USB DACs / Sound Cards and noise

Ophicleide

Member
Hi all,

I sometimes like to play music from my laptop (a Thinkpad X230) when it sits on my desk in a docking station. The docking station has a single 3.5mm output which I think duplicates the laptop’s 3.5mm headphone socket. For amplification and sound, I use two active studio monitors which I bought following some recommendations here, and also a passive-preamp which basically functions as a volume control knob and source selector. So the arrangement is basically: laptop 3.5mm -> 3.5mm to RCA splitter -> passive pre-amp -> active speakers.

The problem with this is that it is very noisy at higher volumes. I get a combination of a quite quiet low level hum; a high hum which is a bit noisier; and intermittant noise when (e.g.) I move the mouse.

I’ve tried using an external sound card which I had lying around (I think like this one) which improves the situation a bit but the noise is still present. This just has a micro USB input and various 3.5mm outputs so the data and power is carried by the same cable. The only thing that really seems to get rid of the noise is a ground loop isolator like this. However, I am not quite convinced that the isolator isn’t degrading the sound quality so was wondering if there are any other solutions.

I did wonder if there was a way to break the connection between the signal and the power but I couldn’t see any external sound cards or DACs which would take a USB data input but have a separate power supply. I therefore wonder whether that it not actually necessary and if I bought a more expensive sound card or DAC with a USB output then that would have sufficient protections within it to avoid noise? I also wondered whether I should use the cheap sound card’s TOSLINK output and then get a DAC which can convert TOSLINK to RCA or whether that would be mad and overkill?!

Can anyone point me in the right direction?

Many thanks!
 

larkone

Distinguished Member
Try a DAC with optical input - that will break the electrical connection and should sort the noise issue. Laptops/PCs are notoriously noisy so having something external can reduce this.
 

Ophicleide

Member
Try a DAC with optical input - that will break the electrical connection and should sort the noise issue. Laptops/PCs are notoriously noisy so having something external can reduce this.
Thanks. I’m glad that that might be an option. I just wonder if there are any others before I buy Yet-Another-DAC? I’d rather avoid continuing to bloat the number of boxes on my desk since I’d still need the external soundcard to generate the optical output.

Are there any all-in-one units which will air-gap the signal from the dodgy power?
 

oscroft

Member
Thanks. I’m glad that that might be an option. I just wonder if there are any others before I buy Yet-Another-DAC? I’d rather avoid continuing to bloat the number of boxes on my desk since I’d still need the external soundcard to generate the optical output.

Are there any all-in-one units which will air-gap the signal from the dodgy power?
If I understand correctly, you're only using analogue line-level (or headphone level) output so far? And you haven't tried a DAC-based digital connection yet? But you say you don't want to buy Yet-Another-DAC, so what if any DACs do you already have? I'm also not sure what kind of "all-in-one unit" you might be thinking of.

Computer analogue sound is notoriously poor - and some, as you've discovered, can be very noisy too. It does sound to me like you'd be much better off using a digital output. I use both optical output and (host powered) USB on a couple of different computers and both sound better than line out, though I don't suffer the noise problems you do and I don't need to break any USB power connection.

Anyway, tell us what (if any) DACs you've tried, and I'll offer the benefit of my limited knowledge and experience.
 
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dannnielll

Well-known Member
Thanks. I’m glad that that might be an option. I just wonder if there are any others before I buy Yet-Another-DAC? I’d rather avoid continuing to bloat the number of boxes on my desk since I’d still need the external soundcard to generate the optical output.

Are there any all-in-one units which will air-gap the signal from the dodgy power?
Hi. I have a little experience with this situation and have had a number of toys hanging around. Computers of a certain vintage already have optical outputs available on either a motherboard or a laptop 3.5 mm plug..there was a fashion once for these. So one of these into a optical input on a AVR and you are sorted.
I was using a USB connection from a laptop to the Coax input of the AVR using an external soundcard, and the hum was decidedly audible. It would only disappear when the laptop was on pure battery.the solution was to ensure it was from the same mains socket ,to reduce the earth loop or better ,use the optical..
There is very little difference between different external USB DACs soundwise. Even a cheap 10 euro Asus USB Zonar U3 is not greatly inferior to a Lindy DAC (reviewed on AVForums )Or a Maplin "Audiophile " or a Cyrus Soundkey( the best with headphones) ... However all are definitely superior to the Lenovo laptop ThinkPad chip
 

dannnielll

Well-known Member
Hi. I have a little experience with this situation and have had a number of toys hanging around. Computers of a certain vintage already have optical outputs available on either a motherboard or a laptop 3.5 mm plug..there was a fashion once for these. So one of these into a optical input on a AVR and you are sorted. There are also tiny usb to optical convertors.. They are not DACs so will not suffer any conversion losses.
I was using a USB connection from a laptop to the Coax input of the AVR using an external soundcard, and the hum was decidedly audible. It would only disappear when the laptop was on pure battery.the solution was to ensure it was from the same mains socket ,to reduce the earth loop or better ,use the optical..
There is very little difference between different external USB DACs soundwise. Even a cheap 10 euro Asus USB Zonar U3 is not greatly inferior to a Lindy DAC (reviewed on AVForums )Or a Maplin "Audiophile " or a Cyrus Soundkey( the best with headphones) ... However all are definitely superior to the Lenovo laptop ThinkPad chip
 

Ophicleide

Member
If I understand correctly, you're only using analogue line-level (or headphone level) output so far? And you haven't tried a DAC-based digital connection yet? But you say you don't want to buy Yet-Another-DAC, so what if any DACs do you already have? I'm also not sure what kind of "all-in-one unit" you might be thinking of.
Apologies. I may be being confused about the terminology.

At the moment, I have a USB external soundcard connected to the laptop. I am then using the line-level output from that via. the pre-amp to the speakers.

larkone suggested, I thought, that I should use a DAC with a optical input. The problem is my laptop does not have an optical output. I therefore assume the chain would go like this: Laptop -> USB cable -> External Soundcard -> TOSLINK cable -> DAC -> RCA cable -> pre-amp (etc.).

The reference to “one box” was to see if there was something which would interface with both the laptop and also produce the analogue output without relying on a single USB cable for both signal and power (since I’m pretty sure that’s where the problem arises).
 

Ophicleide

Member
Hi. I have a little experience with this situation and have had a number of toys hanging around. Computers of a certain vintage already have optical outputs available on either a motherboard or a laptop 3.5 mm plug..there was a fashion once for these. So one of these into a optical input on a AVR and you are sorted.
Yes: unfortunately, it doesn’t look like I’ve got one on this model and so the only way of getting audio out is via. USB. I’m a big fan of the 3.5mm analogue / TOSLINK port (not quite sure what the technical name is) and it’s a pity it’s not more widely used on consumer electronics.
 

jamieu

Active Member
On issue you might be hitting with those various components, that each can control volume, is gain structure.
 

Paul7777x

Distinguished Member
I’ve got the ifi version too. Uber quiet on my Mac.

I also use an old iPhone charger to power it.

(Do you mean the orange one?)
 

Numpty112233

Active Member
I’ve got the ifi version too. Uber quiet on my Mac.

I also use an old iPhone charger to power it.

(Do you mean the orange one?)
iFi iDefender3.0 External USB Ground Loop Eliminator - 'tis indeed orange
I power it direct from a USB outlet in the wall socket with a separate cable
 

Paul7777x

Distinguished Member
Hi all,

I sometimes like to play music from my laptop (a Thinkpad X230) when it sits on my desk in a docking station. The docking station has a single 3.5mm output which I think duplicates the laptop’s 3.5mm headphone socket. For amplification and sound, I use two active studio monitors which I bought following some recommendations here, and also a passive-preamp which basically functions as a volume control knob and source selector. So the arrangement is basically: laptop 3.5mm -> 3.5mm to RCA splitter -> passive pre-amp -> active speakers.

The problem with this is that it is very noisy at higher volumes. I get a combination of a quite quiet low level hum; a high hum which is a bit noisier; and intermittant noise when (e.g.) I move the mouse.

I’ve tried using an external sound card which I had lying around (I think like this one) which improves the situation a bit but the noise is still present. This just has a micro USB input and various 3.5mm outputs so the data and power is carried by the same cable. The only thing that really seems to get rid of the noise is a ground loop isolator like this. However, I am not quite convinced that the isolator isn’t degrading the sound quality so was wondering if there are any other solutions.

I did wonder if there was a way to break the connection between the signal and the power but I couldn’t see any external sound cards or DACs which would take a USB data input but have a separate power supply. I therefore wonder whether that it not actually necessary and if I bought a more expensive sound card or DAC with a USB output then that would have sufficient protections within it to avoid noise? I also wondered whether I should use the cheap sound card’s TOSLINK output and then get a DAC which can convert TOSLINK to RCA or whether that would be mad and overkill?!

Can anyone point me in the right direction?

Many thanks!

I’d suggest you just sell all you have and buy one of these.


Add a USB isolator if necessary, but it may not be with this one.
 

Paul7777x

Distinguished Member
iFi iDefender3.0 External USB Ground Loop Eliminator - 'tis indeed orange
I power it direct from a USB outlet in the wall socket with a separate cable

I’m surprised you’re still getting noise. With the ground cut and no power coming from your laptop, I’d expect it to be silent...

A curious one.

I used to use one of these too, but I couldn’t tell a difference. Though you might?


Having said that, I couldn’t swear there was any noise from the Mac in the first place. The orange thing is just insurance because USBs are allegedly always ‘dirty’.
 
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Ophicleide

Member
This will kill any ground loops you have with the laptop to usb input.

Thanks. That was the sort of product I was wondering about but couldn’t find. I wonder if the more expensive external sound cards / DACs which use USB for both data and power have one built in?

I’d suggest you just sell all you have and buy one of these.


Add a USB isolator if necessary, but it may not be with this one.
Thanks. That’s exactly what I was looking for in my first post: a DAC with a separate USB input and power supply. I’m afraid that wouldn’t be a replacement for everything since I’d still have to use the pre-amp to switch to other sources but it could be something I can add in. (I’m not convinced there is much market for a second-hand USB sound-card which cost £14 when new, but that’s by-the-by!)

A bit more searching for something that could replace the full lot, turned up this which looks like it has USB input; a separate power supply; volume control; and a selector to switch between USB and optical. I guess the volume control part of it wouldn’t be as good as the pre-amp I’m using from the photo of the board but whether that would make an appreciable difference, I don’t know.

I suppose the question is whether I try spending £20 on the USB isolator or go straight in with a more expensive replacement DAC. I appreciate these are small sums of money HiFi wise but I only use my laptop to play music sometimes and so I don’t want to spend an excessive amount!
 

Paul7777x

Distinguished Member
Yes. That one would do the job quite well.

I assumed you meant you required USB or optical. My bad.

However, if your usb output is very crappy, you may still need an isolator to break the earth connection.

Though there’s certainly no need to buy one until you try out the new dac\preamp.
 

Numpty112233

Active Member
Instead of USB out from Mac to DAC in amp would optical totally cure any ground loop hum?
What are the drawbacks of optical over USB (PCM & DSD rates etc) and is optical good sound quality for an 8 metre run?
 

Ophicleide

Member
I assumed you meant you required USB or optical. My bad.
No worries: it’s a bit of mess. When I am listening to music I usually use a chromecast audio (using its built in DAC so running 3.5mm to RCA). The laptop is mostly used for streaming videos and occasionally messing around with some softsynths. That’s the reason I can’t just stream to the chromecast: it’s too laggy for keeping in time with the screen / synth.

However, if your usb output is very crappy, you may still need an isolator to break the earth connection.
That thought is militating in favour of buying the isolator first since I think the cheap DAC in the external soundcard is “good enough” were it not for the noise.

Instead of USB out from Mac to DAC in amp would optical totally cure any ground loop hum?
What are the drawbacks of optical over USB (PCM & DSD rates etc) and is optical good sound quality for an 8 metre run?
I’m not sure I understand your first question since I can’t easily see how I can get any sound out of this laptop save by USB.

I’ve never used optical over long distances before, but isn’t it usually good for up to 10 metres or so with most modern equipment?
 

Numpty112233

Active Member
I’m not sure I understand your first question since I can’t easily see how I can get any sound out of this laptop save by USB.
Forgive me as I am in the dark as much as you and was asking as much for myself - but is optical out not an option via the headphone socket?
 

Ophicleide

Member
Forgive me as I am in the dark as much as you and was asking as much for myself - but is optical out not an option via the headphone socket?
I think only some laptops have it. It doesn’t look like Lenovo has ever used them from what I can see. Clearly it would have been a massive bonus for sound generally had they been standard for all 3.5mm jacks. I’d love one in my mobile phone (although I’m grateful it still has a 3.5mm jack!).
 

Paul7777x

Distinguished Member
Instead of USB out from Mac to DAC in amp would optical totally cure any ground loop hum?
What are the drawbacks of optical over USB (PCM & DSD rates etc) and is optical good sound quality for an 8 metre run?

DSD won’t transmit over optical at all, unless first down sampled to pcm as far as I recall.

As for 8mtres. No problem. I’ve used a cheap 20m optical cable between rooms before with no problems at all.

Except one. One usb to optical converter resolutely refused to work over that distance.

It may have been unable to ‘power’ it adequately, it was dirt cheap, about a fiver from eBay.

I used, over the years with that set up, at least half a dozen other optical outputs with no problems at all.
 
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Paul7777x

Distinguished Member
No worries: it’s a bit of mess. When I am listening to music I usually use a chromecast audio (using its built in DAC so running 3.5mm to RCA). The laptop is mostly used for streaming videos and occasionally messing around with some softsynths. That’s the reason I can’t just stream to the chromecast: it’s too laggy for keeping in time with the screen / synth.

That thought is militating in favour of buying the isolator first since I think the cheap DAC in the external soundcard is “good enough” were it not for the noise.

I’m not sure I understand your first question since I can’t easily see how I can get any sound out of this laptop save by USB.

I’ve never used optical over long distances before, but isn’t it usually good for up to 10 metres or so with most modern equipment?

If it’s just for occasional video and synth use then the sound card is certainly adequate.

And the CCA is very good indeed.

As I’m sure yo know, the isolator will only break the ground from the computer, you may still get some noise from the 5v supply from the computer.

I’m not a fan of passive preamps as they have no means of shielding themselves from any injected noise.
 

Paul7777x

Distinguished Member
No worries: it’s a bit of mess. When I am listening to music I usually use a chromecast audio (using its built in DAC so running 3.5mm to RCA). The laptop is mostly used for streaming videos and occasionally messing around with some softsynths. That’s the reason I can’t just stream to the chromecast: it’s too laggy for keeping in time with the screen / synth.

That thought is militating in favour of buying the isolator first since I think the cheap DAC in the external soundcard is “good enough” were it not for the noise.

I’m not sure I understand your first question since I can’t easily see how I can get any sound out of this laptop save by USB.

I’ve never used optical over long distances before, but isn’t it usually good for up to 10 metres or so with most modern equipment?

Ps, this would do the job for you, and allow you to retire the passive preamp. Good price too.

 

Ophicleide

Member
I’m not a fan of passive preamps as they have no means of shielding themselves from any injected noise.
On the other hand, it’s one less transformer to inject noise into the signal ;-)

Ps, this would do the job for you, and allow you to retire the passive preamp. Good price too.

Thanks. I’ve heard good things about Nobsound DACs but I’m pretty sure this is the same as the “Suca Audio DAC-Q5” which was on ebay for £20 less, using the usual metrics of “all of the same ports in all of the same places” that I use for Chinese audio stuff. It’s just a pity that I can’t see someone selling the boards without a case (even in AliExpress) since I bet about 50% of the price is on the latter...
 

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