4x RCA to HDMI for Quadraphonic Record Player / Quad Demodulator to Use On HDMI Only System

[ClassicalSurroundFan]

fwiw i ditched Behringer some time ago and have been using a MOTU UltraLite interface the last few years for various Multichannel applications, including 4-channel Quad transfers and haven't looked back

I also use a 2015 Ultralite to my Mac for recording purposes. I have an AVB Ethernet line to a Motu Monitor 8 for output in the home theater though. Sounds fantastic. In addition to my MCH files, I stream 5.1 from Apple Music and concerts from the Berlin Phil.

As you suggest, OP doesn’t need the output power (or any output), or the capacity of such $$$ units, just to get the analog in to his computer…

 

[DudeRocks]

Or, use an interface that has four line inputs with selectable level and select -10dBV rather than +4dBU, then set to unity gain.

Like the Korg 888 lol
EDIT, wouldn't the gain on the front of the UMC4040 help with the level? Or is level and gain separate functions?

 

[ClassicalSurroundFan]

Like the Korg 888 lol
EDIT, wouldn't the gain on the front of the UMC4040 help with the level? Or is level and gain separate functions?

It isn’t really about gain or level (which are indeed two separate things) but more about having the best electronic compatibility, ie. impedance and voltage. Imagine, for example, plugging an electric guitar straight in to an AVR. You would hear almost nothing because the impedance from the guitar is too high and the voltage is too low. This is a more extreme example of incompatibility than we are talking about, which I think would be the difference between a good sound and a great sound.

 

[jimfisheye]

There isn't anything wrong or degraded with unbalanced connections either. Balanced simply offers passive RF rejection and a few more volts to define the signal with. Lets you run audio 100' with no penalty. Unbalanced can be just as perfectly silent and full fidelity. You might have to mind your cable orientation and stick to the shortest cables possible. In fact, someone will surely point out that there are examples of unbalanced connections that are more pure than a balanced connection with less amplifier stages in the circuit or sans the transformer for transformer balanced. (Assuming no noise issues in the example.) But there are 1001 examples of noise challenges with unbalanced that simply disappear with balanced and we like that.

All this modern gear supports plugging unbalanced into the inputs and from the outputs with the 1/4" TRS balanced/unbalanced jack. It's made to run unbalanced by shorting the ring (TRS) to ground or pin 3 (XLR) to ground.

If you are capturing analog audio from some older tape deck with unbalanced outputs, use high quality cables as short as you can get away with. Put on some headphones and carefully listen with the volume turned up with no intentional signal. Listen for rf whine/hum. If you hear something, turn the unit 90 deg (or whatever angle) and see if you can make it disappear. (Familiar with electric guitar and rf noise? Like that!)

 

[ClassicalSurroundFan]

There isn't anything wrong or degraded with unbalanced connections either. Balanced simply offers passive RF rejection and a few more volts to define the signal with. Lets you run audio 100' with no penalty. Unbalanced can be just as perfectly silent and full fidelity. You might have to mind your cable orientation and stick to the shortest cables possible. In fact, someone will surely point out that there are examples of unbalanced connections that are more pure than a balanced connection with less amplifier stages in the circuit or sans the transformer for transformer balanced. (Assuming no noise issues in the example.) But there are 1001 examples of noise challenges with unbalanced that simply disappear with balanced and we like that.

All this modern gear supports plugging unbalanced into the inputs and from the outputs with the 1/4" TRS balanced/unbalanced jack. It's made to run unbalanced by shorting the ring (TRS) to ground or pin 3 (XLR) to ground.

If you are capturing analog audio from some older tape deck with unbalanced outputs, use high quality cables as short as you can get away with. Put on some headphones and carefully listen with the volume turned up with no intentional signal. Listen for rf whine/hum. If you hear something, turn the unit 90 deg (or whatever angle) and see if you can make it disappear. (Familiar with electric guitar and rf noise? Like that!)

All this is true, however my point is not primarily about balanced/unbalanced but rather impedance matching. Yes, these inputs support unbalanced signals, but not all unbalanced signals are the same. These are meant for hi-z instruments like electric guitars, so it’s better, in my view, to balance the lines and send them in at mic level. It’s true there is (6db) loss from the DI transformer, which is why you can spend a fortune on these if you want to, but I’m willing to bet the loss is worth the perfect handshake with the interface.

From there, yes, keep the unbalanced cables to the DI as short as possible and go as long as you like balanced to the interface.

 

[jimfisheye]

There is another can or worms to open with "line" vs "instrument" regarding impedance, yes!

Do take a look at a device's combo xlr/trs jack. Sometimes the 1/4" part is wired as a low impedance balanced line input. Sometimes it's wired as a high impedance instrument DI input. (Literally a built-in DI box.)

So RTFM! It will tell you all about it.

Basically 1/4" connectors are the chaos connector! Used for everything from hi z instrument connections to balanced line level to literally amplifier outputs to passive speakers. Oh yeah, and as two channel (common ground) unbalanced stereo jacks. Certain unintended combinations can release the magic smoke from the device.

 

[SeeMoreDigital]

Hmmmm....

What happened to the original topics discussion regarding: "4x RCA to HDMI for Quadraphonic Record Player"?

 

[ClassicalSurroundFan]

Hmmmm....

What happened to the original topics discussion regarding: "4x RCA to HDMI for Quadraphonic Record Player"?

Well, we’re talking about what needs to go between those 4 RCAs and that hdmi. A computer solution is the only idea anyone has, so how best to do that requires a few pro-audio do-dads.

 

[JediJoker]

Mic pres or line inputs, I still think a -10db switch on an interface with four inputs is a bit of an oddity that may be costly, but if you find one, let us know!

You won't find one with a hardware switch, but interfaces with software mixers—like RME with TotalMix FX or Universal Audio (Apollo) with Console—often have selectable line levels for inputs and outputs.

 

[Marconi]

Any luck on hooking your quad RCA anything to your HDMI only system? I'm about to pick up my first quadraphonic record player which includes a built in demodulator, the Panasonic SL-701. I already have a great Dolby atmos 5.1.4 surround sound system, the Onkyo TX-NR7100. It has many "stereo" RCA inputs and many HDMI and even optical but no "5.1" RCA. Recently seen the 5.1 RCA inputs called AC3, if that helps.

What I'm assuming (which seems to cost me time and money) is there may be a receiver out there in the world that we can hook 4 RCA (FL, FR, RL, RR) to the same 5.1 RCA inputs (FL, FR, RL, RR, and ignore the Center and SubWoofer altogether) and this will at least play those 4 channels, ideally this receiver will also have HDMI or Optical out to hook up to my modern receiver. Anyone know if such a receiver or device exists?

I have seen stereo RCA to HDMI and HDMI to RCA, but I have not seen 5.1 RCA to HDMI which would help a great many of people looking to use their current systems.

Any help appreciated.

I have just posted a possible fix for 4.0 sources but wondered if anyone has already tried it.

 

[DudeRocks]

I have just posted a possible fix for 4.0 sources but wondered if anyone has already tried it.

If you have any ideas I'm all ears! Please let me know the link to the fix, it would be very appreciated from many who follow here and all of the quadies out there! I ended up having to make a handmade physical switch box, I believe i have the photos for the thing in this thread somewhere but it's technically 2 switches, each switch flips between two sources (Receiver out) to the same speakers. I just hooked it up to the home theater surrounds for each corner (fronts and rear surrounds) to the quad amp. Then had to buy 4 subwoofers and have them sitting under or next to each corner to make each channel independently handle its own bass. Sounds pretty dang awesome but it's a back burner thing to deal with as I'm getting ready to install my own solar and have been well distracted fixing things around this house we just bought.

 

[Marconi]

If you have any ideas I'm all ears! Please let me know the link to the fix, it would be very appreciated from many who follow here and all of the quadies out there! I ended up having to make a handmade physical switch box, I believe i have the photos for the thing in this thread somewhere but it's technically 2 switches, each switch flips between two sources (Receiver out) to the same speakers. I just hooked it up to the home theater surrounds for each corner (fronts and rear surrounds) to the quad amp. Then had to buy 4 subwoofers and have them sitting under or next to each corner to make each channel independently handle its own bass. Sounds pretty dang awesome but it's a back burner thing to deal with as I'm getting ready to install my own solar and have been well distracted fixing things around this house we just bought.

https://www.quadraphonicquad.com/forums/threads/working-around-lack-of-multichannel-io.36491/

I hope this link works, if not will copy text.