Auto on Circuits - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: August 11, 2015, 01:43:43 pm
content: Hi all, I know these auto on power circuits generally leave a lot to be desired, but mine works surprising well on my new Emotiva a-100 amplifier, that is till the central air powers on. That will cause my amp to turn on while in auto power on. Is there anything I can do to suppress this voltage spike? I tried an APC surge suppressor, but that does nothing.

author: tony3d
author_rank: Frequent Contributor
timestamp: August 12, 2015, 04:31:50 pm
content: Ok, I thought maybe the input cable to that amp was picking up noise, so I put a very high quality shielded cable on it. same problem,the amp comes on if the air conditioner turns or, or I flick the wall fan switch, and the amp goes on. So, I tried braiding the cables. same problem. Next I tried my iPod, and that works fine. Soon as I plug the cables back into the Mac I get the problem. So I guess the noise is coming straight through A/C connections. Is there anything (short of finding another outlet), I can do to filter this out?

author: Chris C
author_rank: Frequent Contributor
timestamp: August 12, 2015, 06:14:38 pm
content: A surge suppressor just absorbs spikes that occur at several times the normal line voltage. What may work for you is a power conditioner, which filters out small surges/dips regardless of voltage, that are at a higher frequency than the normal 50/60hz powerline. That's exactly what large motors like in your AC or fan produce.But if you have an issue with the AC wiring in your house, this may not work, or may require a very large/expensive conditioner. In which case it might be better to solve the underlying problem. Do your lights briefly dim when these motors turn on?Also, this is a fairly high end audio component, and I'd expect nothing less than excellent customer service from the manufacturer. Have you contacted them to see if they have any suggestions? It's possible it's a known issue, for which they already have a solution.

author: tony3d
author_rank: Frequent Contributor
timestamp: August 12, 2015, 08:21:13 pm
content: No I have now issues with lights dimming when turning on a fan or even when the air conditioner kicks on. I think they just have the sensing circuit to sensitive. If I simply take the audio outs from my computer, plug them into my iPod, it works fine. So somehow I think the computer is picking up the line noise, and passing it over to the amp through the amp inputs. I guess I can just switch it to remain on all the time, or manually turn it off.

author: Chris C
author_rank: Frequent Contributor
timestamp: August 13, 2015, 09:45:02 am
content: Ah, thanks for the clarification. Your success with the iPod suggests another possible solution, connecting the computer to the amp through a ground loop isolator. This is cheaper/smaller than a power conditioner. An example:http://www.amazon.com/PAC-SNI-1-3-5-3-5-mm-Isolator/dp/B001EAQTRIThough I'd still contact the manufacturer. It's possible they've left the sensitivity of the auto-on circuit adjustable via trimpot.

author: tony3d
author_rank: Frequent Contributor
timestamp: August 14, 2015, 01:53:13 am
content: I can ask them if it is adjustable, but I rather doubt it. I ay try what you suggest here. The amp is elf is really clean. I like it a lot.