LYR: Faint, staticky, high-pitched noise issue
Dec 24, 2011 at 5:10 PM Thread Starter Post #1 of 22

mrksgrn

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My setup is BiFROST > LYR > LCD-2
 
Having gotten the Lyr recently, I noticed that when there is no music playing, there is a faint, static-like high-pitched noise in both channels that appears and disappears periodically at around one minute intervals. Sometimes this noise can be heard in the background of quiet tracks. 
 
I have made sure there are no ground loops, and that the tubes (GE 6BZ7) are seated correctly (I even switched them), and isolated the problem to the Lyr. The noise can be heard without any input on the Lyr as well. 
 
Has anyone experienced this problem before? I suspect it's bad tubes but it's interesting that it's happening on both channels which point to the Lyr itself.
 
All comments are welcomed. Aside from this issue, I'm really enjoying this setup. 
 
Jan 3, 2012 at 3:18 PM Post #4 of 22
Long-time lurker, just received my Bifrost + Lyr and after 10+ hours starting to experience the same thing in the left channel.  Going to swap the tubes when I get a chance to see if the noise follows then call in when I come to some conclusion.
 
There's just a bit of background noise (hiss) but it's low and probably due to my 32ohm RS2i cans.
 
But there's a high-pitched crackling that occurs ever so often that is a bit distracting, but it is soft (almost sounds like digital noise to my ears).  This noise occurs without anything connected to the line-in as well, and isn't affected by the volume (and turning it up enough to drown out that noise sounds.. awesome!)
 
Like I said, I'll swap the tubes and give it a few more hours...  Since this occurred a week ago - any update?  Now that I have Schiit in my hands, I don't want to wash them :wink:
 
Jan 3, 2012 at 3:22 PM Post #5 of 22
Hi SeaHawk, 
 
I've just sent back my Lyr yesterday. Hopefully switching the tubes will work for you but it didn't work for me so Jason will treat this as a DOA.
Now to wait....sigh*
 
Jan 3, 2012 at 3:48 PM Post #6 of 22
Sorry to hear that (npi), as it's just "in the background" and doesn't seem to affect the actual operation of the amp.
 
Godspeed for your shipping and hopefully you won't suffer without for long.  I'll report back with my findings as I get more time to play this week.
 
Jan 3, 2012 at 10:05 PM Post #7 of 22
Swapped tubes and the stronger hiss followed to the other side, but the sporadic noise is still in the left channel...  It still sounds digital in nature, so next step will be moving it to another room away from electronics, to ensure it's not EFI/RFI related.  Been meaning to hook a turntable directly to the Lyr, anyway :)
 
Jan 4, 2012 at 1:31 AM Post #10 of 22
It could be tube microphony. If you touch the top of the tube and you hear crackling then that's what you have, a microphonic tube. Tubes can also have that background noise without music playing. That's just their nature. Some are quieter than others. Cleaning their pins help. You can use 91% Isopropyl alcohol. I use the smallest drill bit, wrap it with thin cotton pad, dip in the alcohol and clean each tube pin.
 
Jan 4, 2012 at 1:40 AM Post #11 of 22
Tried tapping the tubes (even ever-so-gently rocking them in the socket) but only the very faintest of noise from that (and seemingly unrelated to the aforementioned noise issue), even tapping around the case.  (As mentioned, swapping them didn't change the affected channel, and gently tapping indicates the front socket is the left channel, rear socket the right.
 
Haven't had a chance to move it elsewhere and likely won't today, but next on the list.  (EFI/RFI issues)
 
For the past 30 mins or so there hasn't been any noise, so crossing fingers (though it seems to be the SS side of affairs, which is a bit troubling).
 
I do appreciate the suggestions! :)
 
 
Jan 4, 2012 at 2:38 AM Post #13 of 22
Try sitting your GSM phone on top of a cheap boombox...  Or live down the street from some guy who has his CB radio jacked up beyond what's allowed by law.
(Not saying I know what part is susceptible, be it power supply or flux capacitor, but I just know what comes out the speakers ain't supposed to be coming out the speakers :wink:
 
Jan 4, 2012 at 2:44 AM Post #14 of 22


Quote:
Try sitting your GSM phone on top of a cheap boombox...  Or live down the street from some guy who has his CB radio jacked up beyond what's allowed by law.
(Not saying I know what part is susceptible, be it power supply or flux capacitor, but I just know what comes out the speakers ain't supposed to be coming out the speakers :wink:



I placed my cellphone next to my tube amp, ss amp, DAC, portable DAC, portable amp, next to my Wi-Fi router, I don't hear any RFI.
 
Jan 4, 2012 at 12:44 PM Post #15 of 22
Call it, or send a text message so that it's actively transmitting, not just passively receiving (note, GSM phones are very bad about this which is why I mentioned it, so if you're using Sprint or Verizon (assuming you're in the US) you might not get the effect - CDMA is spread-spectrum and "cleaner" RF-wise).
 
You'll hear noise in clock radios, computer speakers, mostly cheaper electronics without very good shielding (not saying that any of your devices or the Schiit-y (!) ones are not shielded well enough), but keep in mind I listed it as a possibility, not necessarily a probability.. and the thread is going off-track..  It's all good, though :)
 

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