The HeadAmp GS-X and GS-X MK2 Thread
Mar 17, 2013 at 6:25 PM Post #736 of 6,326
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I don't care what you or other people have heard.     I'm saying on my unit - I hear no hum.   I have my TH-900 on right now.  Music off.  L / M gain  volume turned all the way up - nothing.  With the H gain - I do get a slight hum - very slight.  But why would I have it on H gain with these headphones???  
So Yes when listening to music on M / L gain with the TH-900s - I don't hear any hums..
 
WOW  I was just reporting I'm not getting this hum.  Now something must be seriously wrong with my hearing.  ha ha ha you guys make me laugh..

 
I get noise at high gain & high volume too (which sounds more like a hiss than hum) but the noise I've been referring to is an electrical hum, sort of like the buzzing that large electrical systems manifest but on a much smaller scale, directly in line with Justin's earlier post: "The transformers are also 66% larger so there is a larger magnetic field. To get the benefits of the separate PSU the amp needs to be placed away from the power supply; either side by side or at least 8" of vertical separation." If you can hear the high gain/high volume hiss, I'm not sure why you wouldn't also hear the transformer hum (which was audible to me at any gain setting or volume level down to Low gain and zero volume).
 
Perhaps it was out of line for me to say that something has to be wrong with your hearing (and for that I now apologize) if you didn't hear the effect of said magnetic field on the amp, but that magnetic field applies to every MK2, not just mine or 1 other person's. My earlier post was merely a counterargument for your statement that you didn't hear it - just because you didn't hear it, doesn't mean that it's not there, because the electromagnetic interference is there as a scientific fact (no this isn't the Sound Science forum, but that merits pointing out). I guess some people just can't hear it for whatever reason.
 
Update: I did some experimenting and found that the transformer hum lessens when the PSU is placed on top of the amp, so that could be a solution for anyone else that's bothered by it and doesn't have space to separate them. However, I'm not sure stacking the PSU on the amp is a good idea because the amp gets hotter than the PSU and probably needs ventilation more as a result. I'd highly suggest risers for anyone who intends on stacking the PSU on top of the amp. (Don't listen to this advice, see Justin's post below!)
 
Update #2: I also found that the AD2K is actually more sensitive to the transformer hum than the TH900. The AD2K seems to be about 150% louder than the TH900 on the transformer hum, and I can actually say that the hum is almost completely inaudible on the TH900 at low gain (but I can still still hear it faintly), but clearly audible on the AD2K. So I guess whether one can hear it or not also depends on which headphones are used.
 
The hum went completely inaudible on the TH900 only when the PSU was on top of the amp (configured to low gain), but that's the only way I got it to be completely inaudible. I heard it on the TH900 with every other gain setting and/or with the amp on top. And I still heard it on the AD2K even with the PSU on top, at low gain, so I still have to use the MK2 separated in order for it to not distract me.
 
Note: I deleted previous references to volume settings, because volume didn't affect the level of the transformer hum, only hiss on high gain.
 
Mar 17, 2013 at 7:19 PM Post #737 of 6,326
+1

It seems the sensitivity or impedence of the headphone seems to have a lot to do with it. The ad2k was a lot more prone than my other cans. The hd800 doesn't even need high gain IMO. Someone needs to try the k1000.

Nice tip on the PSU placed on top.
 
Mar 18, 2013 at 3:04 AM Post #741 of 6,326
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Very.  1+1=2   Sub whatever number you want.  Power on the other hand is 4x since current also double and 2x2=4 :wink:

understood
tongue.gif

 
Mar 18, 2013 at 9:51 PM Post #743 of 6,326
I get the same hum as Asr but have to use an IEM and have to go well beyond the level I could tolerate on the IEM to hear it.  But it's not power supply related since it's power supply is 4ft below it and everything else is powered off.  To be fair the B22 and Soloist do the same thing.
 
I can also add it the list of amps without ground loop breakers integrated in it so if it wins I'll need to find something to break the ground loop the USB input on the PWD2 creates or continue using toslink :O  That loop is again nowhere near audible even with the IEMs at reason levels but if you know its there and you can solve it easily... why not.
 
Going to let it warm up over the night and tomorrow while at work before I do any real listening.  Should add until I get my HD800 cables I'm running balanced in, single ended out to the headphones, balanced to the monitors.
 
Mar 18, 2013 at 10:41 PM Post #744 of 6,326
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When I turn off the amp, I hear a small but audible pop in my headphones. Is this anything to be worried about?

No worries. That happens to many headphone amps during turn-ons and offs.
 
Mar 19, 2013 at 6:40 AM Post #745 of 6,326
Hey guys, Do I lose anything if I am running SE into the amp and then balanced/HD800? I know the cans benefit from the balanced drive the GSX offers but what does keeping the signal balanced throughout the  chain offer? Thanks!
 
Mar 19, 2013 at 7:04 AM Post #746 of 6,326
Canta Ista, the GS-X must have a balanced input signal in order to  output balanced.  If you input a single-ended signal, then you will only get a single-ended signal out of the amp even through the XLR's
 
Mar 19, 2013 at 7:05 AM Post #747 of 6,326
I got an email from FedEx telling me my GS-X is on it's way, I should have it Wednesday.
 
I'm also in the process of using my MacMini as a music server to my Esoteric, to which I'm using my iPad as remote control to the music that's on the MacMini.
All my music which includes my CD's are on iTunes which is on my iMac, all I did was transfer iTunes from the iMac onto the MacMini.
What I need to do now is download Audirvana + to my MacMini and follow the instructions headfier astrostar59 has sent me.
After this is complete I won't need to play CD's on my source, the music will be coming from the MacMini and controlled by the iPad. Doing it this way I can listen to any song at random.
 
Mar 19, 2013 at 7:19 AM Post #748 of 6,326
Quote:
Canta Ista, the GS-X must have a balanced input signal in order to  output balanced.  If you input a single-ended signal, then you will only get a single-ended signal out of the amp even through the XLR's

thanks!
 
Mar 19, 2013 at 1:54 PM Post #750 of 6,326
I'll likely run an A/B of the GS-X and the B22 tonight.  Definitely with the HD800 maybe even as preamps.  Then again Thursday maybe against the Soloist.
 

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