Avoid these universal PSUs. A noise and regulation of a dynamic load may be optimised for one voltage, not another. Or a poorly optimised in general to obtain a wide voltage range (depends on the make).
Rather get a fixed voltage industrial type in metal enclosure. Screw terminals give a good contact. A good brand with long reputation and reasonable pricing is Meanwell, but these days they are others not so bad.
I checked all the voltage options, none of them sound like having less buzz. I bought this and not an industrial psu for the ease of use, not whantign to make acase for it, i guess i shouldnt have bought that cheap Chinese psu anyway though.
It's not about the PSU being cheap, you would get the same buzz with any earthed PSU. You may want to look at isolation class II PSUs - no PE wire.
I have very good experience with Fujitsu Siemens adapters for Futro thin clients but they fetch only 20V/2-3 amps. There are certainly other options available.
I have very good experience with Fujitsu Siemens adapters for Futro thin clients but they fetch only 20V/2-3 amps. There are certainly other options available.
Hi Kyrk,
The power supply you use for the amplifier is clearly an SMPS. It is what is often referred to on this forum as “a brick”.
I will now list some possibilities that may cut your annoying ground-loop:
* Replace the PC with a laptop. PC supplies have several output voltages that raise and fall in a certain order. PC supplies can only with difficulty be replaced. Laptop supplies can easily be replaced because they have only a single voltage and less power than a PC supply. Operating on battery, a laptop is ideal because it is “floating” potential wise and without connection to the net it does not form part of a ground loop.
* Replace the amplifier SMPS with a power supply using a traditional transformer. I had myself ground-loops at occasions and normally I eliminated the problem by having only one SMPS in a signal path with more power supplies. With only one SMPS, I have only one safety capacitor connecting the signal path to the primary side. The transformer should have a 15Vac secondary.
* Use a power isolation transformer before the amplifier SMPS. Isolation transformers have the same output voltage as input voltage. They serve to isolate a secondary circuit from the dangerous network side. Today, isolation transformers are not so common.
* Insert signal transformers in-between the PC output and the amplifier input. Signal transformers have galvanic isolation between primary and secondary and thereby break the ground-loop. Signal transformers need not be very expensive but they need a drive circuit. Perhaps the headphone output from the PC is sufficiently low impedance to drive the signal transformers directly, perhaps not.
* Use an optical TOSLINK connection between the PC and the amplifier input. It requires that the PC has a TOSLINK output and you will need a DAC with TOSLINK input before the amplifier input. A TOSLINK connection has no quality loss and, with a good DAC, the quality can be better than the analog signal you get from many PC soundcards.
* Use a Bluetooth connection (radio link) between the PC and amplifier. I substantially use that because it is a very convenient solution. You put a DAC with integrated Bluetooth receiver in front of the amplifier input. If your PC has not already Bluetooth build in, you add a Bluetooth stick to an USB port. You can also use your SmartPhone as source as it has integrated Bluetooth. The slight disadvantage of a Bluetooth link is that it may be disturbed for short moments by other radio signals. Further, a Bluetooth link will reduce sound quality a little. Even the “lossless” standard (from version 4.0 of the Bluetooth standard) should use some kind of compression and thereby result in a slight loss in SQ. Bluetooth receivers are pretty cheap.
Kyrk, please study the above options. Unfortunately I do not know a solution to your ground-loop problem that is trivial to implement. When I know your preference, we can discuss the details of that solution.
Well, I cant use a laptop I want this system as my computer's 2.1 system
where can i find a psu with a regular transformer, how do i search for one and do you have a decent but fairly cheap one to recommend?
I am not sure what a signal transformer is and how it differs from a normal transformer, with a quick check i could not find something like that in my country, i did find some in ebay though. How is one wired exactly?
Unfortunately my motherboard doesn't have a toslink output, for this option i think i will need a soundcard with toslink out and an external dac. this solution sound like the most elegant but i think we are looking at 150euro minum cost. And i cant do that.
A bluetooth dongle was the first thing that came to my mind, but it sounds junky and unreliable, not to mention the quality loss. I think this is going to be my last resort or a temporary solution till i figure out one of the other ways.
Chould you please answer my above questions just to be sure what the options are.
Moreover a conventional dac that is connected to the pc with a usb connection cant be used? Also, why my conventional 2,1 system has no similar problem? Probably because it doesn't use a smps?
Lastly will a better 2.1 amp solve my problem? Like the:
Dayton Audio DTA-2.1BT2 100W 2.1 Class D Bluetooth Amplifier with Sub Frequency Adjustment
i was thinking of buying it, but i can see that it also uses a smps.
I dont understand. This is such an easy problem to occur, sounds like everyone in this forum should get that problem since these amps are more likely to be used with a computer. Would a better pc psu yield better results?I guess this is hard for you to say.
Thanks for your time FauxFrench
Are this IECs? I dont knwo how they look like or what i am supposed to search to find one. Are these the "traditional transformer" power supplies FauxFrench talked about?
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Just for a test, if you have VDE type power connections, you can put two small pieces of insulation tape over the two earth contacts visible in your wall 230V source and then carefully insert the SMPS plug. So you disable grounding. If buzz stop´s, you verified the problem.
Then we can find a solution. Maybe show a picture of you speakers, this way we can better decide which kind of quality losses may be acceptable.
I guess you overestimate the quality losses of some solutions.
Then we can find a solution. Maybe show a picture of you speakers, this way we can better decide which kind of quality losses may be acceptable.
I guess you overestimate the quality losses of some solutions.
I just isolated the earth. The buzzing is gone, just some normal hissing.
I just build my speakers they are a pair of Dayton Audio PS95 along with a GRS 8sw4 sub that I am. Currently building
GRS 8SW-4 8" Poly Cone Subwoofer 4 Ohm
Dayton Audio PS95-8 3-1/2" Point Source Full Range Driver 8 Ohm
I guess they are not exactly what you would call "hifi audio", so the Bluetooth option won't really hurt the quality. But I still found it a little junky.
I found some products that might help.
Would a ferrite choke on the 3.5mm cable do anything?
There are some "ground loop isolators" adapters in the market do these contain a signal transformer? Are they worth it?
Lastly I can only found a 21v 2 A power supply, that's labeled as a battery charger. Is this a normal type transformer power supply? They are fairly cheap but they will give less that 40watts won't they? Then again, for my current speaker setup this might be sufficient but I would like the headroom.
Attachments
Again - just use a PSU designed to work without the protection earth wire, which will not create the ground loop. Like FUJITSU SIEMENS ADP-60MB 19V -3.16A 65W Power Supply PSU CHARGER ADAPTER | eBay or AC ADAPTER For SONY Vaio PCG-FR100 GRS GRX PCG-NV VGN-FS VGP-AC19V26 19.5V 92W | eBay
OK, so you have a simple mains ground problem. You want to use the output of a sound card to sent an analog signal to your DSP /amp combination, basically by a cinch connection.
There are simple boxes to break up a ground loop. One use is car audio, the other PA stuff. As I don´t know your lokation, I can not point you to any offer. 20 Euros should be enough to buy such a device. A headphone sound card out is powerfull enough to drive such an audio transformer. Frequency response usually is 10-20.000 Hz, more than your combination will be able to produce.
Another way would be to get a cheap external sound card with an optical out. Around 10-20 Euros and a simple, low cost DAC, in the same price region.
Again, I can not point you to any ebay/ Amazon offer. The prices I mention are to the country with the funny flag that someone put on my account.
Maybe cheapest option, beside from the terrible sinn of an insulation of the mains ground, would be a "two mains pin only SMPS", as you get it with many computer stuff like printers or laptop chargers. There are a handfull of these in any house, as they last much longer than the gadget they powered.
There are simple boxes to break up a ground loop. One use is car audio, the other PA stuff. As I don´t know your lokation, I can not point you to any offer. 20 Euros should be enough to buy such a device. A headphone sound card out is powerfull enough to drive such an audio transformer. Frequency response usually is 10-20.000 Hz, more than your combination will be able to produce.
Another way would be to get a cheap external sound card with an optical out. Around 10-20 Euros and a simple, low cost DAC, in the same price region.
Again, I can not point you to any ebay/ Amazon offer. The prices I mention are to the country with the funny flag that someone put on my account.
Maybe cheapest option, beside from the terrible sinn of an insulation of the mains ground, would be a "two mains pin only SMPS", as you get it with many computer stuff like printers or laptop chargers. There are a handfull of these in any house, as they last much longer than the gadget they powered.
Well, I live in Greece. Any recommendations from European eBay sellers would be ok. I wan to avoid Chinese stuff mostly because i am board of waiting 1-2 months to use my speakers.
You mentioned a DSP/amp combination, does my amp has a dsp? I guess since it has a Bluetooth module it needs a dsp? I can see some usb contacts under the Bluetooth antenna, are they an input?
Those simple boxes that are used to break the gound loop contain a signal transformer that was previously mentioned?Do i really need a sound card to use one of this?Why cant i use my motherboard's output? Is this one of them?
https://www.amazon.de/AUKEY-Entstör...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
I can get one for 20 euros.Do i really need a sound card to use one of this?Why cant i use my motherboard's output? It uses a Realtech ALC892 that has 200ohm ouput impedance on the non-amplified signal.
https://www.hardwaresecrets.com/datasheets/ALC892-CG_DataSheet_1.3.pdf
Would buying a sound card with optical out and a dac a better solution? Why not just buy a dac that has usb input? So that i can skip the sound card?
You speak a little bit degrading of those 2pin smps. Why are they not considered a good idea?
Sorry, got you wrong, you use a 2.1 amp, no DSP.
Your "mother board output" is the output of an integrated sound card. These output´s usually have enough power to drive a headphone, which makes them capable of driving such an audio transformer. Try with some ear plugs!
Very high output impedance may not work with such a passive, galvanic separation device. You can get them active, too, but they might be more expensive, need power supply etc.
Yes, an USB - DAC may work too, if it does not ground the signal at both sides (=your problem!)
No, the two pin SMPS is just fine.
I try to show you options that at first work and second are not expensive, so you can pick what suits your situation best.
There may be other solutions, but the ones I mentioned are the most simple ones.
"May be solutions" would look like getting the SMPS very close to your PC and connect or separate ground lines, measure ground voltages or else, but these have to be done in you installation and are basically experimenting.
Your "mother board output" is the output of an integrated sound card. These output´s usually have enough power to drive a headphone, which makes them capable of driving such an audio transformer. Try with some ear plugs!
Very high output impedance may not work with such a passive, galvanic separation device. You can get them active, too, but they might be more expensive, need power supply etc.
Yes, an USB - DAC may work too, if it does not ground the signal at both sides (=your problem!)
No, the two pin SMPS is just fine.
I try to show you options that at first work and second are not expensive, so you can pick what suits your situation best.
There may be other solutions, but the ones I mentioned are the most simple ones.
"May be solutions" would look like getting the SMPS very close to your PC and connect or separate ground lines, measure ground voltages or else, but these have to be done in you installation and are basically experimenting.
An active isolator. Is the 200ohm considered high? I have tried with 48ohm headphones they worked pretty good, couldn't get extremely loud but it was loud enough. I thought that you would want to lair high impedance output with low impedance input because you might "short" the output circuit. Could you recommend a budget USB DAC?
A 200 Ohm line out is "strong" enough to drive the coil of a transformer. You shold always have low qutput and higher input impedance, this will work. If output impedance is to high or input to low, you use a buffer. Nothing special with your case, just basic audio fact´s.
This is a cheap external sound card I use for measuring audio. It has a very low noise floor and a very good frequency response. It has anything you may need, like optical out.
CSL USB 7.1 Soundkarte extern / 8-Kanal USB Soundbox inkl. Treiber-CD
DAC:
MINI DAC - DIGITAL ANALOG WANDLER - DA AUDIO CONVERTER - TOSLINK | eBay
Ground loop insulator:
DYNAVOX Massetrennfilter GLI 2.1 / Stereo-Line-Isolator / HIFI / PRO / KFZ / PC | eBay
This is a cheap external sound card I use for measuring audio. It has a very low noise floor and a very good frequency response. It has anything you may need, like optical out.
CSL USB 7.1 Soundkarte extern / 8-Kanal USB Soundbox inkl. Treiber-CD
DAC:
MINI DAC - DIGITAL ANALOG WANDLER - DA AUDIO CONVERTER - TOSLINK | eBay
Ground loop insulator:
DYNAVOX Massetrennfilter GLI 2.1 / Stereo-Line-Isolator / HIFI / PRO / KFZ / PC | eBay
If in the future, you plan and are a little bit patient, most articles from China cost less, often not even a fraction, because of the low price for P&P. Many of the stuff I order is cheaper than postage in Germany to Germany.
10 days is my usual wait for such an order, sometimes longer, sometimes only a week and very often Chinese sellers do not sent anything, until you complain. You get used to it.
If you are honest, nothing you (we) write about is really urgent. So please check how your country handles China mail, maybe like in Germany (up to 25 Euro inc. P&P are tax free if sent by mail, not Express or Courier service).
Might save you a small fortune.
10 days is my usual wait for such an order, sometimes longer, sometimes only a week and very often Chinese sellers do not sent anything, until you complain. You get used to it.
If you are honest, nothing you (we) write about is really urgent. So please check how your country handles China mail, maybe like in Germany (up to 25 Euro inc. P&P are tax free if sent by mail, not Express or Courier service).
Might save you a small fortune.
Sorry for offtopic - I order a lot from China (ebay, aliexpress) and in my experience I have to urge a very small fraction of the orders (likely < 5%). If there was a problem, I have always received full refund. No need to be afraid of ordering from China from the delivery POW. Quality is a different question, as always a function of price...
The shipping is free for small items. For larger items it is comparable to EU charges (often the S/H is already included in the price of an item with free shipping).
Nevertheless for a power adapter I would get a good brand used one, which will last safe for decades. Will cost the same as a cheap brand-new Chinese adapter but Chinese SMPSes tend to fail early due to low quality caps. An HP/Toshiba/FS/Asus pre-owned adapter will last. The class II ones are for older gear as newer notebooks almost always come with class I adapters (cheaper to produce safe).
I order in the far east for years now and have something from China in the letterbox, almost every day. The rate where items don´t show up at all, where cheaper or completely different items are sent (to get a "Delivered" reciept) and items that are DOA or fail in the first hours is more than 10%. A while ago this was much better, today they sent the quality to bad for the homeland to us.
Compared to the price, this is still perfectly OK. In 9 of 10 cases you get a refund for junk sent. Have a look at the sellers reputation, if he has only 95% satisfaction, he probably is not the best one to buy from... 98% is OK.
Compared to the price, this is still perfectly OK. In 9 of 10 cases you get a refund for junk sent. Have a look at the sellers reputation, if he has only 95% satisfaction, he probably is not the best one to buy from... 98% is OK.
Thanks for your recommendations and your time. The problem with all the other dacs is that they need an optical toshlink input that my Computer can't provide, adding an internal sound card to the equation. The external sound card with USB input would solve 5his but I can only find it at around 40 euros. I don't know I'd it's worth it at this price. The other cheap usb options seem way pretty bad. I am referring to those usb stick like sound cards. My preference would be a ground loop insulator but I am a little sceptical. I read online that it can muffle the low frequencies and that it reverses the signal phase. Is this true in your experience?
I ve purchased a lot of things from China mnevwr had to lay customs for cheap orders. But I am hearing, that the shipping times recently have increased because of the situation the country is in. Especially stuff that comes from Hong Kong.
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