[mandrake50]

I think that this buzz/hum is a well known issue with this the SE output into <32ohms. It has been a huge annoyance for me. I own so many headphones that are under 32ohms and I can detect this hum with all of them even in lo gain.The HP's that I use that I can detect this sound with are the Focal Spirit Pro, B&O H6, Phiaton MS500, VModa M100, Cardas EM5813, and Noble Savant. With my 62ohm AKG K712&K702 Annies and MrSpeakers Alpha Dogs no hum detected. Oddly enough I get a completely black background with my 32ohm Grado RS1i. I have a thicker medical grade power cable powering the LC and the buzz does not change with the source being connected or not and becomes more apparent after the LC has warmed up. I get no hum from my Schiit Asgard 2 which cost me substantially less money. So I guess I will just be sure my next headphone will have to be balanced to compliment my Alpha Dog which I purchased specifically for the LC with a Bal. termination. If this hum/buzz issue is something that can be remedied by sending the LC back and paying a fee to correct or lower the amps overall gain; I would gladly do it instantly. CEntrance offered a factory modification on the HiFiM8 Dac/Amp that lowered the overall gain level but allowed for the amp section to be totally black with virtually any impedance. I'm thinking that I will just have to buy the Liquid Spark for my SE low impedance cans/iems and hope that it has a black background.

Are you getting the hum only when driving the LC balanced from your DAC using the SE out? I noticed that I never had any noise or hum when driving the LC SE. I never had any noise using the Balanced output regardless of the input configuration. Beyond that, when I leave the SE inputs connected to the DAC, but select the Balanced inputs, there is no noise on the SE output.
 
It seems that this is a grounding problem. I believe that the shield/ground connection for the balanced input is not connected to chassis ground. I thought that this could be a cable problem due to anodizing on the shell of the balanced cables that I was using. I got some cables that had shells that are not anodized, but this did not help.
 
A simple test would be to connect some patch cables from the SE out on your DAC to the SE in on the LC. From my experience this fixes the problem, even if only one RCA to RCA cable is connected.
Even simpler would be to just connect a wire from the shell of the RCA outs on the DAC to the shell of the RCA inputs on the LC. I think just touching the wire on both ends would tell you whether this is a fix. If so, a more permanent solution can be fashioned.
 
BTW, if you read back in the thread a bit, you will read that this solution has worked for several people. It would be much quicker than hoping for a hardware change that may never come.

 

[Dave74]

 
Are you getting the hum only when driving the LC balanced from your DAC using the SE out? I noticed that I never had any noise or hum when driving the LC SE. I never had any noise using the Balanced output regardless of the input configuration. Beyond that, when I leave the SE inputs connected to the DAC, but select the Balanced inputs, there is no noise on the SE output.
 
It seems that this is a grounding problem. I believe that the shield/ground connection for the balanced input is not connected to chassis ground. I thought that this could be a cable problem due to anodizing on the shell of the balanced cables that I was using. I got some cables that had shells that are not anodized, but this did not help.
 
A simple test would be to connect some patch cables from the SE out on your DAC to the SE in on the LC. From my experience this fixes the problem, even if only one RCA to RCA cable is connected.
Even simpler would be to just connect a wire from the shell of the RCA outs on the DAC to the shell of the RCA inputs on the LC. I think just touching the wire on both ends would tell you whether this is a fix. If so, a more permanent solution can be fashioned.
 
BTW, if you read back in the thread a bit, you will read that this solution has worked for several people. It would be much quicker than hoping for a hardware change that may never come.

I get the SE hum when using my Hugo RCA(SE) output to LC.  I have never tried a balanced source as I no longer have one. This now is making me wonder if it is due to the Hugo being battery powered (no path to ground) so it is creating a ground loop?  Unfortunately I no longer have a desktop DAC so I can't test this out.  
I do not have a hum with my Sustain84 amp though and that is strictly a SE amplifier also using the Hugo as a DAC.

 

[musiclvr]

Are you getting the hum only when driving the LC balanced from your DAC using the SE out? I noticed that I never had any noise or hum when driving the LC SE. I never had any noise using the Balanced output regardless of the input configuration. Beyond that, when I leave the SE inputs connected to the DAC, but select the Balanced inputs, there is no noise on the SE output.

It seems that this is a grounding problem. I believe that the shield/ground connection for the balanced input is not connected to chassis ground. I thought that this could be a cable problem due to anodizing on the shell of the balanced cables that I was using. I got some cables that had shells that are not anodized, but this did not help.

A simple test would be to connect some patch cables from the SE out on your DAC to the SE in on the LC. From my experience this fixes the problem, even if only one RCA to RCA cable is connected.
Even simpler would be to just connect a wire from the shell of the RCA outs on the DAC to the shell of the RCA inputs on the LC. I think just touching the wire on both ends would tell you whether this is a fix. If so, a more permanent solution can be fashioned.

BTW, if you read back in the thread a bit, you will read that this solution has worked for several people. It would be much quicker than hoping for a hardware change that may never come.

Oh okay, wow thank you mandrake50! I hadn't been aware of these simple solutions at all. My dac is not a fully balanced one so I will get to trying out your recommendations. When connecting the wire to the rca outs of both the LC and Dac should I connect a separate wire for the rca L and R?

 

[shultzee]

The only configuration I got a hum was balanced in and se out.  Very slight hum  with the volume turned low.   Balance in/out, and se in/out was dead silent for me even using a very sensitive IEM. 

 

[mandrake50]

Oh okay, wow thank you mandrake50! I hadn't been aware of these simple solutions at all. My dac is not a fully balanced one so I will get to trying out your recommendations. When connecting the wire to the rca outs of both the LC and Dac should I connect a separate wire for the rca L and R?

It is just a matter of getting the ground potential of the DAC and LC at the same level. It only takes one wire to do that. A simple wire with alligator clips on both ends clipped to the shell of the RCAs on both the DAC and LC  should work... if this is the problem.

 

[pippen99]

 
It is just a matter of getting the ground potential of the DAC and LC at the same level. It only takes one wire to do that. A simple wire with alligator clips on both ends clipped to the shell of the RCAs on both the DAC and LC  should work... if this is the problem.

I​ am using the RCA outs on my DAC to a second amplifier.  How can I solve this?

 

[mandrake50]

Oh okay, wow thank you mandrake50! I hadn't been aware of these simple solutions at all. My dac is not a fully balanced one so I will get to trying out your recommendations. When connecting the wire to the rca outs of both the LC and Dac should I connect a separate wire for the rca L and R?

One thing to know... you mention your DAC is not "FULLY" balanced. Does it have balanced outputs? Are you connecting to the LC balanced to balanced... and using SE out?
 
If you are using the SE out from your DAC to SE in on the LC... the thing I suggest may not help in the least. Specifically, in my experience, this worked when using Balanced OUT from the DAC to Balanced IN on the LC and using the SE OUT to power headphones or IEMs. If you are using SE OUT to SE IN... the grounds should be already bound together.

 

[mandrake50]

  I​ am using the RCA outs on my DAC to a second amplifier.  How can I solve this?

What "second Amplifier"?? My comments were only applicable to the Liquid Carbon. No way I can comment on other configurations without knowing much more.

 

[zachawry]

 
I get the SE hum when using my Hugo RCA(SE) output to LC.  I have never tried a balanced source as I no longer have one. This now is making me wonder if it is due to the Hugo being battery powered (no path to ground) so it is creating a ground loop?  Unfortunately I no longer have a desktop DAC so I can't test this out.  
I do not have a hum with my Sustain84 amp though and that is strictly a SE amplifier also using the Hugo as a DAC.

FYI, I used a Hugo RCA to LC no problem. 

 

[musiclvr]

One thing to know... you mention your DAC is not "FULLY" balanced. Does it have balanced outputs? Are you connecting to the LC balanced to balanced... and using SE out?

If you are using the SE out from your DAC to SE in on the LC... the thing I suggest may not help in the least. Specifically, in my experience, this worked when using Balanced OUT from the DAC to Balanced IN on the LC and using the SE OUT to power headphones or IEMs. If you are using SE OUT to SE IN... the grounds should be already bound together.

Ah darn it! Yeah I'm using the PeachTree Dac-iTx which is only SE. Back to the drawing board I guess.....

 

[pippen99]

 
What "second Amplifier"?? My comments were only applicable to the Liquid Carbon. No way I can comment on other configurations without knowing much more.

DAC Auralic Vega feeding Liquid Carbon via balanced XLR cables/ feeding Woo WA5 via RCA  cables.  When I unhook the WA5 and feed the LC via RCA the hum ceases.  I want to know how to ground the units safely keeping both amplifiers hooked up to the Vega.

 

[mandrake50]

  DAC Auralic Vega feeding Liquid Carbon via balanced XLR cables/ feeding Woo WA5 via RCA  cables.  When I unhook the WA5 and feed the LC via RCA the hum ceases.  I want to know how to ground the units safely keeping both amplifiers hooked up to the Vega.

With three devices, things become more complex. I would try clipping a wire from the Auralic to a chassis ground (RCA shell) on the LC. The hum has nothing to do with the Woo,,, just the difference in grounds between the Auralic and the LC. I bet, if you connect both the SE AND Balanced connections from the Auralic to  the LC... but select the Balanced inputs on the LC... but use SE OUT, there is no hum. I am not positive, but I think the WOO does not matter in this scenario. The DAC and LC have to be grounded together.
 
(EDIT):
If you just want to do a quick and dirty test, get a piece of insulated wire with ends stripped back a few MM. Listen in the configuration where you hear the hum. Touch one end to the ground (shell) of the RCA SE connector on the Auralic and the Other end to the same on either of the RCA SE inputs on the LC. If the um changes ...hopefully goes away, you know what you need to do. Figure out a more permanent connection and be happy. The complicating factor is only what happens to the WOO... but it is already bound to ground on the Auralic... if tying that to the LC works with the bare wire lets everything work fine, you are golden.  Give it a shot, I really can't see how you can hurt anything.

 

[pippen99]

 
With three devices, things become more complex. I would try clipping a wire from the Auralic to a chassis ground (RCA shell) on the LC. The hum has nothing to do with the Woo,,, just the difference in grounds between the Auralic and the LC. I bet, if you connect both the SE AND Balanced connections from the Auralic to  the LC... but select the Balanced inputs on the LC... but use SE OUT, there is no hum. I am not positive, but I think the WOO does not matter in this scenario. The DAC and LC have to be grounded together.

My concern is trying to create the ground with the WA5 connected to the Vega.  I already know the WA5 has nothing to do with the hum.  But if I do what you suggest I am creating a three way connection with all units.  Now this might be exciting in another context but is it wise in an electrical context?

 

[Dave74]

 
FYI, I used a Hugo RCA to LC no problem. 

Ok.  Thanks. I have been mostly using the balanced out anyways, and I have no issues with it.

 

[mandrake50]

Ah darn it! Yeah I'm using the PeachTree Dac-iTx which is only SE. Back to the drawing board I guess.....

Many times, if not most, low level 60 cycle hum is due to grounding problems. referred to as ground loops. Trying things like reversing the line plug, or using a cheater plug to lift ground from the third pin ground can be effective, depending on the situation. In car installations I have done, using ground isolation connectors or transformers to isolate power has been required. If using a power brick, sometime just changing to a different one can fix things. In any case, more than likely it is something peculiar to your installation that is the problem. The LC has had some issues, but from what Alex posted back a ways major issues that they have seen are not the things that create low level hum...