[joseph69]

No, the power supply and amp are not steacked, as a matter of fact as far apart as the umbilical cord allows! Thanks, for the tip with the Mu-Metal. I've seen this posted in one of your earlier posts. Great idea. I need to find a supplier for Mu-Metal here in Europe, though.

Thought you might have had them stacked like me. Maybe something else is interfering with the PSU causing the hum? In any case, good luck with the issue.

I dunno, low gain in itself should be blk, I stack and I’m blk in med gain. Methinks it’s somewhere else

Before I bought the Mu-Metal I had a slight hum on MED gain when I initially switched over to it, but then it would slowly fade away. After using the Mu-Metal, as I mentioned, the amp is dead silent at all times on any gain.

 

[biosailor]

I had a similar problem when I first got my GS-X MK2 I resolved it by plugging Dac & amp into separate power circuits, no more unwanted noise. Hope this helps...

I tried it, but it didn't help. Thanks for the suggestion anyway!

 

[thyname]

Anyone experimenting with after market umbilical cords? The stock one looks solid, but I always wondered if getting an after market one would yield additional benefits.

Nobody?

 

[biosailor]

I dunno, low gain in itself should be blk, I stack and I’m blk in med gain. Methinks it’s somewhere else

I guess it must be something else. I put the amp and the power supply as far apart as I could: 75 cm in height, approx. 60 cm apart. I had the impression as if the hum got a bit better, but I am not sure.

While trying to connect my amp to a different plug, I used a normal power cable for the amp. What happened? The hum increased considerably! So, it might very well be a combined effect of XLR cables and power cables. Maybe I should invest into better power cables/XLR cables.

I also did a lot of reading about XLR cables (the pin 1 problem). Looks like some people connect pin 1 of the XLR to the shell ground pin, that seems to connect the XLR ground to the chassis ground of the equipment.

In any case, the hum is not bad, you have to go very close to the speakers to hear it. It does not disturb listening even at low levels. But, I thought it should be possible to get the system completely silent, just as is the case with RCA cables.

 

[biosailor]

Nobody?

I, too, would be interested in a longer cable.

 

[joseph69]

In any case, the hum is not bad, you have to go very close to the speakers to hear it. It does not disturb listening even at low levels.

Maybe try stacking the amp/PSU and listen if the hum increases.

 

[biosailor]

Maybe try stacking the amp/PSU and listen if the hum increases.

That‘s a logical step. Will try and report back.

 

[biosailor]

Maybe try stacking the amp/PSU and listen if the hum increases.

Tried stacking the amp on top of the PSU. And to much of my surprise, hum did not increase considerably, if at all there was a bit more hiss. Left me baffled!

I have spare XLR cables, and I'll solder pin 1 to the shell of the Neutrik plug and see if that lowers hum.

Anyhow, maybe I'm just nit-picking here. The hum is only audible when I put my ears literally onto my speakers.

 

[yage]

Anyhow, maybe I'm just nit-picking here. The hum is only audible when I put my ears literally onto my speakers.

Just to make sure it's not your amp - when you disconnect the GS-X from the system and power up only your amp, do you still hear a hum?

 

[biosailor]

Just to make sure it's not your amp - when you disconnect the GS-X from the system and power up only your amp, do you still hear a hum?

The power amp is dead quiet when the GSX-Mk2 is switched off. Switching it on immediately causes the slight hum.

 

[joseph69]

You're definitely not nitpicking, there shouldn't be any hum/hiss. I could have lived with it as well because as soon as the music played, the hum was inaudible.

I had the same exact issue, but with only 1 out of my 7 4-pin XLR terminated headphones (I didn't have the HD6XX at the time). My issue was a very faint hum in the right side driver of my PS2000e, but what was baffling was that this was the only headphone with the issue, so of course I thought it couldn't be any of my cables or the GSX, so it had to be these particular headphones.

I changed the XLR connector to no avail. I then contacted Grado and sent them in, but they didn't hear the noise (mind you, nobody but myself one other person heard the noise on my GSX and they also heard it with their PS2000e, but not on their own gear) so I figured it was so faint the one other person just doesn't hear it on their gear, nor does Grado. Grado changed out both drivers and the cable, sent them back to me and I had the same humming issue in the right side driver???

I then came across some posts here on this thread about the Mu-Metal and realized I shouldn't have the amp/PSU stacked, so I figured I'd try the shielding even though there was the only headphone giving me the issue, and to my surprise, the Mu-Metal totally solved the issue. And as I mentioned, switching between any gain the amp is dead silent. I still don't have the answer as to why only this 1 headphone had the issue (sensitivity?) but it's resolved and that's good enough for me. Keep us posted.

 

[biosailor]

Just to make sure it's not your amp - when you disconnect the GS-X from the system and power up only your amp, do you still hear a hum?

Also, I do not pick up any noise with my HD800

 

[joseph69]

PS: I did take full responsibility and contacted Grad telling them what the issue was, and also offered to pay for the services they provided.
They kindly declined my offer even though they weren't at fault.

 

[biosailor]

You're definitely not nitpicking, there shouldn't be any hum/hiss. I could have lived with it as well because as soon as the music played, the hum was inaudible.

I had the same exact issue, but with only 1 out of my 7 4-pin XLR terminated headphones (I didn't have the HD6XX at the time). My issue was a very faint hum in the right side driver of my PS2000e, but what was baffling was that this was the only headphone with the issue, so of course I thought it couldn't be any of my cables or the GSX, so it had to be these particular headphones.

I changed the XLR connector to no avail. I then contacted Grado and sent them in, but they didn't hear the noise (mind you, nobody but myself one other person heard the noise on my GSX and they also heard it with their PS2000e, but not on their own gear) so I figured it was so faint the one other person just doesn't hear it on their gear, nor does Grado. Grado changed out both drivers and the cable, sent them back to me and I had the same humming issue in the right side driver???

I then came across some posts here on this thread about the Mu-Metal and realized I shouldn't have the amp/PSU stacked, so I figured I'd try the shielding even though there was the only headphone giving me the issue, and to my surprise, the Mu-Metal totally solved the issue. And as I mentioned, switching between any gain the amp is dead silent. I still don't have the answer as to why only this 1 headphone had the issue (sensitivity?) but it's resolved and that's good enough for me. Keep us posted.

For sure I'll be trying the Mu-Metal, that's a great idea. Just need to find a vendor and I'll order it straight away!

 

[joseph69]

Also, I do not pick up any noise with my HD800

Same issue I had. No other headphone did this but my PS2000e