Alexander Posted January 18, 2019 Share Posted January 18, 2019 What if any effects would a typical coax 75ohm based interconnect cable have on the device(s) in is connected ti? Not sure what if any impedance would exist on a shielded twisted pair equivalent. Quote Link to comment Share on other sites More sharing options...
wvu80 Posted January 18, 2019 Share Posted January 18, 2019 I have the SVS Sound Path interconnects, twisted pair construction. They have an impedance of 110 Ohms. Quote Conductor DCR: 77 mΩ/meter Shield DCR: 30 mΩ/meter Nominal Impedance: 110Ω Nominal Capacitance: 39 pF/meter @ 1kHz Rated Bandwidth: DC-5.0 MHz (3M cable) with ≤1.1 VSWR and ≥27dB Return Loss Resilient, cotton-braided jacket forms the 5th layer of the RFI Shield https://www.amazon.com/d/RCA-Cables/SVS-SoundPath-2M-RCA-Interconnect/B0197UUMD8/ref=sr_1_3?s=electronics&ie=UTF8&qid=1547814609&sr=1-3&keywords=svs+cables Check out the construction of this Monoprice RCA cable: https://www.monoprice.com/product?c_id=102&cp_id=10218&cs_id=1021810&p_id=18537&seq=1&format=2 +++ Your question was, what difference is there between 75 Ohm coax and twisted pair? Based on the above links, there is absolutely a difference in construction and impedance, but what qualitative difference is there in actual listening? I have no idea. Quote Link to comment Share on other sites More sharing options...
glens Posted January 18, 2019 Share Posted January 18, 2019 33 minutes ago, Alexander said: What if any effects would a typical coax 75ohm based interconnect cable have on the device(s) in is connected ti? Not sure what if any impedance would exist on a shielded twisted pair equivalent. Might have a look at wikipedia, I'm sure they'd have suitable information available. For audio frequencies, the Chinese-made stuff in blister packs at Walmart is entirely sufficient. Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 18, 2019 Share Posted January 18, 2019 6 minutes ago, glens said: For audio frequencies, the Chinese-made stuff in blister packs at Walmart is entirely sufficient. ooooh! Quote Link to comment Share on other sites More sharing options...
wvu80 Posted January 18, 2019 Share Posted January 18, 2019 12 minutes ago, glens said: For audio frequencies, the Chinese-made stuff in blister packs at Walmart is entirely sufficient. Agree, but the Walmart RCA cables are usually triple the price, or more compared to Monoprice coax. I'm thinking here of sub interconnects. For a 1 meter audio interconnect I would want something better than the Walmart cables. Quote Link to comment Share on other sites More sharing options...
glens Posted January 18, 2019 Share Posted January 18, 2019 I assumed moving-coil-to-preamp wasn't the consideration at hand. High level sub(woofer) interconnects? That's hardly even "audio" frequency! Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 18, 2019 Share Posted January 18, 2019 I'm still using the cheap cables that came with gear I bought in the early '70s. I've bought newer ones when I needed them but never anything exotic. 1 Quote Link to comment Share on other sites More sharing options...
Edgar Posted January 18, 2019 Share Posted January 18, 2019 A transmission line isn't a transmission line until it is at least 1/4 wavelength long. One-quarter wavelength at 20 kHz is 3.75 kilometers. As long as your interconnects are shorter than that, the concept of characteristic impedance doesn't apply. 2 Quote Link to comment Share on other sites More sharing options...
Alexander Posted January 18, 2019 Author Share Posted January 18, 2019 1 hour ago, wvu80 said: I have the SVS Sound Path interconnects, twisted pair construction. They have an impedance of 110 Ohms. Ah, the twisted pair is 110 ohms, probably insignificant difference between the two then. Just curious about that. Fully aware of the construction of both kinds of cable. 1 Quote Link to comment Share on other sites More sharing options...
The Dude Posted January 18, 2019 Share Posted January 18, 2019 2 hours ago, glens said: For audio frequencies, the Chinese-made stuff in blister packs at Walmart is entirely sufficient I may agree when it comes to carrying the signal, but not quality of craftsmanship or build quality. I have used the twisted pair of interconnects from Walmart, you can see green corrosion all the way through it, that and the fact that the connectors come loose, I would not spend the money. I have ran both RG59 and RG6 for interconnects with no issues. I have ran the Monoprice rg 59 with no issues. I mainly look for good shielded interconnects. 1 Quote Link to comment Share on other sites More sharing options...
TubeHiFiNut Posted January 18, 2019 Share Posted January 18, 2019 The only way you will know if the cables work in your system is to try them in your system and evaluate the sonic results with your own ears. I have listened to very expensive interconnects and speaker cables, cheap interconnects and speaker cables and everything in between. To my ears, in my preferred systems, I have found that the very reasonably priced Belden 8402 (shielded 2-conductor) with Switchcraft RCAs and Canare L5-CFB (75 ohm coaxial) with Canare RCAs interconnects and Dueland 12ga speaker wire work great with my SE amps and HE speakers based systems. All use tinned conductors. This combination has outperformed some very high priced stuff in my systems. It also sounds much more like music than the cheap generic stuff. This is just my opinion and YMMV. 2 Quote Link to comment Share on other sites More sharing options...
Deang Posted January 18, 2019 Share Posted January 18, 2019 2 hours ago, Edgar said: A transmission line isn't a transmission line until it is at least 1/4 wavelength long. One-quarter wavelength at 20 kHz is 3.75 kilometers. As long as your interconnects are shorter than that ... Lol. Funny. Quote Link to comment Share on other sites More sharing options...
wvu80 Posted January 18, 2019 Share Posted January 18, 2019 2 hours ago, Deang said: 4 hours ago, Edgar said: A transmission line isn't a transmission line until it is at least 1/4 wavelength long. One-quarter wavelength at 20 kHz is 3.75 kilometers. As long as your interconnects are shorter than that ... Lol. Funny. Shorter than two and a half miles? I didn't measure, but I'm reasonably sure my interconnects are shorter than that. I should be good to go. Quote Link to comment Share on other sites More sharing options...
Panelhead Posted January 18, 2019 Share Posted January 18, 2019 4 hours ago, Edgar said: A transmission line isn't a transmission line until it is at least 1/4 wavelength long. One-quarter wavelength at 20 kHz is 3.75 kilometers. As long as your interconnects are shorter than that, the concept of characteristic impedance doesn't apply. Double check the math. Quote Link to comment Share on other sites More sharing options...
wvu80 Posted January 18, 2019 Share Posted January 18, 2019 Paul McGowen, President of PS Audio released this just a few hours ago. Seems germane to the conversation, might add some food for thought. Quote Link to comment Share on other sites More sharing options...
Panelhead Posted January 18, 2019 Share Posted January 18, 2019 This is using a velocity constant of one. Most propagation coefficients range from 0.75 - 0.8. But still long. Quote Link to comment Share on other sites More sharing options...
Edgar Posted January 18, 2019 Share Posted January 18, 2019 21 minutes ago, Panelhead said: This is using a velocity constant of one. Most propagation coefficients range from 0.75 - 0.8. But still long. Yeah, I know. But I figured that the absurdity of several kilometers (miles) compared to a couple of meters (feet) was sufficient to make the point. Quote Link to comment Share on other sites More sharing options...
Edgar Posted January 18, 2019 Share Posted January 18, 2019 (edited) 1 hour ago, Panelhead said: Double check the math. Well, OK -- I used 3*10^8 meters per second for c; it's actually 299792458 meters per second. So 1/4 wavelength at 20 kHz is 3747.406725 meters. Assuming a worst-case velocity factor of 0.75, as suggested in a subsequent post, the quarter wavelength in the cable is 2810.554294 meters. Edited January 18, 2019 by Edgar Added missing word. Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 18, 2019 Share Posted January 18, 2019 Hmmm, I find a FULL wavelength of 20khz is only .17 inches. What am I missing here? Bruce Quote Link to comment Share on other sites More sharing options...
glens Posted January 18, 2019 Share Posted January 18, 2019 Radio (light) waves vs. audio (sound). 20kHz is a long radio wave. 1 Quote Link to comment Share on other sites More sharing options...
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