Direct Attach Cable Thread

On 6/27/2024 at 3:28 PM, Superdad said:

 

Hi Charles:

@Mike Rubin is correct, the $8 Amphenol 571540001 cable you linked to is not made with the ClearSkew wire or polyolefin insulation. Here is the data sheet for the Amphenol 571540001.  

https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/cableassemblies/hsio_ca_sfp_plus.pdf

I just bought a one meter of the Ampheon Clearskew off eBay with the correct part # of SF-SFPP2EPASS for a total of $15.50 with tax and shipping. There is one more at the link below, and there is also a seller with a number of new 3m ones as well. Anyway, once I have all in hand I'll give my account of what I think between a basic Ampheaon, a Clearskew Ampheon, and the Cisco, and if there's truly any differences going on. 

https://www.ebay.com/itm/403938596715?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20231207125618%26meid%3Db48725ac0f8443b79f766edfe0ac2937%26pid%3D101875%26rk%3D3%26rkt%3D12%26sd%3D232676398542%26itm%3D403938596715%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3DSimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3CPCAutoWithCassiniEmbRecall%26brand%3DAmphenol&_trksid=p2332490.c101875.m1851&itmprp=cksum%3A403938596715b48725ac0f8443b79f766edfe0ac2937|enc%3AAQAJAAABcLC2%2Ba5TgOFYgIvLQSBIYkURSzHvc7cCccVTU14STgixqt2LHVH3DQgpuMCV11vSwIPgiyFOwqAlvyaCYV%2F3KC%2BV%2Bw2hITE7xTLMc%2FUAdPVM74mBrClyfys6h0qSntiKTtamp%2FwRG%2FuVgTYA%2FQ9W3Ox1vA0GraSb4JMRxeVcTuw%2FbvfsO7mDS6tzWet1HTCrTfW9840tPTREOq3%2BqdJHbJItLN0QyxmJqd543PotCscHRls1hvi2u9TqZiLCF6fMYbb5pXx81Y%2BKkwm6tvPJ4Ad0QwrCRfw5Vgfl2FAd7G%2FNyY7GiLSA%2FdPNRPU6jS2IqKx4qdo4xXH5cEmZcoz%2F5bxYlgVE6cSOG7uc5I7kGGyp97tKfYBIPNQA54S6qHhlc5uGPTDmbsoGUDw7EkCHW9g0HJYxDBxUq%2FXoL7fuJQwVXbFTka4xyEndIbe3a0bqhBAhQFKs6YxNuH%2FH8WWfLIDvvqF8gawfR0MUzSWobbAG|ampid%3APL_CLK|clp%3A2332490&epid=15010825321&itmmeta=01J1GMBTQTXZE8S0V5Z1AYPCP1

On 6/28/2024 at 11:42 PM, SQFIRST said:

They were clearly directional to me. Flipping them around revealed preference of one way.

Sharp observation! I wonder if others will be just as surprised when they give it a try.

Perhaps you could specify the length you attempted or preferred? The 10GTek 10G SFP+ is recommended by the manufacturer for a maximum of 3 meters (for data transmission, of course). Thanks for sharing!

4 hours ago, di-fi said:

Perhaps you could specify the length you attempted or preferred?

They were all 2m.

My thanks to all of the contributors here as you have helped with getting to an improved experience. Look forward to others sharing their journey.

On 6/26/2024 at 11:38 PM, Assisi said:

I listen to a playlist of approx. 60 tracks that I am very familiar with.

Hats off to you! @Assisi as that is a disciplined and patient process. Thanks for sharing your setup and process.

36 minutes ago, SQFIRST said:

Hats off to you! @Assisi as that is a disciplined and patient process. Thanks for sharing your setup and process.

I note in your post above  that the DAC cables you compared are each 2mt.  Was there a reason for that choice of length?  The Cisco that I have is 2mt.  I decided on that length because of the mention that the Melco only comes in that length.  It is said by Melco that the length was best. Maybe it is a magical length.  Whether that is the case or not I do not know. 

The two switches that I connect with a DAC cable are sitting one on top of the other with isolation feet between.  2mt is much more than enough to connect them.

You mention that your comparison DAC cables have a direction outcome benefit.  I mark all cables where there is a choice with in and out and keep it that way.  With several of the Ethernet cables that I have, the shield at one end has been disconnected.  That becomes the receiving end.  I consider that there is a small benefit.

I expect that I will have an opportunity to trial a Melco DAC cable in the next couple of weeks.  A supplier has one on order for me to try.

John

I compared : RJ45 (no name cat5), Optical SFP (Cisco) and Direct Attach SFP (FS)
 my ranking (for my installation): the FS DAC cable in first place then the RJ45 and finally in last position the fiber with Cisco modules (see photo for references)

https://www.fs.com/fr/products/39781.html?attribute=8715&id=2376335

https://taikoaudio.com/taiko-2020/product/extra-dac-cable/

2 hours ago, Philippe Bill said:

 

@Philippe Bill  Are you using an SFP+ 10G Direct Attach Cable in a 1G Port (Cisco)? What Cisco switch is that?

THX

Torben

10 hours ago, Assisi said:

Was there a reason for that choice of length? 

Any shorter was not possible in my case and from reading most of the recommendations, along with the fact that it is copper being used in a highly optimized situation; it made sense that shorter run may be better. 

10 hours ago, Assisi said:

I will have an opportunity to trial a Melco DAC cable

This will be great feedback to have.

11 hours ago, Assisi said:

I note in your post above  that the DAC cables you compared are each 2mt.  Was there a reason for that choice of length?  The Cisco that I have is 2mt.  I decided on that length because of the mention that the Melco only comes in that length.  It is said by Melco that the length was best. Maybe it is a magical length.  Whether that is the case or not I do not know. 

 

 

I don't think there's anything 'magical' sounding in that length. I would go shorter if you can, or longer if you actually need the reach. I think for Melco 2m was probably a good compromise to sell the cable without having to manufacture and stock a number of different lengths. Not too long and not too short. At this point these DAC cables are still very much outliers as most streamers/switches are RJ45 based. But I think as this cat gets out of the bag and the etherRegen 2 comes out we may see that the few of us here are at the forefront of something. Because the difference I'm hearing, from the best optical (AOC) wasn't even subtle, but dramatic. And I doubt any fancy four figure ethernet cable could compete. 

7 hours ago, TRHH said:

 

@Philippe Bill What Cisco switch is that?

a Cisco Meraki MS-220-8 with a diy external linear power supply

8 minutes ago, TRHH said:

Potential pros and cons of using an optical cable versus a DAC

- Any additional information or comments?

 

 

Torben

Shouldn't ground plane noise be reversed?

No for fiber, Yes for DAC.

This is what I came up with while focusing on use of DACs, please correct or clarify:

Galvanic isolation - handled by setup power isolation and any internal handling of the devices in use
Signal conversion - in favor of dac
Electronics - in favor of dac
Ground-plane noise - in favor of dac
Jitter - in favor of dac
Electromagnetic pick up - mitigated by short runs and any manufacturer treatments of the dac
Power consumption - in favor of dac

@TRHH another differentiator would be cost as dacs are relatively cheaper. Not a technical aspect but a difference still.

Thank you for sharing that list and even more so if you compiled yourself.

This is now I use DAC in my setup:

Torben

1 minute ago, TRHH said:

This is now I use DAC in my setup:

Hey another conversion, awesome! Welcome to the dac club :)

My endpoint is a NAA build on a Asus J6412 Celeron IOT board powered by JS-2 (cpu runs at 5watts...). I had some good results using a i350 network card instead of build in realtek RJ45.

Jumping on the bandwagon, I found this i350 based SFP card (https://www.aliexpress.us/item/3256804571195898.html?spm=a2g0o.order_list.order_list_main.5.6e9718020FcVvs&gatewayAdapt=glo2usa). I know, I know, its China ... ;-) 

So I will comapre A->B with Intel i350 RJ45 to NAA with B->A China i350 with DAC ... 

20 minutes ago, SQFIRST said:

@TRHH another differentiator would be cost as dacs are relatively cheaper. Not a technical aspect but a difference still.

@SQFIRST Now with your input :-) And some more from my side :-) Again, suggestions and comments are more than welcome

Torben

@TRHH you wanna add ferrites to the DAC ?!?!

10 hours ago, charlesphoto said:

I don't think there's anything 'magical' sounding in that length. I would go shorter if you can, or longer if you actually need the reach. I think for Melco 2m was probably a good compromise to sell the cable without having to manufacture and stock a number of different lengths. Not too long and not too short. At this point these DAC cables are still very much outliers as most streamers/switches are RJ45 based. But I think as this cat gets out of the bag and the etherRegen 2 comes out we may see that the few of us here are at the forefront of something. Because the difference I'm hearing, from the best optical (AOC) wasn't even subtle, but dramatic. And I doubt any fancy four figure ethernet cable could compete. 

Neither of us know whether the Melco position on the importance of the length of the cable is a benefit or just a compromise as you suggest.  Manufactures constantly make many comments about beneficial aspects of their products.  Unless Melco make cables of different lengths neither of us will know the answer to the question of whether the length is a benefit or not? 

I will be interested in being able to compare the Cisco 2mt DAC cable that I have to the Melco one when I have the opportunity.  The Cisco DAC is an improvement on the  Cisco AOC 1mt that I was using previously.  Is the length a factor?  I do not know.

John

6 hours ago, Mops911 said:

@TRHH you wanna add ferrites to the DAC ?!?!

To the ethernet cable :-)

Torben