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Hosa CDL-313 S/PDIF-AES Interface

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I'm looking at this:

 

https://hosatech.com/products/digital-audio/s-pdif-interfaces/cdl-313/

 

I'm wondering if anyone's tried to use this with the L6 link input on the Helix. Does it work? I want to feed my Helix an S/PDIF signal from a Kemper. I've read about S/PDIF to AES/EBU and understand that some times it works and some times it doesn't, and it's kinda down to the implementation of the standards in a given device. I'm just trying to see if anyone already tried it before I go ahead and do so myself.

 

I'm trying to bring the number of AD/DA conversions in my rig down.

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On 4/23/2019 at 9:23 AM, feffa86 said:

I'm looking at this:

 

https://hosatech.com/products/digital-audio/s-pdif-interfaces/cdl-313/

 

I'm wondering if anyone's tried to use this with the L6 link input on the Helix. Does it work? I want to feed my Helix an S/PDIF signal from a Kemper. I've read about S/PDIF to AES/EBU and understand that some times it works and some times it doesn't, and it's kinda down to the implementation of the standards in a given device. I'm just trying to see if anyone already tried it before I go ahead and do so myself.

 

I'm trying to bring the number of AD/DA conversions in my rig down.

 

I'm confused here. Why would you need to spend $100 on a digital interface to convert a signal that can be converted just fine in the Kemper. If you have the LT, there is no XLR input so this device wouldn't work anyway, but even if it did have one, I don't know that an AD/DA conversion is inferior to a SPDIF to AES digital to digital conversion. 

 

If you have the full blooded Helix, and you want to use S/PDIF, then why not connect from the Kemper S/PDIF output to the Helix SPDIF input?

 

If you have the Helix LT, then why not just use the Kemper standard 1/4 out to the Helix LT standard 1/4 in? 

 

Also, the L6 link is an output, not an input, and is only used in certain Line 6 applications. 

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On 4/27/2019 at 12:29 AM, Kilrahi said:

 

I'm confused here. Why would you need to spend $100 on a digital interface to convert a signal that can be converted just fine in the Kemper. If you have the LT, there is no XLR input so this device wouldn't work anyway, but even if it did have one, I don't know that an AD/DA conversion is inferior to a SPDIF to AES digital to digital conversion. 

 

If you have the full blooded Helix, and you want to use S/PDIF, then why not connect from the Kemper S/PDIF output to the Helix SPDIF input?

 

If you have the Helix LT, then why not just use the Kemper standard 1/4 out to the Helix LT standard 1/4 in? 

 

Also, the L6 link is an output, not an input, and is only used in certain Line 6 applications. 

I have the Helix rack version. I just checked, you're right, it's not an L6 link input, it's an AES/EBU input.

I can't use the Helix S/PDIF input because in the global settings, you have to set "Digital" to either "AES / EBU" or "S/PDIF" and one disables the other. I have two Powecab Plus' that I run from the L6 link output (which even gets expanded upon in the next firmware patch) so that's why I have to use the AES / EBU input. I've done some reading, and AES / EBU and S/PDIF may be cross-compatible or it may not. Some times it is, some times it isn't. There's the sound data and some header data, and depending on the header data, the receiving unit may or may not be able to interpret the signal. Also, the resistance is different in S/PDIF and AES / EBU cables which seems to make a difference if I am to trust people more experienced with these kinds of crossovers than me. I think a custom made AES / SPDIF cable is an untidy solution, and like I said, research seems to suggest it could end up not even working. I'm not sure there actually is a digital-digital conversion with this box, I think the box just does something to the header data. I don't really exactly know what it does, but I know it's meant for interfacing exactly like the way I'm trying to do. Different units with different I/Os. I may be a little off, maybe you don't call it header data, I didn't graduate in this, but that's the jist of what I found out.

 

I can interface ANY unit with only S/PDIF outs to my Helix. Or my Helix to ANY unit that only has S/PDIF inputs, while using my Powercabs. That's the worth of the box. If it ends up causing a mere 1ms lower total latency in my rig that'll be an added bonus, and I know it'll have an effect on the tiny amount of hiss I do get with the Kemper noise reduction set to off.

 

I am already using standard 1/4". That's what I want to not do, if possible.

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Try to make RCA to XLR adaptor with RCA tip connected to XLR hot and XLR cold not connected. It can work just fine.

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On 5/16/2019 at 5:56 PM, zolko60 said:

Try to make RCA to XLR adaptor with RCA tip connected to XLR hot and XLR cold not connected. It can work just fine.

RCA S/PDIF and XLR AES cables have different resistances. I was assured by people more knowledgable than me that that was sub-optimal.

 

So I got this box finally. The power adaptor doesn't work in the EU, but I was able to get a universal wall wart at a regular all supply store and that worked just fine. Eventually I'll get a better one, like maybe the iFi iPower. I falsely assumed the 9V DC input would accept guitar pedalboard power supply cables, but it didn't. It's a smaller type of plug.

 

So it works just as advertised. Kemper S/PDIF out goes into the box and an AES cable goes into the Helix AES/EBU input. The Helix picks up the signal fine and everything works as expected. One less AD/DA round in my rig now. Too bad the Helix can't run both S/PDIF and AES at once or I could eliminate one more.

 

I just realized, since I'm already using my 1/4" main Left output to feed the Kemper, I now have two extra FX loops available in the Helix with this box. That's another reason to shell out the 100 I didn't even consider.

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21 hours ago, feffa86 said:

I was assured by people more knowledgable than me that that was sub-optimal.

Yes there will be people who claim that you can't directly connect an SPDIF output to an AES input.
But most modern gear will accept SPDIF and AES interchangebly. Don't dismiss it until you have tried it.

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6 hours ago, zolko60 said:

Yes there will be people who claim that you can't directly connect an SPDIF output to an AES input.
But most modern gear will accept SPDIF and AES interchangebly. Don't dismiss it until you have tried it.

https://www.rane.com/note149.html

 

It's not that I didn't think it wouldn't work, or couldn't have tried.

 

IF (BIG if) you know that either the transmitter or the receiver is transformer coupled and the interconnect distance is short then a simple resistor divider will match the impedances and change the level as shown in Fig. 1. This is the AES3id recommended network for creating a 12-dB pad (4:1 voltage divider) and converting the AES3 110 ohm balanced output impedance into 75 ohms for driving the AES3id input. Therefore an average output level of 4 volts will be reduced to 1 volt. Since this exceeds the max allowed for S/PDIF, use the values shown in parenthesis to create an 18-dB pad (8:1 voltage divider) producing 0.5 volt output for the same 4 volts input. (Other average AES3 output voltages require different resistors -- consult AES3id for value graph).

Transformers make the best passive impedance matchers, plus provide the benefits of ground isolation, high-frequency rejection, DC blocking and short-circuit protection. Impedance matching is easily handled by selection of the appropriate turns ratio (1.21:1 for 110-ohm to 75-ohm -- it's the square of the turns ratio for impedance) and careful attention to winding details allow wideband high-frequency transformers (you need ~12.5 MHz). The best and safest converter includes the transformer.

If you are not sure about the transformer isolation of the equipment interfacing, use a store-bought impedance matching transformer that comes complete with connectors and a separate resistor voltage divider network as shown in Fig. 2. This T-network is a 75-ohm:75-ohm bi-directional attenuator. The attenuation is a little less than that of Fig. 1 for the same (assumed) 4-volt AES3 input because the transformer reduces the voltage level by a factor of 1.21:1 (down to 3.3 volts) as well as matching the impedances.

 

If you're still reading, the point is, the box takes care of a number of signal integrity issues that I would have to learn and understand a bunch of stuff i'll never use for anything but this single conversion in my rig to overcome. It cost the same as about two mogami cables, I have about 10 of those in my rig. I didn't want "works", I wanted "optimal solution". :P It has active electronics, so it kinda works like a line isolator with respects to ground.

 

I haven't yet done any latency tests but S/PDIF and AES have the same kind of data code for the sound. The difference is header data. So there's nothing being converted. Maybe header data is being stripped. It makes no sense that there's any latency induced by the design. I can't tell a difference before or after, but presumably there's a couple ms less lag in my signal. There, at the very least, is no more lag than there used to be. It is a known fact that AD/DA causes a bit of hissing noise. So there's a tiny amount less hiss in my setup. I'm not sure I even have a noise floor any more.

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Yes I understand what you mean. You have spend 200$ for DSP converter and this is probably the best solution. I have been connecting AES sources to SPDIF receivers using simple adapters for 20 years. For up to 3m cable runs I don't care about cable impedance or matching transformers. SPDIF to AES/EBU should be even simplier, but if you can afford the best, safe, stable solution I am happy with you.

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