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Post by Deleted on Jan 22, 2013 23:12:08 GMT
Avinash My caution is coming from the fact that digital Audio doesn't play by the ground rules that the "experts" claim are set in stone. You can't really take anything for granted with digital audio, other than the better the power supplies the better it sounds. I can generate .wav files with identical check sums where one version appears to have quite a veil over it, another version where both LF and HF are improved, and yet another version where HF is exaggerated to the point of ultimately becoming fatigueing to listen to. Martin Colloms has already verified my reports in HiFi Critic Vol.6 No.1 and various HFC forum threads. Regards Alex P.S. Jim mentioned "a bit more snap in high tones" We need to make sure that this improvement is also evident at LF. Further listening by Jim may well reveal an improvement in that area too. Yes, I am aware of the formulas for inductive and capacitive reactance.
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Post by Deleted on Jan 23, 2013 10:13:05 GMT
I have since modified my main +5V JLH PSU to use 47 ohms in the 0 Volt return path. TBH, I found this to sound better than in the other PSU using 100 ohms. It had more low end warmth too. However, the main JLH PSU is supplied via the same powerboard that the PC itself uses, while the other JLH PSU uses the same powerboard as the HA and X-DAC V3 , although powered from the same powerpoint. At the suggestion of Erin from Melbourne, I remade the USB-A plug a the PC end, by disconnecting the black wire as well as the already disconnected red wire. I then fitted a 220 ohm metal film resistor across the + and - pins of the plug. This means that only the D+ and D- leads are now in use. I have a feeling that it MAY be slightly better than with the 47 ohm resistor, but I wouldn't put money on it. Either of these methods gives noticably improved rips over the previous best rips of a few days ago.There appears to be a small improvement in minor clicks from other running background programs such as open email when it does it's regular check for new mail. Alex
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Post by themystical on Jan 23, 2013 11:54:28 GMT
Fantastic result Alex. You have now achieved galvanic isolation of the earth conductor, something that even the proffs designing the iFi failed to achieve. You really can't have it better than that......
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Post by Deleted on Jan 23, 2013 12:04:23 GMT
Fantastic result Alex. You have now achieved galvanic isolation of the earth conductor, something that even the proffs designing the iFi failed to achieve. You really can't have it better than that...... However, it isn't a universal fix, and the difference between 47 ohms in the 0 volts lead and this method is very small indeed , at least in my system, and this method didn't work with Jim's DACiT, as he had already tried similar previously.Jim's DACiT worked flawlessly up to 57 ohms in the 0volts line. However , rips saved using either new method are clearly superior to my best rips from even a few days ago. Regards Alex
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Post by pet240 on Jan 23, 2013 12:41:14 GMT
G'day Sandyk,
I'm up in Brisbane, been lurking a little while, looking for more info on this power injector you guys keep referencing to, what exactly am I looking for? On the next GB for amanero and have a WaveIO as well, so quite interested in playing here.
Thanks,
Drew.
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Post by themystical on Jan 23, 2013 15:46:09 GMT
However, it isn't a universal fix, and the difference between 47 ohms in the 0 volts lead and this method is very small indeed , at least in my system, and this method didn't work with Jim's DACiT, as he had already tried similar previously.J Regards Alex Alex Looking at Jim's Blog on CA, he has some issues with earthing on his set-up. For this to work, the earth potentials at both the source and the DAC need to be the same. In the UK, Europe and Australia, this is achieved by the earth pin connection to the power socket of each socket. There are proper earth conductor interconnecting the sockets to make sure that the earths are at the same potential. My belief is that this will work in most instances in most parts of the world. The only exception I can think of is where an item is "double insulated" and doesn't have an earth connection where it might not work. Avinash
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Post by Deleted on Jan 23, 2013 16:48:54 GMT
oooh, this has moved on again! I came armed with more 10ohm resistors for my JLH 5v PSU and the bar has been raised to 47ohm. Tomorrow then pet240The thread that has the best info is this one.
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n0vtz
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Post by n0vtz on Jan 23, 2013 17:51:28 GMT
Guys; This is Jim from CA. Ended up at 57 ohms trailed by 100 uH choke. No failures. This combination is indistinguishable from the diode, at least to these ears, and with this system. PC>USB>Dacit>Emotiva XPA-5>Snell C/V's Resolving this ground issue (attenuation as opposed to isolation) gives a noticeable smoothness-silkiness. HF is enhanced nicely with no harshness, nor unbalance created with mids and lows. I would say that avinish is correct in his assesment of the effect of the added inductance. I'll get around to playing with a cap in parallel, unless one of you beat me to it. Thanks for your posts. Great info. here. Sincerely, Jim
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Post by themystical on Jan 23, 2013 19:54:16 GMT
Guys; This is Jim from CA. Ended up at 57 ohms trailed by 100 uH choke. No failures. This combination is indistinguishable from the diode, at least to these ears, and with this system. PC>USB>Dacit>Emotiva XPA-5>Snell C/V's Resolving this ground issue (attenuation as opposed to isolation) gives a noticeable smoothness-silkiness. HF is enhanced nicely with no harshness, nor unbalance created with mids and lows. I would say that avinish is correct in his assesment of the effect of the added inductance. I'll get around to playing with a cap in parallel, unless one of you beat me to it. Thanks for your posts. Great info. here. Sincerely, Jim Good to see you here Jim. Keep us posted on your parallel capacitor experiment. Make sure it is directional (electrolytic) and pointing the right way. Avinash
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Post by Deleted on Jan 23, 2013 20:49:11 GMT
However, it isn't a universal fix, and the difference between 47 ohms in the 0 volts lead and this method is very small indeed , at least in my system, and this method didn't work with Jim's DACiT, as he had already tried similar previously.J Regards Alex Alex Looking at Jim's Blog on CA, he has some issues with earthing on his set-up. For this to work, the earth potentials at both the source and the DAC need to be the same. In the UK, Europe and Australia, this is achieved by the earth pin connection to the power socket of each socket. There are proper earth conductor interconnecting the sockets to make sure that the earths are at the same potential. My belief is that this will work in most instances in most parts of the world. The only exception I can think of is where an item is "double insulated" and doesn't have an earth connection where it might not work. Avinash Avinash Jim has since vastly improved his earthing, which enabled him to measure the noise of the JLH down to much lower levels. He used Ham radio antenna earthing techniques to get the improvement. Alex
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Post by Deleted on Jan 23, 2013 21:01:26 GMT
Hi Jim As I am now getting results in my system where I only presently have a feeling that the 220 ohm resistor in the USB plug MAY be slightly better than the earlier 47 ohm earth lift method , I won't be going there. Due to the use of a JLH in line with my LG BR writer, I already have so much detail and a lower noise floor, that I sure don't need any more HF detail. Apparent increased HF detail can also be due to low level wideband noise.Even M.C. was fooled when he listened to one of my comparison .wav files at too low a level.Turning up the wick should show that however. Regards Alex
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n0vtz
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Post by n0vtz on Jan 24, 2013 4:18:55 GMT
Alex;Well as problems go, that's not a bad one for an audiophile, to much detail. After this last mod, increased buffering a bit with JRiver 18. Just received JPlay 5. Increased sampling and changed engine to JRiver as opposed to xtreme. Incredible balance of freq.. Complex classical sounds are a bit better delineated. As I've said the system has worked very well for awhile, but with this grounding problem resolved for the external ps' with JLH it is even better. Jim
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ronzo56
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Post by ronzo56 on Jan 24, 2013 4:43:56 GMT
Sorry to get off topic. You guys have left me behind. Could you Bottom line it, does this thing work as advertised in your opinion or is it wishful thinking? Thanks, I am looking for some help with my laptop. New DAC coming in the mail. Regards, Ron PS- Good thread.
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Post by Deleted on Jan 24, 2013 11:08:29 GMT
Hi Ron In theory it sounds quite good, but I notice that a few people appeared to have cable compatibioty issues. If I were you, I would get thoroughly used to your new DAC, decide if it has areas you feel needing improvement, then think about the other. Regards Alex
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Post by Deleted on Jan 24, 2013 11:11:35 GMT
Hi Jim I am pleased that you are getting so much more enjoyment from it with the help of a little DIY effort. Kind Regards Alex
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ronzo56
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Post by ronzo56 on Jan 24, 2013 15:31:26 GMT
Thanks as always Alex for helping me work through the maze of digital audio. Who ever thought back in the vinyl days that listening to a recording would get this complicated or involved. And I might add this fun too! Now as to the money............. Hope you have a good day, off to teach standing sounds waves in room. Ron
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Post by Deleted on Jan 25, 2013 2:56:51 GMT
Something for the DIY person to experiment with. This post also appears in Computer Audiophile. I have found that .wav files saved to a Corsair Voyager USB 2.0 memory stick sound noticably better after either of these modifications. In theory, the LED and Resistor version has the potential to sound a little cleaner sounding, although I didn't find much difference between methods.Both of these versions sound better than with just VBus disconnected at the PC end of the USB cable when used with an external Linear +5V supply. Erin,Jim and Avinash have worked with me in this research, and Erin suggested the Resistor and LED version. I was already investigating that earth loop area,as I already knew about the earth loop, but Avinash pushed me into going much faster! That version does not however work for Jim's DACiT, but the resistor in the power return lead does.. Without that resistor there is a potential earth loop. Regards Alex. P.S. Be warned that doing this to a USB-A plug is quite a fiddly job. IF you intend to reply in this thread simply to argue about the merits of these changes, please don't bother. It is posted to stimulate people findings these things out for themselves. YMMV.Not all ears and equipment are created equal.
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Post by Deleted on Jan 25, 2013 13:41:10 GMT
Alex,
Does it matter what LED is used and does it have IYO an audible preference over just the resistor.
Ta
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Post by Deleted on Jan 25, 2013 19:45:25 GMT
Hi Chris It doesn't give any improvement over the resistor alone. It's purely cosmetic. It's hard enough to fit the resistor and avoid it's leads shorting to the metal of the plug, let alone fit a LED in series as well.If you fit the LED you will need to decrease the value of the resistor to take into account the voltage drop across the LED which will be around the 2V area for many LEDs. Regards Alex
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Post by Deleted on Jan 27, 2013 12:31:49 GMT
I brought my main JLH USB isolator up to date using 47r in the 0v lines. I then reripped some recordings I had done before. Even without all the other enhancements that, say, Alex has (blue ray, vibration treatment etc) the difference was very audible and very pleasing. An amazingly tiny tweak that reaps big rewards.
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jonclancy
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Post by jonclancy on Jan 30, 2013 18:05:33 GMT
Ahaa....maybe a clue here? A loop breaker circuit? See Fig 4 and explanatory text in this link. sound.westhost.com/earthing.htmOkay it is not exactly the same, back to back diodes - not a bridge but sure looks like the thing. Question is a USB earth connection work if it had a say 10 Ohm resistor it? and surely the parallel capacitor would let HF noise through which is what we are trying to avoid? That is my thinking exactly . In this case, it doesn't sound like a good idea to have a parallel ceramic capacitor. Regards Alex P.S. For R.G. members, there should be 100 of Greg Erskine's latest dual JLH PCBs departing for the U.K. around Friday this week. Jon Clancy will be announcing details after he returns from Sydney. I don't know about the costing at the moment, but it will be very modest , due perhaps to a donation to charity component? That will be Jon's call. There is NO profit involved with the JLH PCBs, as is always the case. Greg Erskine is owed a great deal of thanks for the time and effort, as well as money he has put into various versions of these PCBs to get them available to RG members , as well as a few members from other forums. Yep - I have them and will start a thread very soon. Pricing WILL be modest and will cover the development costs and go towards further iterations. As these are Greg's boards, there is no charity element this time. Bear with me. Cheers Jon
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