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I have a lampucera dac which I am pretty happy with. I have one annoying problem with it though, when switching certain lights in the house, the ones with dimmers, the dac will mute intermittently. It's a very short interruption that occurs only during switching, but I can't imagine what it is. No other electrical gadgets in the house exhibit any such behavior.
Anyone have any idea what might be causing this?
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I do not allow those in my house. They are noisy unless you get an expensive transformer-based one.
lift the AC safety ground if there is one and see if it still happens. That is if the coax cable to the DAC doesn't solve it. The dimmer probably doesn't even have the third green safety ground connection. On the mains panel the neutral and safety grounds are common and the real issue is what the DAC does or doesn't do with that connection internally if there is one.E
T
Edit: and try the source(s) too
Edits: 09/07/15 09/07/15 09/07/15 09/07/15
Change the coaxial cable.
Substitute it with a cheap video cable first.
The type that you get supplied with with a cheapo DVD player.
Confirm that the interface is stable and move on to trying other 75ohms terminated coaxial cable.
I am using a usb to coax adapter from my pc. I'll have to try coax from my dvd player to see if problem occurs there.
Your DAC interface receiver is momentarily losing lock - best interface jitter tolerance is obtained with a long time constant which means you can lose data with burst interruptions.
If you are able to run an optical link between your PC and the DAC, then you can determine if the issue is conducted or radiated EMI. An optical link will eliminate the electrical interaction between DAC and PC.
Impedance mismatch would result in increased interface jitter which may increase the likelihood of the DAC losing Lock, but since you say that the dropouts only occur when you switch a dimmer, this would suggest a vulnerability to EMI. Most likely this is through the power supply. This may either be coupled through from your PC which may corrupt the transmitted data through the USB adapter, or through the DAC power supply (or both!).
Do you know if the USB adapter is galvanically isolated (i.e transformer coupled)?
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
I have found that the problem only occurs with my usb/coax adaptor. Problem complete disappears with straight coax from my dvd player.
Which suggests noise injection via the PC. I assume the USB interface is bus-powered - the PC power supply is usually very noisy.
Regards Anthony
"Beauty is Truth, Truth Beauty.." Keats
Dimmers generate a lot of noise (RFI) When you turn it on or off it sends out a strong pulse which your dac is reacting too. If you do a search there are low noise dimmers available
Alan
Commonly used dimmer switches are very noisy, so you may be picking up a big glitch on the digital cable or on the power line when it is switched, and so could be momentarily dropping out of lock on the digital input, so it mutes.
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