Digital Drive Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Digital Drive ]

---

[ Alert Moderator ]

---

RE: Impedance question

Posted by knewton (A) on October 30, 2015 at 18:15:15

In Reply to: Impedance question posted by thom70 on October 30, 2015 at 15:59:28:

The controlling factor here is the characteristic impedance of the interconnect cable, which commonly are 75 or 50 ohms. The problem with RCA connectors in impedance matched applications is their low characteristic impedance, circa 30 ohms. BNC connectors are a better choice because their impedance can be made to match the 75 or 50 ohms of the cable. Connector impedance is a function of the connector's geometry and dimensions. RCAs simply don't permit the basic dimensions needed to provide a true 75 ohm impedance. With all of that in mind you can see why BNCs at both ends provides the better end-to-end impedance match with 75 ohm cable, while RCAs at both ends provides the worst.

Now, to your question about an mixed connector interface. In my view, it's better to have the RCA at the transport end with the BNC at the DAC end. This is because the signal reflection due to an impedance discontinuity is less likely to cause damage the nearer that discontinuity is to the source end - although, this is also a periodic function based on the length of the cable, and a function of the signal's rise time. Having an RCA at the source end and an BNC at the DAC end will still provoke less reflection than would having RCAs at both ends.

_
Ken Newton

Edits: 10/30/15 10/30/15 10/30/15 10/30/15 10/30/15 10/30/15 10/30/15

This post is made possible by the generous support of people like you and our sponsors:

The Cable Cooker

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---