nzlowie Posted September 15, 2017 Posted September 15, 2017 Hi all Just built this usb cable and recon it's a keeper! Easy to build so I thought I'd share and see if anyone else builds it and comes to the same conclusion. The cable is RG316 small RF cable I got from a phone and rt installer. No power just the data + & - and only earthed at the DAC end, pics tell the story. Give it a go and let me know what you think. Sent from my SM-T800 using Tapatalk 3
Batty Posted September 15, 2017 Posted September 15, 2017 (edited) I have some RG178 if anyone in Adelaide wants to try this. Edited September 15, 2017 by Batty 2
Upfront Posted September 15, 2017 Posted September 15, 2017 On 15/09/2017 at 7:52 AM, nzlowie said: Hi all Just built this usb cable and recon it's a keeper! Easy to build so I thought I'd share and see if anyone else builds it and comes to the same conclusion. The cable is RG316 small RF cable I got from a phone and rt installer.No power just the data + & - and only earthed at the DAC end, pics tell the story. Give it a go and let me know what you think. Sent from my SM-T800 using Tapatalk Out of interest, What was your last usb cable? 1
nzlowie Posted September 15, 2017 Author Posted September 15, 2017 On 15/09/2017 at 9:17 AM, Upfront said: Out of interest, What was your last usb cable? It replaced a chord silver plus. Not that hi up the food chain but that was still a big improvement on the generic cable I started with.Sent from my Moto G (4) using Tapatalk 1
Upfront Posted September 15, 2017 Posted September 15, 2017 On 15/09/2017 at 9:30 AM, nzlowie said: It replaced a chord silver plus. Not that hi up the food chain but that was still a big improvement on the generic cable I started with.Sent from my Moto G (4) using Tapatalk Still a 100 odd dollar cable and your happier with your 5 buck diy version. I like that! 1
Decky Posted September 16, 2017 Posted September 16, 2017 Sorry to ruin your fun and enthusiasm but you are using a standard 50ohm cable on a 90ohm expected impedance line. You might as well use a coat hanger. I built 3 various DIY USB cables with variable success and even with maintaining 90-100ohm impedance I would have transmission issues compared to the cheapest Chinese USB cable. Keep DIYing - maybe you will have better luck than me. 2
nzlowie Posted September 16, 2017 Author Posted September 16, 2017 On 16/09/2017 at 4:55 AM, Decky said: Sorry to ruin your fun and enthusiasm but you are using a standard 50ohm cable on a 90ohm expected impedance line. You might as well use a coat hanger. I built 3 various DIY USB cables with variable success and even with maintaining 90-100ohm impedance I would have transmission issues compared to the cheapest Chinese USB cable. Keep DIYing - maybe you will have better luck than me. Expand Decky, you're not ruining my fun or enthusiasm at all.... Made a cable that sounds better than my previous one , I'm happy. Don't really care about the impedance just know that after many changes back and forward between this and the chord cable I prefer this one. Maybe I could try a coat hanger next. Who knows, you might be onto something.
Alistair W Posted September 16, 2017 Posted September 16, 2017 On 16/09/2017 at 4:55 AM, Decky said: Sorry to ruin your fun and enthusiasm but you are using a standard 50ohm cable on a 90ohm expected impedance line. You might as well use a coat hanger. I built 3 various DIY USB cables with variable success and even with maintaining 90-100ohm impedance I would have transmission issues compared to the cheapest Chinese USB cable. Keep DIYing - maybe you will have better luck than me. Expand Hey Decky, Looks like nzlowie has wired it with each half of the differential pair going down a different length of coax. So what you have is two single-ended data lines, which should sum to 90 ohms. With 50 ohms coax, he's getting (50+50) = 100 ohms, so not far off. To be honest, you can get away with a fair bit so long as the cable isn't that long. Look inside some desktop PCs to see what I mean! Can't think why this would offer any sonic benefit over a twisted pair, you'd want the two lengths to be EXACTLY the same or you get skew between D+ and D- Anyway, love the DIY spirit nzlowie! Good on ya Cheers, Al.
nzlowie Posted September 16, 2017 Author Posted September 16, 2017 Cheers Al, that's exactly what I did . My theory is that each data stream is independent (shielded) from the other. As with a lot of diy.... No real facts to back it up but just give it a go and see what happens. Yes both lengths exactly the same. Everyone has given me lots of good advice so I thought I'd tell you about what has worked FOR ME, but I'd love for others to try this and see if they also find an improvement. Sent from my Moto G (4) using Tapatalk
davewantsmoore Posted September 19, 2017 Posted September 19, 2017 On 16/09/2017 at 9:12 AM, Alistair W said: Looks like nzlowie has wired it with each half of the differential pair going down a different length of coax. So what you have is two single-ended data lines, which should sum to 90 ohms. Expand No, it's the impedance of each pin which should be terminated to 90o.
Decky Posted September 19, 2017 Posted September 19, 2017 Some technical details from Wiki that might help: Type-A and -B pinout 1 VBUS Red or Orange +5 V 2 D− White or GoldData − 3 D+ GreenData + 4 GND Black or Blue Ground USB signals are transmitted using differential signaling on a twisted-pair data cable with 90 Ω ± 15% characteristic impedance. USB 3 uses tinned copper stranded AWG-28 cables with 90±7 Ω impedance for its high-speed differential pairs Low-speed (LS) and Full-speed (FS) modes use a single data pair, labelled D+ and D−, in half-duplex. Transmitted signal levels are 0.0–0.3 V for logical low, and 2.8–3.6 V for logical high level. The signal lines are not terminated. High-speed (HS) mode uses the same wire pair, but with different electrical conventions. Lower signal voltages of −10 to 10 mV for low and 360 to 440 mV for logical high level, and termination of 45 Ω to ground or 90 Ω differential to match the data cable impedance. SuperSpeed (SS) adds two additional pairs of shielded twisted wire (and new, mostly compatible expanded connectors). These are dedicated to full-duplex SuperSpeed operation. The half-duplex lines are still used for configuration. The D± signals used by low, full, and high speed are carried over a twisted pair (typically, unshielded) to reduce noise and crosstalk. SuperSpeed uses separate transmit and receive differential pairs, which additionally require shielding (typically, shielded twisted pair but twinax is also mentioned by the specification). Thus, to support SuperSpeed data transmission, cables contain twice as many wires and are thus larger in diameter.[83] The USB 1.1 standard specifies that a standard cable can have a maximum length of 3 metres (9 ft 10 in) with devices operating at full speed (12 Mbit/s), and a maximum length of 5 metres (16 ft 5 in) with devices operating at low speed (1.5 Mbit/s).[84][85] USB 2.0 provides for a maximum cable length of 5 metres (16 ft 5 in) for devices running at high speed (480 Mbit/s). The primary reason for this limit is the maximum allowed round-trip delay of about 1.5 μs. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost. When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns.[86] The USB 2.0 specification requires that cable delay be less than 5.2 ns per meter (1.6 ns/ft, 192000 km/s) - which is close to the maximum achievable transmission speed for standard copper wire). The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with AWG 26 wires the maximum practical length is 3 meters (9.8 ft). USB supplies bus power across VBUS and GND at a nominal voltage 5 V ± 5%, at supply, to power USB devices. Power is sourced solely from upstream devices or hosts, and is consumed solely by downstream devices. USB provides for various voltage drops and losses in providing bus power.
davewantsmoore Posted September 20, 2017 Posted September 20, 2017 On 19/09/2017 at 12:16 PM, davewantsmoore said: No, it's the impedance of each pin which should be terminated to 90o. Expand Doh
nzlowie Posted September 20, 2017 Author Posted September 20, 2017 So does all this mean my ears are wrong and the only way to get an improvement is to buy a $10k Audipquest cable?Sent from my Moto G (4) using Tapatalk
davewantsmoore Posted September 20, 2017 Posted September 20, 2017 Different, often sounds better - it's a preference / psychology thing. From an actual "has the performance really improved" (as opposed to whether you think it is has) .... there's waaay too many variables to generalise. It is possible that your cable is performing well, even better than your other one.
nzlowie Posted September 20, 2017 Author Posted September 20, 2017 From an actual "has the performance really improved" (as opposed to whether you think it is has) .... there's waaay too many variables to generalise.This is the thing about our hobby, impossible to quantify improvement, it is all about if we think it has.Be easy if it could be measured as easily as engine HP. We do the engine mods and tune for the torque and HP curves we want (where we want peak performance). Measurable, non of this "I think it's better". That's where I'm sure the psychology thing kicks in. I paid $$$$$$$ so it must sound better.!In my case I paid $2 and think it's better so I'm happy. In fact would have paid a lot more....Sent from my Moto G (4) using Tapatalk
niss_man Posted September 20, 2017 Posted September 20, 2017 I would hazard a guess that at least 50% of audiophile cables are produced by the listen by ear method (if not most) just like in this case. If it sounds better and is not causing you any dropouts in music then it works for your intended situation anyhow. If you do want to calculate impedance there are a few online calculators you can use but in this case, why bother it works already. Will be interested to find any other cable combos/methods that work well. Good work @nzlowie https://www.allaboutcircuits.com/tools/twisted-pair-impedance-calculator/ http://www.mantaro.com/resources/impedance-calculator.htm#twisted_pair_impedance
davewantsmoore Posted September 22, 2017 Posted September 22, 2017 On 20/09/2017 at 9:34 AM, nzlowie said: This is the thing about our hobby, impossible to quantify improvement Expand No, there's quite a number of ways the performance can be measured - which aren't too difficult / complex .... Just like a dyno and similar.
nzlowie Posted September 22, 2017 Author Posted September 22, 2017 I know we can measure distortion, Freq response so how do we measure"that sounds better"? We all like different kinds of sound signatures, some like SS some like tubes, some like box speaker some like electrostatic. Surely if it was as easy as reading a spec sheet that's all we'd need to do. All audio reviewers would be out of work!This is a lot like the old car argument, Ford's are better than Holden's. Both good cars with similar spec sheets yet devided buyers even though Ford's are better.Sent from my Moto G (4) using Tapatalk
davewantsmoore Posted September 22, 2017 Posted September 22, 2017 On 22/09/2017 at 7:56 AM, nzlowie said: how do we measure"that sounds better"? Expand Just like you can measure the performance of a car. Sometimes it will come down to personal preference ... or what is best for a specific purpose (especially when the purpose varied drastically - eg. tank vs gokart) .... but car boffins know an awful lot about car performance where it can be agreed that people generally like/dislike certain things.... you know like, more grip will increase my lap time ... and towing a caravan will do the opposite. There are a lot of things know about audio system performance where it's been shown that people will generally say "that sounds better" ... but like everything the world is complex, and different things can mask each other. What if I upgraded my engine, and tires ... and then towed a caravan. Better? Worse? a wash? who could say for sure? On 22/09/2017 at 7:56 AM, nzlowie said: some like SS some like tubes, some like box speaker some like electrostatic Expand I prefer to think of it as all of the above things have their tell-tale problems.... and some people are mored used to (or actually like) the sound of these problems. OTOH, all ""good" systems actually sound quite similar. On 22/09/2017 at 7:56 AM, nzlowie said: Both good cars with similar spec sheets yet devided buyers even though Ford's are better. Expand Sure, but as someone who knows cars well, you'd understand that the "spec sheets" for these machines don't usually actually provide much helpful detail on the performance. Audio systems are quit similar. The reason is that measuring, communicating, and interpreting enough information to actually understand the performance in a meaningful way is very hard. Yes, what someone prefers is going to have an enormous overriding influence on the "review" ..... but it isn't true that what "most people like/dislike" is beyond quantifying.
Kari80 Posted May 14, 2020 Posted May 14, 2020 Hi guys I have just built my cable using the the same RF cable. (RG316) This is a really good cable indeed. It didn't cost me a fortune so I thought to give it a go. I compared it with my friends cables and it was easily on the same level with a much more expensive cables. Thank you nzlowie. I am going to build some rca cables also a digital coax cable using the same rf cable. We will see...
nzlowie Posted May 14, 2020 Author Posted May 14, 2020 (edited) On 14/05/2020 at 1:07 PM, Kari80 said: It didn't cost me a fortune so I thought to give it a go. I compared it with my friends cables and it was easily on the same level with a much more expensive cables. Thank you nzlowie. Expand Good to hear someone else gave it a try, I'm still using mine. Couple of times I've gone back to Cord cable but always return to the DIY... Also tried this cable for interconnect but didn't really like them. Interested to hear how you get on. Edited May 14, 2020 by nzlowie
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