Brownouts ....... and Brown-ins

My audio system - Luxman D10x, C700u, M700u, P 750u uses a PS12 to protect it from power surges and to regenerate the power. When the power goes out, the PS12 which is usually dark other than the front blue light, comes back on with the display lit up. Yesterday, we had a very brief brownout - a decrease in voltage - normally 118V to 90. Does the PS12 provide protection against a brownout? If not what does? Should I be considering a UPS? Or does this negate the benefits of the P12?
My concern is that some 30 years ago, I had a brown-in on a CJ EV2000 amp following several power outages due to downed trees and the gradual build up in power totally fried the unit.
Any thoughts or suggestions would be greatly appreciated.

Brown outs are bad for electronics. I had a ups protecting my system at one time, but the sonic improvement going from a ups to a P12 was night and day. I assume that the P12 does not compensate for brownouts, since it is not a backup power source, but regenerates the incoming power. If the incoming power is not all there, the P12 won’t generate new power if it isn’t there to begin with. Luckily I have not had any power issues while listening to music.

It seems like the regens can make up for low voltage using the internal caps but only around 10% if I remember correctly.

90 volts may not hurt all electronics but is deadly to electric motors. It will let the smoke out pretty quickly.


Paul - did you run the P12 off the UPS?

Best regards


In general brown-outs are unpredictable in nature. Under no circumstances should one operate equipment under sustained brown-out conditions. My advice in addressing a brown-out is to open the main feed breaker in your service panel and only re-close it when you are assured power has been reliably restored. Voltage provided by your electric utility can be unstable at the time of restoration causing significant damage to sensitive components. Yes, as others have said motors are also especially sensitive to extended low voltage conditions, especially at start-up. Keep in mind, circuit breakers or fuses do not necessarily respond as expected under low voltage high current situations.


Depending on the depth of the brownout, no regenerator which by design is dependent on the incoming AC mains, is always going to able to compensate for brown out anomalies. The regenerator circuit has finite input AC voltage latitude.

To be frank, were I you I would not be concerned about the SQ impact of falling back on a UPS when damage to your gear is the concern. Priorities. Live with degraded SQ during a brief brown out, if you are still intent on listening to your rig, until the brown out is resolved. Keep in mind although the power/distribution company does its best to avoid crazy gyrations on the mains when working the problem, that is never guaranteed. The alternative is equipment damage.

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I repeat, isolate if you are experiencing a sustained brown-out. Riding it out is not advised.

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What is a “Brown-in” I surmise it’s when the AC is restored to something near what it was prior to the brown-out. I’ve never heard of it before. Things that make you go hmmm :thinking:

Isolate what? And How?

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I believe the suggestion is that if having a brownout, turn everything off and unplug your system instead of connecting a ups and trying to continue listning to music during a brownout. For me, a brownout means just that.

Square D QO Series Load Center

An alternative is a fused disconnect switch suh as the one above.

Either the main service panel/load center or disconnect switch will be mounted immediately after the utility meter.

The ability to isolate will depend on you utility service and local electrical code to a degree. An example of a Squqre D QO series load center is shown above with out the circuit breakers installed. The very top circuit breaker is rated for the capability of the load center, 200 amps in this instance. The utility service comes into the top of the panel is fed into the 200 amp service breaker which then feeds two power buses. Each circuit (load) off the buss has a circuit breaker.

To isolate service to one’s home during a potentially siusained brown-out open the top main feed breaker, 200 amps in this example. Everything in your home is now isolated from utility circuits, no power in he house. Once utility has recovered from the brown out re-close the main panel breaker.

Another option is to unplug everything from the wall outlet, which is more time consuming, and depending on the nature of the brown-out can be somewhat dangerous. Refrigerators, well pumps, septic system pumps, sump pumps, air conditioners, electric furnace, and electric water heaters can be susceptible to damage due to higher currents flowing with reduced voltages associated with brown-outs. Power restoration following a service outage (black-out) or a brown-out can and often does result in voltage surges and significant voltage swings than can damage sensitive electronic components, as well as motors.

The first thing I do if there is a black-out or brown out is to open the main service feed breaker/switch. It is simple and effective. If I am gone for an extended period of time, as is with my summer home, sensitive equipment is isolated at the service panel.

Regarding voltage surges, a different topic, a whole house surge surpressor installed by a licensed electrician is recommended.


That photo reminds me of the movie “Airplane”


…that’s because the electrician is getting a charge out of it!

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