I am looking for help to solve a small amount of noise, consistant with HDD operation, mouse movements, etc... Heard at the speaker and enough to be annoying.
Set up is an Elekit Amp and Elekit Pre-amp, turntable and PC, with RCA out> into the Pre-amp. When listening to vinyl there is absolutey no noise, it's perfect. If I decide to listen from the PC (J-river/Flac), i.e. use a different input at the pre-amp, there is annoying humm as above. I have a power board that filters and everything is plugged into the same board from 1 AC outlet. I have tried a few of the ferrite chokes on the power cords to no avail. Pulled the PC apart and looking at the sound card, chassis, etc... I can see little screws that appear to earth everything as it should. Looked around on the forum and wouldn't know where to add a wire to stop a ground loop, if that is the issue, from occurring.
It is a recently built PC with a EV brand sound card.
My question possibly is, if the noise can't be solved, is it easier to purchase something that will use SPIF/Toslink (PC has this) in and RCA out (to the pre-amp), that doesn't reduce the sound quality, and get around the noise issue that way, or is there more I can do to solve to problem at it's source, i.e. in the PC.
I can add images of the PC internals, etc.. if that helps.
All help appreciated as I'm fairly new to the audio world.
James
Set up is an Elekit Amp and Elekit Pre-amp, turntable and PC, with RCA out> into the Pre-amp. When listening to vinyl there is absolutey no noise, it's perfect. If I decide to listen from the PC (J-river/Flac), i.e. use a different input at the pre-amp, there is annoying humm as above. I have a power board that filters and everything is plugged into the same board from 1 AC outlet. I have tried a few of the ferrite chokes on the power cords to no avail. Pulled the PC apart and looking at the sound card, chassis, etc... I can see little screws that appear to earth everything as it should. Looked around on the forum and wouldn't know where to add a wire to stop a ground loop, if that is the issue, from occurring.
It is a recently built PC with a EV brand sound card.
My question possibly is, if the noise can't be solved, is it easier to purchase something that will use SPIF/Toslink (PC has this) in and RCA out (to the pre-amp), that doesn't reduce the sound quality, and get around the noise issue that way, or is there more I can do to solve to problem at it's source, i.e. in the PC.
I can add images of the PC internals, etc.. if that helps.
All help appreciated as I'm fairly new to the audio world.
James
Is that a desktop PC or a laptop? It doesn't matter really as the problem is the same... the computer is generating noise that gets transferred to the audio system via the analog soundcard. Built-in soundcards are notoriously poor though so the solution to cure the noise and improve SQ is to use an external soundcard/interface perferrably with an optical link to the PC to isolate the ground... which is how the noise is transmitted.
It's a desktop PC.
In the absence of being able to cure the fault at the source, I would be open to suggestions on what to purchase and place between the PC and Pre-amp.
Something along the lines of a Cambridge Audio Dac Magic, etc...??? Would really appreciate feedback/experience on what's a good unit to go with if that's the solution.
James
In the absence of being able to cure the fault at the source, I would be open to suggestions on what to purchase and place between the PC and Pre-amp.
Something along the lines of a Cambridge Audio Dac Magic, etc...??? Would really appreciate feedback/experience on what's a good unit to go with if that's the solution.
James
On laptops It is solved by buying an aftermarket non-earthed two prong PSU.
This is what I did on my old Sony Vaio & Toshiba.
On desktops there is usually no noise if using a decent sound card. Motherboard soundcards are usually of mediocre quality.
My Desktop is now 8 years old and I don't know if newer motherboards sound chips are behaving better in this respect. My Logitech 5.1 speakers aren't grounded, but the hook-up to my 40 year old grounded Pioneer Cassette deck was working fine.
EV brand, do You mean Electrovoice ? Should work fine since it is a reputable brand.
Are both amp & pre-amp grounded ?
Try a simple wire grounding the amp, pre-amp & PC chassis.
Try also a ground lift at the amp or pre-amp.
Bear in mind, there are cables and cables. One time I've purchased a 3m cheap Philips labelled RCA cable and when hooked to my Sony AVR alone laying in the floor there was hum.
I cannibalized the cable and I believe it was fake because the shielding was very poor.
Try another cable, but not those flimsy super-market cheap ones.
It doesn't to be Gold or Silver, but good constructed.
Try a musicians / PA shop.
Those shops usually carry good parallel RCA cables.
Ferrite chokes don't filter hum, but can filter RF interference.
You can also try a ground loop breaker found on car audio shops, but I doubt the quality / fidelity.
Jensen quality transformers for example cost ~100 bucks each.
This is what I did on my old Sony Vaio & Toshiba.
On desktops there is usually no noise if using a decent sound card. Motherboard soundcards are usually of mediocre quality.
My Desktop is now 8 years old and I don't know if newer motherboards sound chips are behaving better in this respect. My Logitech 5.1 speakers aren't grounded, but the hook-up to my 40 year old grounded Pioneer Cassette deck was working fine.
EV brand, do You mean Electrovoice ? Should work fine since it is a reputable brand.
Are both amp & pre-amp grounded ?
Try a simple wire grounding the amp, pre-amp & PC chassis.
Try also a ground lift at the amp or pre-amp.
Bear in mind, there are cables and cables. One time I've purchased a 3m cheap Philips labelled RCA cable and when hooked to my Sony AVR alone laying in the floor there was hum.
I cannibalized the cable and I believe it was fake because the shielding was very poor.
Try another cable, but not those flimsy super-market cheap ones.
It doesn't to be Gold or Silver, but good constructed.
Try a musicians / PA shop.
Those shops usually carry good parallel RCA cables.
Ferrite chokes don't filter hum, but can filter RF interference.
You can also try a ground loop breaker found on car audio shops, but I doubt the quality / fidelity.
Jensen quality transformers for example cost ~100 bucks each.
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Use a meter, check the earthing from mains wire to chassis and SMPS on the PC.
Connect the PC chassis to amp chassis with a ground wire.
Check the SMPS, the cheaper ones omit the small ceramic filters on the primary and secondary sides, which act as high frequency snubbers. This could be the noise source.
Just see which ICs are used, you will find the circuits on line.
Also, if you live in a damp area, it may be the screws are rusted...put stainless screws with the threads coated with a little engine oil, it prevents rust.
Also, the wires themselves, some wires do not have shield continuity, remedy that.
Connect the PC chassis to amp chassis with a ground wire.
Check the SMPS, the cheaper ones omit the small ceramic filters on the primary and secondary sides, which act as high frequency snubbers. This could be the noise source.
Just see which ICs are used, you will find the circuits on line.
Also, if you live in a damp area, it may be the screws are rusted...put stainless screws with the threads coated with a little engine oil, it prevents rust.
Also, the wires themselves, some wires do not have shield continuity, remedy that.
IMO the cause of the PC noise is the very common ground loop, not a noisy soundcard or noisy power supply etc. The cause has been explained here and elsewhere many times. e.g. Solving Computer Audio Problems
Elekit Pre-amp Elekit TU-8500DX 12AU7 Pre-Amplifier Kit – diyAudio Store has no balanced inputs and uses class I isolation. IMO a decent preamp should either have (at least one set of) balanced inputs or be class II (its low power consumption allows an easier class II design than in power amps).
Also the EVGA soundcard for its price should offer balanced outputs because PCI(e) audio devices being used in class I desktop PCs are very likely to face noisy ground loops.
Elekit Pre-amp Elekit TU-8500DX 12AU7 Pre-Amplifier Kit – diyAudio Store has no balanced inputs and uses class I isolation. IMO a decent preamp should either have (at least one set of) balanced inputs or be class II (its low power consumption allows an easier class II design than in power amps).
Also the EVGA soundcard for its price should offer balanced outputs because PCI(e) audio devices being used in class I desktop PCs are very likely to face noisy ground loops.
Do you have a 50/60Hz hum in your speakers? If so, then it's a typical ground loop problem; otherwise the sound card itself is suspect, or you have a poorly filtered computer PSU that allows all kinds of noise on its 5V and 12V lines. I'd try transformer separation between the PC and preamp. And what phofman said about balanced inputs is true.
A ground loop will sound like 50/60Hz only if the psu is very clean, free of 100/120Hz and harmonics. Otherwise 50/60Hz will modulate the psu noise spreading noise through out the audio spectrum. This will make a ground loop sound like buzzing. Solutions already mentioned should work but if none is possible, then consider a ground lifter -or safety loop breaker. It worked well for me in a similar situation.
Thank you for the replies. After a lot of checking, disconnecting, re-routing/positioning components, etc... I was almost giving up and going to jut live with it, since it's not too bad... Then I realized that at different times of the day, the noise/buzz was more and less apparent. So, I lug a huge UPS (uninterruptible power supply) unit home from work to try and voila, cured. I only have the PC connected to it, everything else still connects to the one wall outlet? but for whatever reason I now have a dead silent background. I can't keep the UPS so will need to buy something that's hopefully not to many dollars to do the same job. Scratching my head as to why it's fixed and wonder why the UPS isolation was enough to make the PC quiet/cure the buzzes.
Change the SMPS, and check the motherboard and SMPS are properly earthed.
The PC might be getting energy on the earth from the wall outlet, check that too, Neutral to Earth you may have a leak.
You can connect the PC to another wall outlet using 3 core wire to check.
Then once you find the fault, get it fixed.
And see if your A/c is related to noise level, as it varies in the day, or whatever else is also working.
Check the wiring and earthing on that too.
The PC might be getting energy on the earth from the wall outlet, check that too, Neutral to Earth you may have a leak.
You can connect the PC to another wall outlet using 3 core wire to check.
Then once you find the fault, get it fixed.
And see if your A/c is related to noise level, as it varies in the day, or whatever else is also working.
Check the wiring and earthing on that too.
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IMO the UPS broke the ground loop somehow. The PC ground loop noise includes all ground return currents running through the MB in the section between the soundcard ground and the PSU ground terminal - hence all the HDD, GPU spikes, CPU spikes (= mouse, keyboard) noises.
Yes, I agree, but I have tried slot of things and if this fixes it I buy one thing to solve the problem and not, possibly, make a bad call and replace several things unnessesarily....
The fact that your big UPS breaks the loop does not necessarily mean another UPS will do so. If the ground pin on UPS output socket is hard-wired to the ground cable of the UPS input cable, the ground loop will not be broken.
Nelson Pass designed a nice filter for the V-Fet pt.1 amp (from 2021) yhat is located right after the on switching powersupply. , that eliminated all hum in my setup. I think it was Minidsps switching supply that was very noisy before. I use 112dB sensitive horns.
You needed to win a lottery, pt.1 or pt.2, but it is over now. Soon they will release V-FET-less kits at the DIY Audio store. There was some jealousy from the DIY pt.1 folks that wanted the even better filter (more capacitance) from the DIY V-fet pt.2 amp in their pt. 1 amp as well. So maybe there will be a release of just that power supply filter board, I don't know. But my pt.1 amp is completely silent, and every amp I have owned had massive hum in exactly the same spot.
Here's hoping because I would give it a go, meanwhile I might look around for some type of filter in the general electronic world, thankyou for the idea.
If you can hear HDD work noise, IMO a PSU filter on your amp will not help, unless it breaks the earth wire somehow.