Hi,
I am using a new Rossini Player and a Rossini Clock. I also own an Esoteric P-05X Drive.
I would like to know if I can connect my P-05X to my Rossini Clock.
Rossini Clock is 75 Ohms and Esoteric Drive is 50 Ohms.
It seems impedances don’t match? Is there a problem, and if yes, is there a solution to solve this?
Thanks a lot
Gilles
It would be nice to see what Andrew says about this. My own view is that it won’t matter that much.
For a start the typical BNC connectors that we commonly refer to as " 75 ohm" are strictly speaking not. Their correct specification is 50/75ohm. I only know of one true 75ohm connector which is made by Canare and if you see one you will quickly see that the dimensions needed to maintain the distance between conductor and dielectric to keep 75ohm throughout are not at all like the the connectors you will probably be familiar with. Further on most dCS designs the connection between the chassis receptacle and the PCB is via twisted hookup wire ( also not 75 ohm). Moreover although these specs may differ, in domestic audio you are normally not using lengthy wires between the boxes and characteristic impedance is not as significant as with a long cable as may be encountered in a studio.
However the fly in the ointment is that there is a 50 ohm coax connector (not BNC) and it could be that your Esoteric uses these. That will make sourcing wires outside of custom build difficult.
I reckon that it may work out fine in practice. However I am open to correction.
I don’t think you’re going to hurt anything by giving it a try with a spare BNC cable. Just be sure to configure the Esoteric Drive to receive a TTL clock input (not sine wave).
At such low frequencies as 44.1kHz, the impedance mismatch is not going to have a major impact on the signal shape I’d imagine, pretty sure it’s going to work without too much trouble.
Good luck 
It will work, but the clock signal is critically important so an impedance mismatch may cause some sonic issues. A lot of it is going to have to do with how the Esoteric implements its clock synchronization circuit.
This is not entirely correct. There are different specs for 50 Ohm and 75 Ohm BNC connectors with the difference being the geometry of the dielectric. Indeed the Canare connectors are one that follows the 75 Ohm spec, but there are many others as well.
Thanks for that.
I will try like that, but perhaps I should also try an adaptation with a cable. Some resistors inside one of the connectors, 43 Ohms serie and 91 Ohms to the ground on the 50 Ohms side.
Listening, I don’t know, but electrically speaking, it seems it will be correct.
On thing is sure, Rossini player is really very good…
I saw all these transformers, perhaps I will try one, but I also want to build a cable by myself as I said previously, with two bnc connectors, and try.
I allready have built some for the 75 Ohms connection, and they are very good, better than most tried before.
We can hear the difference.
Pete, I’ve noticed the Esoteric website specs saying BNC coaxial cables with 50ohm ‘or’ 75ohm can be used - ‘or’ to my perception meaning both can be used. I am currently auditioning an Esoteric K-05X (demo model) which is rated at 75ohms and using it as a transport (clocked synced) to my Bartok and it is sounding really good. Thing is, the new K-05xs upgrade player is 50ohm like the P-05x mentioned in this thread! As that is the player I was really looking towards I may just have hang and wait awhile.
Maybe DCS should be looking at producing a dedicated & more affordable transport for the Bartok!!
Well I am sure that dCS might say that if you wanted a Bartok with a transport then they have a product called Rossini Player which offers other advantages too!
Esoteric’s point that both ( meaning either) 50 ohm and 75 ohm cables can be used with their transports kind of goes along with my expectation. However Andrew does not agree and says that you must only use 75 ohm with the Bartok.
I remain unconvinced because if one troubles to read the spec. sheets for Neutrik ( one of the most prestigious connector manufacturers) until very recently they specified their BNC connectors as 50/75 ohm. Only recently have they respecified them as 75 ohm. However we are looking at impedance not resistance. The calculation of impedance involves a frequency component. BNC connectors are actually connectors for the video not audio world. Hence Neutrik’s measurements are in the GHz range . So they are 75ohm @ xGHz. The dCS clock output is in the KHz range so the impedance at that frequency range is unspecified/unknown, for the Neutrik connectors at least.
Further I have used dCS clocks since the Verona and am now on my third ( a Vivaldi). All sound quite different using the same cables into the same DAC. Using different cables with the same clock and DAC also provides a different result even where all cables/connectors are specified by the manufacturers to be 75 ohm. Are their specs to be relied upon? Without a test laboratory to verify one way or the other I remain sceptical ( especially as I know of more than one cable manufacture who use the same cable for both 75 and 110 ohm cables. At least one company uses a different colour sheathing for each to give the impression of variety).
So in practice it may or may not make a a difference and any difference may or may not be beneficial. Without a test laboratory I doubt that you can l know what you are really using from a technical view aside from the manufacturer’s assertion which , in many cases is unreliable. So, IMO suck it and see.
Hello,
I have found that :
https://www.audioaficionado.org/archive/index.php/t-31846.html
A bit long to read but very interesting.
As I read, I think if 50 Ohms and 75 Ohms are both ok for 10 mHz clock, it would be ok for Rossini clock too.
Anyway, I bought an Impedance Matching Pad 50/75ohm, BNC/BNC, HUBER+SUHNER (cost including shipping : 33€) because I wanted to try it too.
Gilles
