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  3. 134793-25

Having a problem when HVAC system turns on and cuts my system off!

Ok here’s the deal smart Agoners. I have been in this new house with pretty much the same rig with no issues for a year or so. I play music pretty much all day now in our living room space that opens up to the kitchen. Several times throughout the day, not every time, when the HVAC system turns on it will cause my computer server usb connection to the dac to fail. Usually a few seconds after the HVAC turns on the USB signal is lost.....cuts out?

My system is on a dedicated 20 amp line with two levels of conditioning before the dac and computer server. A BPT balanced conditioner feeding two Core Power Technology balanced conditioner/cords to my system. See my virtual system for a better understanding.

I have have to turn off the dac and turn it back on to re-initiate and play music again. My dac is built into my amp just as an FYI. What the heck is going on and what is the fix?

Must be some kind of electrical surge or such that is somehow impacting my direct AC line and system. Strange. Happening more often of late.

128x128grannyring
grannyring's avatar
grannyring OP
4,637 posts
 
@steakster

I think you are onto something. Please give me some external ground options. I assume the outlet plate screw won’t qualify?

No doubt the issue is linked to the turning on of the HVAC unit as there is a 100% correlation.

@almarg The volume has no impact. HVAC for heating is the cause right now. I think you are right to suggest pulling out one LPS at a time to test.

Thanks guys! 
steakster
720 posts
 
Depends on the design of the outlet & outlet box. This theory could be tested by running a ground wire to the plumbing. But, it won’t work if it's PVC. Is there an external ground lug on any of your power conditioners?
jbrrp1
215 posts
 
I had something akin to this happening with my computer feeding USB to my Lampizator Golden Gate DAC, where every time the AC kicked in the music stopped for ~ 5 - 8 seconds, but then it would reestablish connection and continue.  Of course that gap drove me nuts!  Worse yet, it wasn't just my AC, but also my many neighbors' AC systems that triggered this event.  I'm guessing a momentary power line sag occurred from the start up capacitors in the AC systems.

I tried a Topaz isolation transformer on the line, both in normal mode and in balanced mode, and it did not help.  What did solve this problem for me was to try a PS Audio P-10 power regenerator.  This stopped the maddening interruptions that I was suffering, and it actually sounded almost as good as my best power feed set up (Topaz in balanced feeding a very expensive power cord feeding an equally expensive HB Marble power distribution bar).  Now I have enjoyed continuous play for 18 months and counting.  It might be worth a try in your system (and might give your system's sound quality a boost, too).
mattmiller's avatar
mattmiller
1,180 posts
 
I still say your not isolating anything unless you get rid of the USB and go Optical from the computer. All these isolation devices dont help.


Matt
grannyring's avatar
grannyring OP
4,637 posts
 
Thanks all. I did two things that may have cured the issue. 

- the iFi Micro USB 3 has a grounding switch.  Manual says to defeat it and cut the ground. Well, instead I decided to engage the ground switch 

- I plugged one of my LPS units in a different BPT conditioner outlet

It has not happened since.  Hope this is it!
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