[slackman]

I was merely joking about Machina Dynamica. At one point their "tweaks" were pretty out there, but just barely rooted enough in reality (or someone's version of it) to convince a few audio nuts that they actually did something

At this point I strongly suspect they have tipped their hat to us, revealing that it was a farce all along, without actually saying those words. I'm hoping the whole thing is a long term social experiment, where they can stand up and tell the truth soon, making the joke on Positive Feedback, 6moons, and all the others who took them as a serious company. 

Haha nice.
You have humor sir

I'm hoping along with you that it's an experiment and they come clean at some point. Would be good for the audio community.

 

[Somnambulist]

Guys, I'm hearing a slight today hum with my D18. This is generated by the DAC itself, and it's not coming from the speakers. It's not loud, but audible enough in silence to notice, and it bugs me, especially as I'm sure it wasn't there yesterday. Any ideas?

 

[project86]

Odd, especially since it wasn't there yesterday. What changed? 
 
I would start by isolating it from other gear, or equipment like phones and televisions, to see if it is interference. Also try different power outlets and see if that has anything to do with it. Make sure the fuze is secure too.

 

[Somnambulist]

I think it's more likely that I didn't notice it because I was listening to music non-stop before. Anyway, it's most audible when you press the power on button, then decreases in volume but is still present. I wonder if it's the transformer vibrating? I might open it up tomorrow and see if it's loose or something.

 

[drez]

ground loop?

 

[Somnambulist]

Here's a quick vid before I go to bed. My speakers are turned off.
 

 
I think you should be able to hear it pretty clearly. 
 
EDIT - turn the volume right up though, phone camera isn't very good.

 

[project86]

Sorry I couldn't make out anything in the video. But just to confirm - this is a physical hum produced by the device itself, not something coming from the outputs?

 

[Somnambulist]

Yes. I have disconnected everything but the power cable in the video (I used the same cable with the D100 and it was silent). The video camera on the phone introduces a lot of background hiss and there's the Mac Mini's noise as well, but if you turn it up loud (way, way past listening level), you should be able to hear the hum when it's turned on and off. There are no surprise loud noises to make you go deaf haha. In real life, the initial buzz is very audible and once settled is audible enough to be distracting if there's no music playing.
 
I've contacted the ebay seller, who's been fantastic so far and has contacted Yulong for me. He can hear the buzz too and thinks it might be the transformer. The voltage on the device is definitely on the 220-240V setting, and in the UK we use 230-240V, so that shouldn't be introducing this noise.

 

[Grant Fidelity]

I wouldn't be turning it on and off as fast as you are in your video, let things discharge and charge properly, at least one minute. Do you feel any vibrations in the casing?, unplug and check to see if the transformer's mounting bolt is tight, then loosen and re-tighten to about 20lbs of torque. How many hours?, the tranny or power filter caps might need some time to sort out. While inside look for any signs of failed power filter caps, bulged ends, leaks, burn signs. Have you tried it on some other outlet or even a friends home, just to make sure it isn't the circuit, try different positions in your power bar and remove power bar, straight into wall. Have you tried another power cable, sometimes power cables are hot/neutral reversed, more often the wall receptacle is hot/neutral reversed, some gear is much more sensitive to this. If you find it is working fine on other outlets or a friends house then you might want to consider testing your wall voltage, voltage drop, rms and peak to peak voltage, hot/neutral polarity, due to "fried a customer" liability issues I'm not going to describe how to do this
 
Since you have reported the issue to your seller and assuming he/she is going to take care of you, I'd hold off returning it for a week or two to see if sorts itself out. More often than not things that get returned to us for issues end up being fine when tested. We have no reports of this issue to date.
 
Hope that helps,
Ian

 

[Somnambulist]

Thanks for the reply:
 
No vibration in the casing.
Hours = approaching 100 I'd say
Tried it in the wall in several locations, power strip etc - still buzzes
Tried it with the EU power cable it came with and an adapter instead of just the UK plug - still buzzes
The mounting bolt is the singe bolt that sticks out of the bottom of the case right? I'll try that now... that doesn't tighten, it just turns and turns, so I guess I'll have to have a peek inside. Which screws need to be taken out to open it up? (I presume it's the front and back 4 in the corners)
 
As said, the D100 never did this so I'm more inclined to believe it's the D18 than my house or cables or wiring, although I'd be happy to be proved wrong.
 
 
Quote:

I wouldn't be turning it on and off as fast as you are in your video, let things discharge and charge properly, at least one minute. Do you feel any vibrations in the casing?, unplug and check to see if the transformer's mounting bolt is tight, then loosen and re-tighten to about 20lbs of torque. How many hours?, the tranny or power filter caps might need some time to sort out. While inside look for any signs of failed power filter caps, bulged ends, leaks, burn signs. Have you tried it on some other outlet or even a friends home, just to make sure it isn't the circuit, try different positions in your power bar and remove power bar, straight into wall. Have you tried another power cable, sometimes power cables are hot/neutral reversed, more often the wall receptacle is hot/neutral reversed, some gear is much more sensitive to this. If you find it is working fine on other outlets or a friends house then you might want to consider testing your wall voltage, voltage drop, rms and peak to peak voltage, hot/neutral polarity, due to "fried a customer" liability issues I'm not going to describe how to do this
 
Since you have reported the issue to your seller and assuming he/she is going to take care of you, I'd hold off returning it for a week or two to see if sorts itself out. More often than not things that get returned to us for issues end up being fine when tested. We have no reports of this issue to date.
 
Hope that helps,
Ian

 

 

[Grant Fidelity]

4 screws on the back and 4 bolts on the front, the transformer has come loose, likely in shipping (any signs of mishandling on the package?), the bottom bolt should be tight, but you need to access the nut on top of the tranny to tighten, I'd say you are very close to sorting
 
Cheers,
Ian

 

[Somnambulist]

It's dropped the digital connection now and won't pick it back up. The cable is fine as well and still showing as being a working digital output at the Mac end.
 
I haven't fiddled with anything inside or opened it up yet. Hopefully tightening the transformer will work, otherwise I'll be a sad panda.
 
EDIT - how typical, I have every size allen key except the one that fits the rear screws. *sigh*

 

[kr0gg]

Quote:

. Do you feel any vibrations in the casing?,

what would vibrations mean?

 

[Somnambulist]

Transformer loose and touching the casing, or something like that.
 
Still waiting for the seller to get back to me. Good thing this has a 2 year warranty... can't believe my luck though, had one of my Focals suffer a volume drop recently and had to send that off for repair and was listening in mono for a few weeks before it came back, now this. 

 

[project86]

Yeah that is too bad. I still wonder if it might be something you can fix at home yourself? Without understanding the exact nature of the defect I guess I can't say for sure.

Sometimes I just have a run of bad luck - 2 or 3 defective products in a row. Then all perfect for a while, then back to RMA land once again.... I seem to do worse with computer equipment than audio gear. I once got three bad routers in a row, all different brands, all brand new, all well known/reviewed models.