[GeorgeL]

 

Hello, I´m a long time reader but this is the first thread I start. I apologize beforehand for my writing/spelling, english isn´t my native language. My setup is: Macbook pro---Burson HA-160DS----Sennheiser HD650 or AKG Q701.

 

My HA-160DS arrived yesterday, bought it directly from burson, my previous amp/dac was a fiio e7/e9. The problem is I´m hearing a hum (low noise) with my 650s, the hum starts when I turn on the burson, it doesn´t matter if the source is connected or not, also the noise remains the same with the volume knob all the way down or up. 

 

The hum is barely audible but it´s driving me insane, when I´m using the AKG´s I can hear it but it isn´t as bothersome (almost inaudible). Is there any Burson owner that has experienced this problem?

 

[hodgjy]

Have you tried plugging it into a different electrical outlet?  Try one on a different circuit or even in a different house.  That way, you can eliminate the electrical source as the cause of the hum.
 
P.S.  Your English is excellent!  If you didn't say English wasn't your first language, I would have never known! 

 

[GeorgeL]

Thanks! Well I´ve already tried different outlets, guess I´ll try in a different house tomorrow morning!

 

[fabio-fi]

I own the Ds but never had any issue. 
 
Check this thread:
http://www.head-fi.org/t/567807/stax-srm323s-hum-on-right-channel/15 (similar issue)
 
But..before doing anything else contact support, just in case you need the warranty. 
 

 

[MohawkUS]

I've had the DS since December and it's starting to develop this quiet static hum. Figures, just as I decide to sell it, this starts. It usually takes a few hours of use before I start hearing it though.

 

[dukeskd]

I just got it a few days and I have had that noise ever since turning it on! Has anyone find a solution to this or should I contact Burson? The hissing is very quiet, but its there and when changing the volume, it never alternates.

 

[MohawkUS]

Nope, I've tried a few different things and the noise persists, well it comes and goes but I can't get rid of it permanently.


It plays even without a source connected, and with any of the inputs selected(not coming from DAC then?)
Turning the amp off at night vs. leaving it on 24/7 has no effect,
It comes and goes randomly, but usually sticks around for a few hours when it starts up; for me it seems to go through cycles: 2 hours it's there, 2 it's not, etc.
Volume has little effect on it; it even plays nearly the same volume all the way down and gets slightly louder as I crank it past 12 o'clock, which is much too loud for listening,
When the volume is all the way down I only get music, quietly, in the right channel, with the noise being louder than the music that low,
After 2 days of being powered up, the spot next to the headphone output, where the LED is gets hot to the touch, hot enough that I jerked away the first time I noticed it which was about when the noise started(I think),


I think I might email Burson sometime in the next few days, there seem to be a few of us with this issue, maybe they'll do a recall. I'm going to email them my findings above as well it would help to know what headphones you guys use, for people with and without noise. I've found that because of the 5.6Ohm output impedance it sounds really off-key(muddy, and un-natural, my Fuze is a major step up from the Burson with my portables though it doesn't have the drive or authority of the Burson, sounded like this with AKG K81 and Ultrasone PRO2900 which were unlistenable with the Fuze) with all of the headphones I've tried with it, all 40Ohm. Maybe there is some correlation between this problem, the heat, and the headphones we've been using.

I also think I should mention that when I first ordered the 160DS the re-seller accidently sent me a 160D, which was faulty. It only played out one channel and the channel that played was unaffected by volume, playing 100% at all times. Not sure if that means anything or not, but Burson seems to be having a lot of QC issues though the static problem took 2 months to appear for me.

 

[dukeskd]

The noise in my case does not go up when altering the volume, but its there all the time. When you put it to the max, you can hear the normal hissing of any device when the volume knob is put at max (especially when its connected to the laptop). But the noise sometimes is driving me crazy, at the beginning I thought it would go, but it's still here. I e-mailed Burson about it.

 

[GeorgeL]

The noise of my 160DS is exactly as dukeskd describes it, could´t find a solution but never contacted Burson. If they offer a solution or you find a way to make it stop please tell me. And MohawkUS the headphones I´m using are HD650 and AKG Q701, with the AKG´s its barely noticeable but when I´m using the 650 (most of the time really) its annoying. 

 

[dukeskd]

Yeah, I used my HD650, it is less noticeable than in my Denon D7000 probably because it leaks out more, but I can hear it. I also tested it with the SRH940 and DT990PRO, so its the fault of the amp no doubt.

 

[our martin]

send it back and get one of these audio lab mdac!

 

[dukeskd]

Appreciate the recommendation Martin
 
There is another post of this issue: http://www.head-fi.org/t/576308/new-burson-ha-160ds-integrated-dac-amp/105#post_8148334
 
It may be the DAC section of the HA160DS doing this.

 

[dukeskd]

Hey guys,
 
I received an e-mail response from Burson, this what they said:
 
Quote:

Yes, that is correct that is fairly normal for a pure class A design. To make sure the best audio quality we do not use any muting circuit for filtering cap to block out the noise.

 
Quote:

The low level of hissing sound is only the idling noise from the class A circuit. We can reduced idil current and reduce the noise but then it will not be a pure Class A design and it will certainly affect the sound quality of the 160DS.

 
So thats the answer from the folks at Burson, I was predicting that this was the cause but I never previously owned a pure class A design amp, except for the FiiO E7/E9, hence I couldn't speculate on this. If anyone here has another pure class A design amp (there are many) or are more experienced in owning them (I am looking at you milosz), do you have this idling sound?

 

[hodgjy]

I've heard plenty of class A amps that are dead silent. I don't buy what Burson is telling you. They're either too lazy to make a silent circuit or too lazy to fix it.

Hey guys,
 
I received an e-mail response from Burson, this what they said:
 
 
 
So thats the answer from the folks at Burson, I was predicting that this was the cause but I never previously owned a pure class A design amp, except for the FiiO E7/E9, hence I couldn't speculate on this. If anyone here has another pure class A design amp (there are many) or are more experienced in owning them (I am looking at you milosz), do you have this idling sound?

 

[johnwmclean]

^^ Thats a pile of bollocks, idle nose indeed.