[hekeli]

Does anyone get physical transformer hum/buzz from inside the case? I'm sitting pretty near it so I can hear it quite well. 

 
I opened the case and tightened the transformer bolt which was pretty loose, no help.
 
PS. Why the hell did they use the most crappy small allen key bolts on the lid, sure way to strip them useless even if you are really careful. It's not like the drilled bolt holes felt very smooth either, some needed more force. I know I know, it's from China but..

 

[project86]

  This absolutely needs to happen!

 
One of these days it likely will.
 
 

  Does anyone get physical transformer hum/buzz from inside the case? I'm sitting pretty near it so I can hear it quite well. 

 
I opened the case and tightened the transformer bolt which was pretty loose, no help.
 
PS. Why the hell did they use the most crappy small allen key bolts on the lid, sure way to strip them useless even if you are really careful. It's not like the drilled bolt holes felt very smooth either, some needed more force. I know I know, it's from China but..

 
That's the first I've heard of it. Definitely get with Questyle about handling the situation - they will take care of you for sure.

 

[hydesg]

 

sounded even better. first thing i noticed was how deep the bass extended and tightly.
i hear even more things that I have not heard in the track. imagine was quite well improved as well. overall a superb upgrade. This is with the HD800.
 
with the LCD2, the bass gets abit boomy, but overall still superb. has that very intimate sound.

 

[hydesg]

  So far it's hard to analyse it. It has very peculiar responses with certain headphones.
 
All Senns sounded good. Never heard the HD650 sound so open and good (usually dislike that phone). Same goes for momentum. IE800 became even more colored and bass monsters (but enjoyable and very competent technically). The HE500 which is usually laid-back was harsh up top. Alpha Dogs lost their neutrality and became etched up high. And the spirit pro, which is forward sounding; became a shrill mess.
 
I have no idea what to expect!

just wondering what do you mean by etched up high? 
I have the alpha dogs coming in 2 weeks time though.

 

[Sonido]

  sounded even better. first thing i noticed was how deep the bass extended and tightly.
i hear even more things that I have not heard in the track. imagine was quite well improved as well. overall a superb upgrade. This is with the HD800.
 
with the LCD2, the bass gets abit boomy, but overall still superb. has that very intimate sound.

Do think it's worth it to get a second one? At $1000-1500 for one, it seems to beat competitors like Mjolnir and BHA-1 according to general consensus, and can give more expensive ones like the Taurus a run for the money, if not be on par or better for the HD800. But at 2x, it starts competing in the same price range against amps like the GS-X or the Bakoon.

 

[dleblanc343]

just wondering what do you mean by etched up high? 
I have the alpha dogs coming in 2 weeks time though.

The headphone is amazing. Its just with this amp that its a bit more forward a tad brightish

 

[hydesg]

  Do think it's worth it to get a second one? At $1000-1500 for one, it seems to beat competitors like Mjolnir and BHA-1 according to general consensus, and can give more expensive ones like the Taurus a run for the money, if not be on par or better for the HD800. But at 2x, it starts competing in the same price range against amps like the GS-X or the Bakoon.

i think its well worth its price.
single ended i thought it bests the alo studio six

 

[twsmith]

  Does anyone get physical transformer hum/buzz from inside the case? I'm sitting pretty near it so I can hear it quite well. 

 
I opened the case and tightened the transformer bolt which was pretty loose, no help.
 
PS. Why the hell did they use the most crappy small allen key bolts on the lid, sure way to strip them useless even if you are really careful. It's not like the drilled bolt holes felt very smooth either, some needed more force. I know I know, it's from China but..

It sounds like you may have a problem with DC offset ("DC in the AC") affecting the transformer and causing it to hum.  I had a severe problem with buzzing some years ago in an older Creek amplifier, and determined that it originated with the line (mains) current where I lived at that time.  You could try a simple test -- if possible, take your amp to another place that has a different mains supply -- maybe where you work, another person's house, etc. - see if you still have the buzzing, if it goes away, then it probably is DC offset.   Doing a web search will turn up a variety of possible solutions for this.   However I would first suggest contacting Questyle to discuss this problem with them, since they may have had other complaints about this and can offer some guidance.   It appears that some transformer designs may be more sensitive to DC offset than others.   

 

[igormsk]

I've got 3 headphones - HD800 (300 ohm), DT660 (32 ohm) and IEMs Shure SE215 (20 ohm). With HD800 the amp is absolutely silent, but with DT660 I hear hiss all the time no matter how high I set the volume - it's quite anoing when playing music without much dynamic range compression (nearly all recordings of classical music). When I plug my SE215 the hiss becomes so loud that makes listening to music unenjoyable.
 
I also tried plugging the same headphones into Yulong DA8 and Audio-GD NFB10.32 and got the same result - silence with HD800 and hiss (on DA8 not so loud but still present) with the other 2 headphones
Changing volume on the CMA800R and DA8 doesn't affect the hiss at all. On NFB10.32 the hiss volume changes significantly with volume settings (but not with gain settings) and is just audible on normal listening levels with DT660 and really disturbing with SE215.
 
Is there something wrong with my power at home or is this amp not suitable even for full size DT660 headphones? Would Yulong P18 help me to get rid of this hiss issue with low resistance headphones?
Before ordering P18 I could borrow http://www.furmansound.com/product.php?div=04&id=AC-210E - would it make sence?
 
If I plug DT660 into my notebook directly I don't hear any hiss (with SE215 there is some hiss but at a much lower level than on CMA800R / DA8 / NFB10.32).

 

[Chodi]

Igormsk-
 
If you have a battery backup unit available for one of your computers I would suggest the following to try to isolate the problem. Make sure the unit is fully charged and disconnect it from the wall power.  Plug in your amp and see if you get the hiss when it is on battery power. You will note that most of those type units only have one or two sockets which are active without wall power. It may only power the amp for a very few minutes but enough to test. The IEM's may hiss anyway but the other headphones should be silent unless you apply a lot of gain. If that is quiet then you need a power conditioner. Since you have three amps (one in the DA8) that have this hiss I suspect your power line. 

 

[igormsk]

I don't have any UPS with sin-wave (I'm not sure if I can plug this audio equipment into cheap stepped voltage UPS) to try..

 

[Chodi]

I don't have any UPS with sin-wave (I'm not sure if I can plug this audio equipment into cheap stepped voltage UPS) to try..

For the purpose of this experiment I don't see that it would matter. You are only powering the amp for moments to test. The ups purpose is to replace your wall power in an outage. If it does not prove a valid test you have lost nothing. I do not see how it could harm your equipment since it is a substitute for your wall power. I don't really see affordable ups with decent sin-wave but I don't think it is relevant.

 

[MoatsArt]

Subbed

 

[Vangelis]

John, did you ever get to trying the Auralic Vega Dac with Questyle CMA800?

 

[project86]

John, did you ever get to trying the Auralic Vega Dac with Questyle CMA800?

 
 
No, most of my time with Vega has not been in my own system. I had one come through briefly but only had time to use it with the matching Taurus amp. I see no reason why it wouldn't make a great combo though - I go the other direction and use Questyle's CAS192 with the Taurus all the time, with excellent results.