The HeadAmp GS-X and GS-X MK2 Thread

[stevenator]

Mu-Metal placed on the underside of the amp mounted via the 3 foot holes.

Are you saying you essentially have a metal plate under the amplifier unit? Is it something like this?

 

[stevenator]

Unless you have AC hum from ground loops—and I do not think you do—hum from EMI is not difficult to eliminate as it decays as the inverse of the square of the distance. I had a slight hum when I stacked the two units and using RCA cables.. I just used Navcom feet to separate the stacked units by about two inches: problem solved. I never had any problems with all XLR input and output.

I don't think it's a ground loop either. Where did you find the feet you're using? As I mentioned, the feet I've come across generally aren't very tall, usually 7/8" or less.

 

[Justin_Time]

I did it two ways and they both worked.

One way is to use the Audio-Technical feet. They can be adjusted to almost 2 inches tall. Another way is the double up on the Navcom feet which make them about 1;and 3;4 inches tall. So you need 8 of them or six if you like. The nearly 3 inch gap between the units—with the amp’s feet—was more than enough to eliminate the hum and also gave the units plenty of room to breathe.

In both cases, the silver metal bands around the feet match the color of my GS-X. Mk2.

 

[joseph69]

Are you saying you essentially have a metal plate under the amplifier unit? Is it something like this?

Yes, I ordered a custom cut piece of .030 Mu-Metal from
The MuShield Company and mounted it to the bottom of the amp chassis by drilling 3 holes in the Mu-Metal where the 3 feet are located. I then took the feet off, then placed the Mu-Metal against the chassis, then put the feet back on to secure the Mu-Metal. Yes, that is basically what I bought.

 

[Thenewguy007]

Yes, I ordered a custom cut piece of .030 Mu-Metal from
The MuShield Company and mounted it to the bottom of the amp chassis by drilling 3 holes in the Mu-Metal where the 3 feet are located. I then took the feet off, then placed the Mu-Metal against the chassis, then put the feet back on to secure the Mu-Metal. Yes, that is basically what I bought.

Would that be safe in wrapping around the transformers inside the amplifier & power supply for added EMI/RFI protection?
Or would that be a bad idea to have a wrap around an additional conductive metal inside a active (when its later turned on) amp?

 

[joseph69]

I'm definitely not the one to be asking this question. I pretty much posted the question to the HeadAmp Team if it was safe to use the Mu-Metal because approximately 3/4 of its composition is a nickel-iron soft 'magnetic' alloy and I was afraid the magnetism may interfere with some other internals of the amp/PSU. I never received a reply. It was confirmed to me to be safe to use by a knowledgeable member, though, so I was more than comfortable trying it after his reply to me.

EDIT: Mu-Metal was also suggested to @T Bone by Justin. I totally forgot about this while I was replying, sorry. And @paradoxper confirmed it was safe to use as well.

 

[brianza]

HELP: TO ALL GS-X mk2 + HD 800 / S OWNERS​

This is my 1st post here on Head-Fi, after many many hears of reading the forum and checking out site/youtube channel. I've been posting in some European hi-fi forums, and finally subscribed here: thing I was going to do anyway, to join the GS-X community.
YES, I'm also a fresh GS-X mk2 owner since this week, and yes I'll post some pictures and impressions for sure. I've been dreaming of it for about 2 years, since I saw a blue unit for the first time and thought... "Holy crap this probably sounds as awesome as it looks".

GEAR: My reference headphones are LCD-X, HD 650 and the most early acquired HD 800 S, all balanced terminated. GS-X hooked up to various balanced sources through silver XLRs.

ISSUE: I'll cut it and get straight to the point: it sounds fabulous with all my headphones, even with my older and beloved beyers, and my old grados... EXCLUDING THE HD 800 S (which has worked flawlessly with every amp I've tried I tried with it).
Now, I'm not talking of synergy or subjective opinions, I'm talking about some nasty and really strange interference going on. Basically I'm hearing clear interference noises, when turning the DACT knob from zero 0 to through the first 3 steps of volume, all of this culminating in a loud "high pitched" frequency noise when the knob is fix on the 3rd volume step. Just in LOW GAIN, and just on 3 first steps of volume. From step 4 to 24 in low gain, everything sounds normal and dead silent. Same dead silent from step 0 to 24, respectively in MID and HIGH gain.
I stopped the music: noises on the first 3 steps still there. Unplugged the source, and put the GS-X alone, just powered and running alone, on my kitchen table, with HD 800 S plugged in. Still noise.

TEST: I basically perform this test with the amp powered up and no source connected: going from mute through all the 24 x 3 gain DACT volume steps, for a total of 72 positions, with every headphone I could try. Dead, pitch, SILENT, with all headphones, even on step 72, max volume on high gain.The HD 800 S show again any signs of noise or problems when used in mid and high gain, just the first 3 steps of low gain. The funny thing is that the noise changes by just moving my head around or the cable on the desk itself: it changes pitch, note, like a high freq. musical instrument. I could also get it to completely muted and silent, on random positions. Even if "muted", I still could hear noise when turning the knob.

I thought about the cable, which is the stock 4 pin XLR (ch 800 s). Swapped the still new 6.3 jack, stock senn cable, and tried the L and R unbalanced combo jacks. It got even more WIERD. All kinds of crappy high pitch noises and disturb, randomly, on the first 3 steps, even on step zero 0. I also got all kinds of noise just by turning the jack when plugged into the amp. None of this happening with every other headphone. I tried changing AC outlet plug from the wall, no difference. Stacking or 1 meter away, no difference at all.

FORTUNATELY: Justin came back with an answer after just 5 minutes I wrote him. A brief but right explanation as he stated, and I'm still waiting from other answers and comments from him.

"Are you saying this issue only happens in low gain? Please confirm that. If so, there is likely an easy explanation, which is that you may have stumbled upon a configuration that causes some instability in unity gain (low gain). Many, many amps are not unity gain stable and this is why they have minimum of 2x gain. The GS-X mk2 is stable in unity gain (1x) however there could be rare instances where a particular set of conditions (balanced output, certain headphones, certain cable, certain cable lengths, environment, etc) could cause this to happen. It's very possible that it might not happen with a different HD800S, but that your HD800S would also not be considered defective in any way. I would recommend that you use medium or high gain."

Now, THIS IS FAR FROM SOLVED IMHO, and really want to fix this, as I seem the only poor guy around here to have come up with this issue. I've searched deep in the web, and didn't find any report of something like this with an HD 800 / S. Not a report of this issue by a GS-X owner. And apparently many people here on Head-Fi, succesfully driving the HD 800 with th GS-X.

HEADPHONE or CABLE? GS-X works flawless with every headphone. HD 800 S works flawless with every amp. BUT, together they apparently go NUTS.
Before going through much hassle, with the headphone itself, I thought about trying some other cables. I know BOTH stock cables, apart from the connector, are equally created: I think this may bring in a capacitance / impedance issues, with both.
I will try for sure to test the GS-X with another HD 800, probably from a local gear shop. I know in a way I will be able to get a brand new HD 800 S from the pro shop I bought it from (6 months ago), thorough warranty, just want to be sure where this mess is coming from.

REALLY APPRECIATE YOUR HELP

Andre

 

[Whazzzup]

disconnect everything, reboot everything. Include your dac. Do not use the a/b se hp inputs. Get back to 4 pin xlr. Should not happen. Can’t say I had the same thing but got some funk once trying se l/r never did that again.

 

[cooperpwc]

@brianza Do you mean:

The HD 800 S do not show again any signs of noise or problems when used in mid and high gain, just the first 3 steps of low gain. The funny thing is that the noise changes by just moving my head around or the cable on the desk itself: it changes pitch, note, like a high freq. musical instrument. I could also get it to completely muted and silent, on random positions. Even if "muted", I still could hear noise when turning the knob.

?

If so, Justin seems to have explained it. It is difficult to imagine any explanation other than a rare unity gain issue. There is also no scenario that I can think of where low gain would be the best choice for the HD800 series. Your setup is fine.

 

[T Bone]

"Are you saying this issue only happens in low gain? Please confirm that. If so, there is likely an easy explanation, which is that you may have stumbled upon a configuration that causes some instability in unity gain (low gain). Many, many amps are not unity gain stable and this is why they have minimum of 2x gain. The GS-X mk2 is stable in unity gain (1x) however there could be rare instances where a particular set of conditions (balanced output, certain headphones, certain cable, certain cable lengths, environment, etc) could cause this to happen. It's very possible that it might not happen with a different HD800S, but that your HD800S would also not be considered defective in any way. I would recommend that you use medium or high gain."

Now, THIS IS FAR FROM SOLVED IMHO, and really want to fix this, as I seem the only poor guy around here to have come up with this issue. I've searched deep in the web, and didn't find any report of something like this with an HD 800 / S. Not a report of this issue by a GS-X owner. And apparently many people here on Head-Fi, succesfully driving the HD 800 with th GS-X.

I don't intend to come off as a pr*ck, but if Justin says you're having a unity gain issue - you can pretty much take it to the bank.
Not sure if you're looking for an alternative answer to Justin's hypothesis or trying to find someone else who is experiencing the same bizarre condition.

 

[brianza]

First of all, thanks everybody for your feedback!

disconnect everything, reboot everything. Include your dac. Do not use the a/b se hp inputs. Get back to 4 pin xlr. Should not happen. Can’t say I had the same thing but got some funk once trying se l/r never did that again.

Already tried everything half an hour an ago after coming back home... Same situation as last week
But hey, are you telling me you're experiencing some strange, stuff that shouldn't happen, when using the SE left and right inputs? This is quite interesting... and honestly not good. I suppose for a mysterious reason the GS-X might be negatively sensible to the HD 800s. I suppose you're using stock cables, have you ever ahd the chance to try other aftermarket ones?

Anyway if you're saying your HD 800 S is dead silent on 4 pin XLR, mine should be too. I definitely have a problem somewhere.

@brianza Do you mean:
?

If so, Justin seems to have explained it. It is difficult to imagine any explanation other than a rare unity gain issue. There is also no scenario that I can think of where low gain would be the best choice for the HD800 series. Your setup is fine.

That's the only explanation, no doubt about it. Whazzzup up here is reporting no noise when using 4 pin XLR... I think I'm not that fine. Unfortunately I also like to listen at low and relaxing volume levels, and for me the low gain option, with its granularity, it's very useful. Also very nice to be able to switch from low to mid, depending on the loudness of the material you're listening too. I also know this highly subjective. Have you ever encountered any issues with yours?

I don't intend to come off as a pr*ck, but if Justin says you're having a unity gain issue - you can pretty much take it to the bank.
Not sure if you're looking for an alternative answer to Justin's hypothesis or trying to find someone else who is experiencing the same bizarre condition.

Hi T Bone... No problems at all here, I perfectly get what you mean! I'm not trying in anyway to find alternative answer, I've been talking to Justin several times, and I have a lot of respect for its knowledge.
I'm just trying, as you say, to find is someone else is experience this bizzare-ness.
We're in front of almost 400 pages! of thread, and I've seen so many people using HD 800 / GS-X combo, and apparently, again "apparently", no one is experiencing issues of any sort.

I don't want to sound as a pr*ck too, but hey: we're talking almost 5K $$$ of gear here, for me is really unacceptable to have any issues at all, also "smaller" ones, like this unity gain thing. Especially when I'm apparently the only one. It's also a matter of principle.

Anyway I'm honestly 95% sure the HD 800 S it's the problem here... Any more helpful feedbacks out there?
In around 10 days I'll probably be able to try another brand new HD800 S. I'll see meantime if it's worth the hassle or not...

 

[eee1111]

SU-1 to Holo Spring to GS-X mkII

what switches need to be changed on the SU-1?

 

[T Bone]

SU-1 to Holo Spring what switches need to be changed on the SU-1?

* NOTHING *

The factory settings on the SU-1 match the Holo Spring.
If you absolutely need verification, visit the Kitsune HiFi - Tim has a schematic reference of the pins and setting on the Holo page.

 

[T Bone]

I don't want to sound as a pr*ck too, but hey: we're talking almost 5K $$$ of gear here, for me is really unacceptable to have any issues at all, also "smaller" ones, like this unity gain thing. Especially when I'm apparently the only one. It's also a matter of principle.

Yeah, I completely understand where you're coming from. When you drop that kind of $$$ you want everything perfect and magical.

 

[brianza]

Yeah, I completely understand where you're coming from. When you drop that kind of $$$ you want everything perfect and magical.

Nice one! I'm not saying neither perfect of magical, something that just works as supposed, and apparently works most of times, as with nice quality gear. I've been going through dirt cheap cassette, cd players and earphones when young, and honestly never spent this much on headphones ever before. Anyway I work with electronics, and I'm not that stoopid to keep myself something that doesn't work as intended even after many troubleshooting), as people normally do. Thanks for your useful feedback