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Post by Deleted on May 23, 2013 11:59:14 GMT
When I touch the PSU's case I feel a slight buzz like it's not earthed properly. Of course, it isn't earthed in that the mains lead is a two-prong figure of 8 affair, and the 12V DC outputs are just that; +ve and -ve conductors.
I read some negative criticism of the V-PSU here (http://www.tech-diy.com/RegPowerSupplies/MusFidelity/MusicalFidelity_VPSUii.htm) and I quote "With no ground connection the chassis becomes one big capacitor pulling in radiated signals from the line, and radiating into the environment". Is this phenomenon related to the buzz I get when touching the case?
Should I run a ground lead form the V-PSU casing to, say, another item this is earthed? Sorry to show myself as ignorant on this.
Derek
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Post by Deleted on May 23, 2013 13:13:51 GMT
When I touch the PSU's case I feel a slight buzz like it's not earthed properly. Of course, it isn't earthed in that the mains lead is a two-prong figure of 8 affair, and the 12V DC outputs are just that; +ve and -ve conductors. I read some negative criticism of the V-PSU here (http://www.tech-diy.com/RegPowerSupplies/MusFidelity/MusicalFidelity_VPSUii.htm) and I quote "With no ground connection the chassis becomes one big capacitor pulling in radiated signals from the line, and radiating into the environment". Is this phenomenon related to the buzz I get when touching the case? Should I run a ground lead form the V-PSU casing to, say, another item this is earthed? Sorry to show myself as ignorant on this. Derek Hi Derek As I suspected before checking the link, it's another damn switchmode power supply. Most consumer SMPS have a capacitor between the high voltage primary side and the secondary (output) side. If you have a DMM you will most likely read up to 100VAC between the -VE side of the output and mains earth . This is causing the buzz that you feel when you rub the case. The explanation you quoted is BS. Their cases are not designed to be earthed, although you can get rid of the mains "tingle" by connecting the case via a 22nF 275VAC X2 type capacitor to mains earth using just the earth wire of a 3 prong mains plug , plugged into a mains socket. It MUST be the ONLY wire on the plug though. If you were competent with mains wiring, you could fit a 3 pin mains plug instead of the existing 2 wire, and connect the earth of the mains lead to case via that capacitor fitted internally. I don't recommend that unless you have expertise in that area !!!  The idea of using a capacitor in this manner was originally published in Silicon Chip magazine as a ": Tingle Terminator." Regards Alex |
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Post by Deleted on May 23, 2013 13:38:59 GMT
Thanks for the reply Alex - I too was surprised (disappointed?) to find that the V-PSU II was a switch mode power supply - but I can confirm that it does improve the V-DAC as, in deed, it is supposed to.
I would have no concerns about earthing the case via that capacitor as you describe - but is there anything against leaving things as they are? I'm happy to avoid touching the case!
D.
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Post by Deleted on May 23, 2013 21:34:27 GMT
Hi Derek
If it isn't used with anything such as an amplifier that is connected to mains earth, then the little bite that you will get when plugging in and unplugging the powered device will not bother you.
However, if you connect the DAC powered by SMPS to an amplifier, or via a preamplifier to the amplifier that is earthed, you will have reduced signal to noise ratio , possibly evident as a slight hum through speakers that is noticed when close to them.
Kind Regards
Alex
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Post by PinkFloyd on May 24, 2013 10:32:43 GMT
I didn't realise the V-PSU was switched mode |
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Post by Deleted on May 24, 2013 13:28:57 GMT
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Post by Deleted on Jun 23, 2013 11:04:33 GMT
Found this pic of the V-PSU 2 interior:  Very different from the V-PSU 1  |
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Post by PinkFloyd on Jun 23, 2013 19:36:30 GMT
Found this pic of the V-PSU 2 interior: Very different from the V-PSU 1 I'm sorry Derek, and I don't normally slate things, but BOTH of those look pretty shite.... add in the fact that they have THREE outputs..... I think I would rather run three bog standard wallwarts than power three "V" components from one of those. The V2 PSU is definitely switched mode. I would be happy to build you a Pinkie to try to see if you notice any difference between linear / regulated and switched mode..... it only has ONE output but I'd like to think that it is a quality output  Mike. |
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Post by Deleted on Jun 23, 2013 22:24:25 GMT
Hi Mike
I agree. Both appear to be different shades of mediocrity. Does the original even have voltage regulation ?
Kind Regards
Alex
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Post by PinkFloyd on Jun 24, 2013 0:43:35 GMT
Hi Mike I agree. Both appear to be different shades of mediocrity. Does the original even have voltage regulation ? Kind Regards Alex NO! I'm beginning to seriously doubt Musical Fidelity...... they used to be good but appear to be producing shite these days..... nice "enclosures" but the innards are pretty ugly / embarassing / at best, "mediocre"...... The original is NOT regulated, it's a pretty sad state of affairs  |
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