House de Kris
Loud-n-Deep
One more digital interconnect as supplied by DKak. This time a cable from PS Audio called the Digital X Stream. Nice name, wish I'd thought of that. This is a 1m cable with gold BNCs on each end. This is a thick, and relatively flexible, cable with a black netting over black that feels nice. Also included on the BNCs are custom PS Audio strain reliefs. This cable is pretty enough to deserve a picture. The cable was marked for direction, and I respected these markings for this test.
The TDR measures this cable as a 74.75ohm cable. Interestingly, there is a slight dip in the impedance curve at the connector. Even though it appears to be a 75ohm connector, the signal must pass through some section of the cable that is less than 50ohms (according to the TDR). Unscrewing the strain relief, it is evident that the structure of the cable wasn't maintained all the way into the connector, and they've got almost an inch of uncontrolled environment. Since I'm discussing this connector I may as well add that this is the poorest fitting BNC I've ever encountered. The outer locking mechanism would always bind when I tried to use it and had a bit of wobble. Other than that, 4.3ns for a 1m cable is a bit long if we look at other cables. Usually this would indicate a solid teflon dielectric instead of foam teflon, but as mentioned above, this is a pretty flexible cable which would suggest that it is not a solid dielectric. All of this is speculation, I don't know the exact dielectric.
The network analyzer found the frequency response of this cable to drop increadibly fast when compared to other BNC/BNC terminated cables in this test batch. The -1dB, -3dB, and -10dB points are 200MHz, 794MHz, and 2.29GHz respectively. This cable appears to measure as poorly as cables I've measured with RCA connectors. I believe the limited bandwidth is a product of the method of attaching the fat cable to the connectors.
The TDR measures this cable as a 74.75ohm cable. Interestingly, there is a slight dip in the impedance curve at the connector. Even though it appears to be a 75ohm connector, the signal must pass through some section of the cable that is less than 50ohms (according to the TDR). Unscrewing the strain relief, it is evident that the structure of the cable wasn't maintained all the way into the connector, and they've got almost an inch of uncontrolled environment. Since I'm discussing this connector I may as well add that this is the poorest fitting BNC I've ever encountered. The outer locking mechanism would always bind when I tried to use it and had a bit of wobble. Other than that, 4.3ns for a 1m cable is a bit long if we look at other cables. Usually this would indicate a solid teflon dielectric instead of foam teflon, but as mentioned above, this is a pretty flexible cable which would suggest that it is not a solid dielectric. All of this is speculation, I don't know the exact dielectric.
The network analyzer found the frequency response of this cable to drop increadibly fast when compared to other BNC/BNC terminated cables in this test batch. The -1dB, -3dB, and -10dB points are 200MHz, 794MHz, and 2.29GHz respectively. This cable appears to measure as poorly as cables I've measured with RCA connectors. I believe the limited bandwidth is a product of the method of attaching the fat cable to the connectors.