khz. You can also see how wide the spread is and effects the noise floor considerably.
Here is a 20 khz tone (red) and -4db white noise (blue) superimposed with 192khz sampling from the 48 khz test. Also shown is the silent no signal noise floor(green). So you can see something of the filtering and imaging. Not great, but not horrible if not for the jitter effects.
Here is one I like to do and show for how filtering handles signals. You are seeing a real time FFT in this case a 128 K FFT meaning it is grabbing 128 k samples to construct this. The signal is a linear sweep of twin tones separated by 1000 hz.
First the spectrogram in this case from 48 khz of the entire twin tone sweep. You see IMD distortion worsens with frequency and some THD evident too. The background goes to gray at -120 db.
These are a few snapshots during the sweep of the twin tones with 96 khz bandwidth. Interesting how the reflections move as the frequencies move. Also notice even in the below 20 khz range the noise floor gets modulated heavily. Good DACs don't do much of this.
For comparison of the last image here is the same result for the old Tact RCS 2.0 I have on hand. Notice the 1 khz difference tone is below -110 db here instead of the near -50 db of the ViewHD. The two tones show some reflection around the sample rate, but at levels down near -120 db with the Tact instead of the much higher levels and jitter side bands of the ViewHD.
So how does it sound? My subjective impressions (done after measurements were viewed by me). It has a smoothed over sound. Not harsh (which I expected might creep in with the high IMD). It did not image very widely or precisely. So less depth, width and detail with an innocuous sound quality. If you needed it not exactly terrible, but my Nexus 6P smartphone is better and I suspect many phones would be. For TV if you need it okay, but otherwise you can do better. Glad I use the Toslink digital out. Seems fine listened to this way. I haven't checked the jitter via Toslink to see if any of it is slipping thru.
Oh, and as an HDMI switcher it is pretty nice. With a 12 foot cable straight from the satellite source I would sometimes get minor momentary picture tearing effects as if the signal was iffy to my projector. Don't get those with blu-ray or computer sourced HDMI. I chalked it up to satellite. Since getting this switcher and now using a 35 ft HDMI cable to my projector I no longer get those artifacts. So it seems an improvement in that one sense. Switches well with the supplied remote. My only complaint is the remote is too tiny. Smaller than a credit card. Has good range though. The LEDs on front are just right, lit enough you can see them, yet not so bright as to distract during low light viewing.
As an HDMI switcher/digital audio extractor.........
As a low buck DAC........................................................................................................
https://www.amazon.com/gp/product/B00U8WBOOG/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
Now there are some cheap knockoffs out there. Yes, a cheap knockoff of a sub $40 device. Tear down pics show the same board and chips, but severe compromises on the power supply and capacitor decoupling. So if you need one insist on ViewHD, and not other brands that look exactly the same. I kid you not.
As you might expect I was in for some surprises. I fed it signal over the HDMI via my Lenovo laptop with files playing via Foobar 2000 Wasapi (push), as it would not play with WASAPI event. The output was recorded with a Focusrite Forte.
Okay silent noise floor was about -90 db so not bad. Most of it were decreasing tones at 50, 100, 150 and 200 hz all at a bit below 90 db. Odd as I am on 60 hz electricity here. ???
Channel separation was better than 120 db except one channel was 108 db only near 20 khz. Nothing to worry about.
A 1 khz tone had reasonably low distortion, but included all harmonics to 20 khz above the noise floor. Another feature worth noting. See those spurs at 700 and 1300 hz. Here only 80 db down. Apparently jitter. Every tone has those around it, and at 20 khz they reach just over -50 db. This at 44 khz operation. Same situation and same levels, but at 48 khz the spurs are spaced at 100 hz.
Frequency response was flat enough not worry about.
IMD distortion with 18 khz and 19 khz at full scale was not great however. -48 db below signal level for the 1 khz difference signal and similar levels around the tones themselves. You can still see the 50 hz tones and the 300 hz spurs around the high frequencies.
Jitter was pretty high though I didn't put a number on it. The 300 hz spurs above and below were only 67db below a quarter sample rate tone at 44 khz and 100 hz spacing with the same levels at 48 khz. You can also see how wide the spread is and effects the noise floor considerably.
Here is a 20 khz tone (red) and -4db white noise (blue) superimposed with 192khz sampling from the 48 khz test. Also shown is the silent no signal noise floor(green). So you can see something of the filtering and imaging. Not great, but not horrible if not for the jitter effects.
Here is one I like to do and show for how filtering handles signals. You are seeing a real time FFT in this case a 128 K FFT meaning it is grabbing 128 k samples to construct this. The signal is a linear sweep of twin tones separated by 1000 hz.
First the spectrogram in this case from 48 khz of the entire twin tone sweep. You see IMD distortion worsens with frequency and some THD evident too. The background goes to gray at -120 db.
These are a few snapshots during the sweep of the twin tones with 96 khz bandwidth. Interesting how the reflections move as the frequencies move. Also notice even in the below 20 khz range the noise floor gets modulated heavily. Good DACs don't do much of this.
For comparison of the last image here is the same result for the old Tact RCS 2.0 I have on hand. Notice the 1 khz difference tone is below -110 db here instead of the near -50 db of the ViewHD. The two tones show some reflection around the sample rate, but at levels down near -120 db with the Tact instead of the much higher levels and jitter side bands of the ViewHD.
So how does it sound? My subjective impressions (done after measurements were viewed by me). It has a smoothed over sound. Not harsh (which I expected might creep in with the high IMD). It did not image very widely or precisely. So less depth, width and detail with an innocuous sound quality. If you needed it not exactly terrible, but my Nexus 6P smartphone is better and I suspect many phones would be. For TV if you need it okay, but otherwise you can do better. Glad I use the Toslink digital out. Seems fine listened to this way. I haven't checked the jitter via Toslink to see if any of it is slipping thru.
Oh, and as an HDMI switcher it is pretty nice. With a 12 foot cable straight from the satellite source I would sometimes get minor momentary picture tearing effects as if the signal was iffy to my projector. Don't get those with blu-ray or computer sourced HDMI. I chalked it up to satellite. Since getting this switcher and now using a 35 ft HDMI cable to my projector I no longer get those artifacts. So it seems an improvement in that one sense. Switches well with the supplied remote. My only complaint is the remote is too tiny. Smaller than a credit card. Has good range though. The LEDs on front are just right, lit enough you can see them, yet not so bright as to distract during low light viewing.
As an HDMI switcher/digital audio extractor.........
As a low buck DAC........................................................................................................
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