EtherREGEN: The long development thread. [Some Gen2 dev. pics and update starting on page 92.]

[nonesup]

Another way for schuko wall sockets

[LowMidHigh]

Back to the LPS-1.2 and the new switch. Is this is the sort of cable to use in order to ground the switch? 

 

Simply connect between the switch and a grounded spot (e.g., bolt on a grounded outlet)? 

[Superdad]

2 hours ago, LowMidHigh said:

Back to the LPS-1.2 and the new switch. Is this is the sort of cable to use in order to ground the switch? 

 

Simply connect between the switch and a grounded spot (e.g., bolt on a grounded outlet)? 

 

Really no need to pay $12 for a few feet of a single conductor of wire.  Just about anything from your scrap drawer will do. 

It is a matter of what plug, spade, or stripped bare wire end you use at the earth point (AC outlet or strip location, or chassis or ground screw terminal on one of your other components), and also a matter of what connection point we provide at the EtherREGEN.

 

I do not want this to become a crowd-design discussion, but I will admit that as of this moment we have not made a final decision as to whether the grounding connection on the EtherREGEN will be a standard 2mm tip jack (in which case we will provide a nice mating solderless tip plug) or if there will be a thumb-screw that will accept a small spade or ring terminal as well as bare wire.

There are logistical design considerations for and against both.  In the end we will choose and it will be easy for users--if they ever need to use the grounding connection.

[R1200CL]

On 1/31/2019 at 3:49 AM, Superdad said:

standard 2mm tip jack 

 

How does it look like ?

 

 

[BlueDL]

I was just looking at the ifi Groundhog, in particular the spade connector option in the array of connections supplied.

Is it merely an IEC socket with the L and N left floating/isolated and the earth connection connected to a chunky gauge wire terminated with a spade? If so, even I could make this for a fraction of the cost without having to by the connections I don’t need!

[JohnSwenson]

9 hours ago, BlueDL said:

I was just looking at the ifi Groundhog, in particular the spade connector option in the array of connections supplied.

Is it merely an IEC socket with the L and N left floating/isolated and the earth connection connected to a chunky gauge wire terminated with a spade? If so, even I could make this for a fraction of the cost without having to by the connections I don’t need!

The problem with doing it yourself is that "spade", I have not seen it anywhere. It is very special, it is designed to exactly fit the barrel and has little protrusions at the end that "click" into place when you place it around the barrel, this holds the spade tightly to the barrel and makes a decent contact. I'll bet that iFi had these spades custom made.

 

John S.

[Superdad]

5 minutes ago, JohnSwenson said:

The problem with doing it yourself is that "spade", I have not seen it anywhere. It is very special, it is designed to exactly fit the barrel and has little protrusions at the end that "click" into place when you place it around the barrel, this holds the spade tightly to the barrel and makes a decent contact. I'll bet that iFi had these spades custom made.

 

Of course not relevant to EtherREGEN because if we provide a ground post with thumbscrew people can use any spade, ring terminal or even bare wire.

[BlueDL]

23 hours ago, BlueDL said:

terminated

Good point!

Please let us know the screw’s outer diameter as soon as the solution has been finalised. As I will have an LPS-1.2 available, I may as well put it to good use.

[greenleo]

Is there any optimal length or minimum length for the LAN cable?

 

Gearing up for the EtherRegen.

[JohnSwenson]

11 hours ago, greenleo said:

Is there any optimal length or minimum length for the LAN cable?

 

Gearing up for the EtherRegen.

It turns out that "normally" there is a minimum length of Ethernet cable  of 1 meter. The PHYs don't work if there is less capacitance  than you get from one meter of cable. BUT since I found out about this I have been adding that amount of capacitance on the boards so it doesn't matter. The EtherRegen will definitely have the caps so there will be no minimum cable length.

 

As to maximum cable length the spec is 100 meters. The longer the cable length the worse the signal integrity. For the EtherRegen the only place that matters is the connection from the EtherRegen to your renderer. On the other side it does not matter. So you want to keep the EtherRegen near the renderer and use a short cable between them. On the other side you can have a long cable. I'm not sure I would go for exactly 100M. I would probably give it a little margin to make sure things work.

 

John S.

[mansr]

2 hours ago, JohnSwenson said:

It turns out that "normally" there is a minimum length of Ethernet cable  of 1 meter. The PHYs don't work if there is less capacitance  than you get from one meter of cable.

I can't find any such requirement in the Ethernet spec or PHY datasheets. I also have never had a problem with cables only a few inches long.

 

2 hours ago, JohnSwenson said:

As to maximum cable length the spec is 100 meters. The longer the cable length the worse the signal integrity.

True, but the 100 m limit is mainly due to propagation delay restrictions.

[diecaster]

19 minutes ago, mansr said:

I can't find any such requirement in the Ethernet spec or PHY datasheets. I also have never had a problem with cables only a few inches long.

 

Some switches mention minimum lengths although Have no specific reference for you.

 

It's certainly fine to use super short patch cables (active device to patch panel) as the patch panel is passive and you get the cable length  from the patch panel to the end active device. But, I always used 1m cables between active devices because I had problems with some switches and routers if shorter cables were used.

[mansr]

11 minutes ago, diecaster said:

It's certainly fine to use super short patch cables (active device to patch panel) as the patch panel is passive and you get the cable length  from the patch panel to the end active device. But, I always used 1m cables between active devices because I had problems with some switches and routers if shorter cables were used.

I'm talking about cables between a NIC and a switch.

 

Unless there's a minimum length mentioned somewhere in the IEEE spec, and I missed it (the maximum length is easy to find), I'd say any device that doesn't work with short cables is broken.

[Miska]

Hmmh, I have pile of 30 cm long CAT6 cables in use at the moment and they've been working fine at 1 Gbps speed for years... Networking gear is mostly HPE and Cisco. Oh, and I usually use cable length detection, so the device doesn't unnecessarily blast on short cables at powers needed for 100 meters... ( -> less radiated noise too)

 

[Superdad]

45 minutes ago, mansr said:

I can't find any such requirement in the Ethernet spec or PHY datasheets. I also have never had a problem with cables only a few inches long.

 

Yeah, we'll you ought not to be surprised at just how much companies leave out of their datasheets! 

I believe John was referring to PHY-to-PHY (with magnetics) minimum distance.  Its not applicable to how EtherREGEN operates internally, but he discovered this while working on a different project.  Ethernet switch chip with built-in PHYs does not like being terminated to another with less than an inch of traces.  So he simulated cable capacitance.  I think his reference to the inclusion of similar "loading" caps on the EtherREGEN are for in case someone decides to use a 6-inch cable on one of its ports.

[mansr]

9 minutes ago, Superdad said:

Yeah, we'll you ought not to be surprised at just how much companies leave out of their datasheets! 

I believe John was referring to PHY-to-PHY (with magnetics) minimum distance.  Its not applicable to how EtherREGEN operates internally, but he discovered this while working on a different project.  Ethernet switch chip with built-in PHYs does not like being terminated to another with less than an inch of traces.  So he simulated cable capacitance.  I think his reference to the inclusion of similar "loading" caps on the EtherREGEN are for in case someone decides to use a 6-inch cable on one of its ports.

Sure, if the PHY he's chosen requires external capacitors to work correctly, it would be wrong not to include them. This is the kind of requirement I'd expect to find in a datasheet or reference schematic. My point is, a device as sold to the end user should not have a minimum cable length.

[Superdad]

9 minutes ago, mansr said:

Sure, if the PHY he's chosen requires external capacitors to work correctly, it would be wrong not to include them. This is the kind of requirement I'd expect to find in a datasheet or reference schematic.

 

Well we expect a lot of things to be in datasheets--and then find they are not!   John runs across this all the time.  The chip companies buy each other up and the engineers and people who were documenting a relatively new part get resigned or laid off.  So much goes unwritten...

 

9 minutes ago, mansr said:

My point is, a device as sold to the end user should not have a minimum cable length.

 

Of course.  And our products do not and will not have a minimum cable length. 

[tims]

Probably showing my ignorance here but my current setup is Audirvana plus for Windows (on a laptop) > IsoRegen > BluWave USB to SPDIF bridge > SPDIF cable > DAC.  My music files are on a USB external hard drive connected to my laptop..

Keeping the current configuration which I really like,  could I put the EtherREGEN somewhere in my system to improve it or is it really only suited to a streaming based setup?

 

Thanks

[diecaster]

9 hours ago, mansr said:

I'm talking about cables between a NIC and a switch.

 

Unless there's a minimum length mentioned somewhere in the IEEE spec, and I missed it (the maximum length is easy to find), I'd say any device that doesn't work with short cables is broken.

 

Well, I managed a datacenter for over 10 years. We found that some switches, including some Cisco and Extreme switches, along with some routers, including Cisco routers, did not always work well with cables less than a meter or so long. That "did not always work well" doesn't necessarily mean they didn't work at all...just not well. We would see a bunch of errors in the port stats. The problem was prevalent enough that we had an unwritten rule to use 1 meter cables between active devices. We used much shorter cables, if we could, when connecting to patch panels.

 

Try living in the real world once in a while....

[bobfa]

13 hours ago, tims said:

13 hours ago, tims said:

Probably showing my ignorance here but my current setup is Audirvana plus for Windows (on a laptop) > IsoRegen > BluWave USB to SPDIF bridge > SPDIF cable > DAC.  My music files are on a USB external hard drive connected to my laptop..

Keeping the current configuration which I really like,  could I put the EtherREGEN somewhere in my system to improve it or is it really only suited to a streaming based setup?

 

Thanks

 

 

 

Without a systems re-design I do not see where you would use the EtherREGEN

[wwc]

19 hours ago, JohnSwenson said:

It turns out that "normally" there is a minimum length of Ethernet cable  of 1 meter. The PHYs don't work if there is less capacitance  than you get from one meter of cable. BUT since I found out about this I have been adding that amount of capacitance on the boards so it doesn't matter. The EtherRegen will definitely have the caps so there will be no minimum cable length.

 

As to maximum cable length the spec is 100 meters. The longer the cable length the worse the signal integrity. For the EtherRegen the only place that matters is the connection from the EtherRegen to your renderer. On the other side it does not matter. So you want to keep the EtherRegen near the renderer and use a short cable between them. On the other side you can have a long cable. I'm not sure I would go for exactly 100M. I would probably give it a little margin to make sure things work.

 

John S.

 I recall advice that Switches (and Servers) are ideally located relatively distant from where components are located (like amps withs transformers producing magnetic fields).  

 

But above we're getting advice that the switch should be close to the renderer (my DAC),

which would end up locating the switch also close to the amp.  So I wonder which might be more  important?   

 

And, is there a certain point where ethernet cable length would meaningfully affect it's performance? 3 meters?, 5 meters?   Or are we talking about more extreme lengths?

[greenleo]

On 2/8/2019 at 3:46 AM, JohnSwenson said:

It turns out that "normally" there is a minimum length of Ethernet cable  of 1 meter. The PHYs don't work if there is less capacitance  than you get from one meter of cable. BUT since I found out about this I have been adding that amount of capacitance on the boards so it doesn't matter. The EtherRegen will definitely have the caps so there will be no minimum cable length.

 

As to maximum cable length the spec is 100 meters. The longer the cable length the worse the signal integrity. For the EtherRegen the only place that matters is the connection from the EtherRegen to your renderer. On the other side it does not matter. So you want to keep the EtherRegen near the renderer and use a short cable between them. On the other side you can have a long cable. I'm not sure I would go for exactly 100M. I would probably give it a little margin to make sure things work.

 

John S.

Thank you John for your reply. 

 

Given that 1m is minimum due to the capacitance requirement, is it advisable to have a 1.2 m cable, say?  Just for the reason of safety margin or the 1m length has already included the safety margin. 

Not sure if all LAN cables are identical in terms of capacitance per unit length.  Are the capacitance CAT5, CAT5e, CAT6, ... dependent?

[diecaster]

Just now, greenleo said:

Thank you John for your reply. 

 

Given that 1m is minimum due to the capacitance requirement, is it advisable to have a 1.2 m cable, say?  Just for the reason of safety margin or the 1m length has already included the safety margin. 

Not sure if all LAN cables are identical in terms of capacitance per unit length.  Are the capacitance CAT5, CAT5e, CAT6, ... dependent?

 

There is no IEEE minimum cable length. But, practically speaking, some devices need cables to be longer than 6 inches so 1 meter is more than long enough. CAT5, CAT5e, CAT6...it doesn't matter.

 

Regardless, John is building capacitance into the EtherREGEN so you can use as short a cable as you want. 

[JohnSwenson]

2 minutes ago, greenleo said:

Thank you John for your reply. 

 

Given that 1m is minimum due to the capacitance requirement, is it advisable to have a 1.2 m cable, say?  Just for the reason of safety margin or the 1m length has already included the safety margin. 

Not sure if all LAN cables are identical in terms of capacitance per unit length.  Are the capacitance CAT5, CAT5e, CAT6, ... dependent?

For the EtherRegen there is no requirement for minimum length. You can run down to a couple inches on any of the RJ45 ports.

 

OTHER devices (not connected to the EtherRegen) may or may not have this minimum length issue.

I checked a bunch of spec sheets for Belden cables a while back and they all had similar capacitance figures. If those are representative of other cables then it probably doesn't matter much what type of cable it is. I can't tell you if some $1000 per foot cable has the same capacitance as Belden cable, the $1000 per foot guys usually don't give hardly any specs and I'm not about to spend my life measuring them.

 

John S.

[tomjtx]

2 hours ago, JohnSwenson said:

For the EtherRegen there is no requirement for minimum length. You can run down to a couple inches on any of the RJ45 ports.

 

OTHER devices (not connected to the EtherRegen) may or may not have this minimum length issue.

I checked a bunch of spec sheets for Belden cables a while back and they all had similar capacitance figures. If those are representative of other cables then it probably doesn't matter much what type of cable it is. I can't tell you if some $1000 per foot cable has the same capacitance as Belden cable, the $1000 per foot guys usually don't give hardly any specs and I'm not about to spend my life measuring them.

 

John S.

 

A subtle comment from a very knowledgeable guy. Plus 1,000 😀