HDMI To Optical Stereo

[Wombat]

To temporarily address a hum-loop between my analogue stereo system and my Blu Ray DVD/SACD, HDCD, etc. player I thought I could use one of these with a DAC.

https://www.monoprice.com/product?p_id=13348

I have seen posts on-line where they are good for extracting audio from copyright-compliant players.

Any chance of a test here? User comments?

 

[amirm]

I am sure it will produce sound. Is this for critical listening or just movie sound? If the latter, I would not bother with testing it. Just use it. For former, I doubt it is that good.

At $39 it doesn't make sense to pay to ship it back and forth for me to test.

 

[NorthSky]

Yes, I have couple questions.
How is your equipment plugged in; in the same power bar, and what is the limitation of the music material you are listening to?

 

[Wombat]

Yes, I have couple questions.
How is your equipment plugged in; in the same power bar, and what is the limitation of the music material you are listening to?

My audio system. including the multi-format disc player/recorder, is in one room plugged into an outlet behind it. The TV and the antenna booster are in another room plugged into another outlet on the same circuit. Possible causes: two players on one outlet each connected via HDMI to the TV on another outlet, The antenna/booster earthing, outlet earthing.

Normally the player is used for video replay and disconnected from the audio system to prevent hum. I am going to have some more outlets installed and the house earthing checked. I counted 17 mains plugs - too many power boards. This is not the problem as the audio system is quiet at idle butrather messy and not as safe as I would like.

Because the equipment stand(6 ft. high shelf unit) will have to be move, the electrical work will have to wait for now.

I mainly play cds but the player in question plays my few high resolution discs. I could just use this player for audio and another for the TV but I am an Electrical Engineer and would rather fix the root cause of the problem - just not now.

 

[NorthSky]

It reads...complex.

Can your antenna booster create the hum? But then, I am asking this to an electrical engineer.
You are familiar with the potential hum from using different outlets, and from different rooms.

You like jazz?

 

[Blumlein 88]

You could read my review of a similar device.

https://www.audiosciencereview.com/...ewhd-prosumer-ultrahd-hdmi-3x1-switcher.1560/

Of course it is a measurement review of its analog output. I do however mostly use it as you wish to do. I plug HDMI sources into it, and use the optical out to feed an old AVR that has digital Toslink, but no HDMI. I then use the HDMI output to switch sources for a projector in my video rig. I use it on a Fire TV stick, satellite TV box and bluray player. I presume you only need the optical output to prevent the hum. If you intend to use it with the direct analog outputs I expect it will be okayish, but definitely not great.

I seems to work and sound just fine. It will pass at least 5.1 Dolby digital as well as stereo. The Blackbird is a similar item and should accomplish what you wish. Monoprice is good too, if it isn't satisfactory I believe they would allow a return.

 

[Wombat]

It reads...complex.

Can your antenna booster create the hum? But then, I am asking this to an electrical engineer.
You are familiar with the potential hum from using different outlets, and from different rooms.

You like jazz?

 

[Wombat]

I should have been more clear. The antenna booster is on one circuit and split-feeds an AVR connected to one mains circuit and the TV on the other mains circuit.

I think that the outlet grounds are at fault but it could be something else. I'll clean and tighten up the mains outlet ground connections and plug connections before I call in the man with the tester. One of the many power-boards could be the culprit. Lots of possibilities, some more likely than others.

I like jazz.

 

[Wombat]

You could read my review of a similar device.

https://www.audiosciencereview.com/...ewhd-prosumer-ultrahd-hdmi-3x1-switcher.1560/

Of course it is a measurement review of its analog output. I do however mostly use it as you wish to do. I plug HDMI sources into it, and use the optical out to feed an old AVR that has digital Toslink, but no HDMI. I then use the HDMI output to switch sources for a projector in my video rig. I use it on a Fire TV stick, satellite TV box and bluray player. I presume you only need the optical output to prevent the hum. If you intend to use it with the direct analog outputs I expect it will be okayish, but definitely not great.

I seems to work and sound just fine. It will pass at least 5.1 Dolby digital as well as stereo. The Blackbird is a similar item and should accomplish what you wish. Monoprice is good too, if it isn't satisfactory I believe they would allow a return.

Thank you for the review. Just what I wanted.

Are there better performing ones available?

 

[Blumlein 88]

Thank you for the review. Just what I wanted.

Are there better performing ones available?

I don't know, though I assume they vary. I don't know how much it matters if they will put out a good Toslink signal if that is what you are using. I could do a basic J-test jitter measurement of the one I have using Toslink to feed a DAC and see if the switcher box gives a different result vs being fed Toslink from a Musical Fidelity V-link converter. Let me know if that is desired.

Toslink will get the proper bits thru, it is inherently isolating of hum problems you are fighting, so unless it messes up the timing seems like it would be at least pretty good.

 

[Wombat]

I don't know, though I assume they vary. I don't know how much it matters if they will put out a good Toslink signal if that is what you are using. I could do a basic J-test jitter measurement of the one I have using Toslink to feed a DAC and see if the switcher box gives a different result vs being fed Toslink from a Musical Fidelity V-link converter. Let me know if that is desired.

Toslink will get the proper bits thru, it is inherently isolating of hum problems you are fighting, so unless it messes up the timing seems like it would be at least pretty good.

That is a generous offer but I think I can use the inexpensive one with a very basic DAC I have until I fix the hum problem. My OPPO player's DAC will be then OK to feed the RCA inputs on my stereo amp.

 

[Sal1950]

I seems to work and sound just fine. It will pass at least 5.1 Dolby digital as well as stereo. The Blackbird is a similar item and should accomplish what you wish. Monoprice is good too, if it isn't satisfactory I believe they would allow a return.

Are the original data rates preserved with these type of devices, or do they all get resampled to some base number like 44K?

 

[oivavoi]

I don't know, though I assume they vary. I don't know how much it matters if they will put out a good Toslink signal if that is what you are using. I could do a basic J-test jitter measurement of the one I have using Toslink to feed a DAC and see if the switcher box gives a different result vs being fed Toslink from a Musical Fidelity V-link converter. Let me know if that is desired.

Toslink will get the proper bits thru, it is inherently isolating of hum problems you are fighting, so unless it messes up the timing seems like it would be at least pretty good.

I would appreciate that, Blumlein88!

 

[amirm]

Are the original data rates preserved with these type of devices, or do they all get resampled to some base number like 44K?

Depends on whether they follow the rules or not. The rules say that any content that is copy protected (e.g. Blu-ray/UHD) cannot have an unprotected digital output that has sampling rate above 48 Khz. If you play say a Blu-ray with 96 Khz sample rate, the device must convert it to 48 Khz. You are then at the mercy of how good the sample rate converter is inside this little device.

There are boxes that throw out the rule book and do illegal things like outputting the video over component/VGA which have no copy protection. As such, it is possible for these devices to output the original bit stream as is.

It is really hard to tell what is inside these things without testing them.

I can go ahead and buy one of these boxes, test it and then send it to OP if there is sufficient interest. If so, let's make sure I buy the one that we think is good to test. Let me know.

 

[Blumlein 88]

Are the original data rates preserved with these type of devices, or do they all get resampled to some base number like 44K?

Well the one I have only has HDMI for inputs. So everything ends up 48 khz. I could send a 44 signal over HDMI (or I think I did that once with my computer). I don't know about 96 khz. I can give it try though I doubt it works at that sample rate. I have a busy couple of days starting today. I'll provide what info I can when I get some spare time which might be later tonight.

 

[RayDunzl]

I have a busy couple of days starting today.

I'd blame that on your new dress.

Not sure why you chose to colorize yourself, though...

 

[NorthSky]

What if you play a Blu-ray Audio or DVD Audio disc @ 96 or 192Khz and it would be real nice for your trustable ears, after years of mastering the art of listening from the best sources, to get the full canopy of the recorded high audio resolution...

Best would be to buy a new receiver/pre-pro with HDMI inputs and with all the hi-res audio decoders inside...from all sources including SACD, and files too, ...DSD, FLAC, WAV, etc.

The HDMI connection simplifies the hires and hidef transmission signals, from one single cable only. It is digital and all type of room correction EQ can be used.

Is it a question of money that we have to accept an inferior sound quality; if it is c'est comme dommage. The digital optical connection in this case here is restricted in its resolution. We are not taking advantage of the HDMI thruput connection...HDMI in > HDMI out.

Also, having the source, the display, the receiver or pre/pro, external DAC, AMP, etc., in the same room simplifies the audio signals transmission, consequently preventing hum and sound degradation.
And same for the video signals.

 

[Blumlein 88]

I'd blame that on your new dress.

Not sure why you chose to colorize yourself, though...

Seemed like a waste of a good HDMI connection to stay b&w.

 

[Fitzcaraldo215]

I should have been more clear. The antenna booster is on one circuit and split-feeds an AVR connected to one mains circuit and the TV on the other mains circuit.

I think that the outlet grounds are at fault but it could be something else. I'll clean and tighten up the mains outlet ground connections and plug connections before I call in the man with the tester. One of the many power-boards could be the culprit. Lots of possibilities, some more likely than others.

I like jazz.

Like you, I think the outlet grounds on different power circuits are at fault. Rather than spinning wheels trying some cheap device that may or not work, and which might compromise sound quality, I would simply run a room to room extension cord, plugging both systems into the same electrical circuit.

If it works, unplug and roll it up when not in use. Eventually, do the necessary adjustments at your main circuit box with your now proven concept.

This happened to me between my PC in the neighboring room to my USB DAC, which was on a different power circuit. The extension cord fixed it, and it now runs through a hole in the wall.

 

[amirm]

Disconnect the coax cable from your TV and see if the hum goes away.