What is the lowest voltage acceptable ?

in NA the standard voltage is 115v if its a little higher or lower its not a big deal, ie +/-5v. i would not concern your self specially on the slightly lower side. if it goes much lower or higher I'd contact your provider. 

This is governed by your state’s utility regulatory agency, such as a Board of Public Utilities. My state respects the ANSI C84.1 guideline, which calls for a ± 5 percent regulation of the nominal 120VAC service, or 114 volts minimum.

I agree 114 should be the minimum, but the other really hot night Con Edison had some outages a couple of miles away from me and my voltage went down to 109 in the evening. I unplugged my system. The next day it went up to 119 and 115 at night . I emailed my provider ( Con Edison )  and am waiting for a reply.

I use a Furman AR which keeps my line voltage within a consistent 118 to 122 VAC, barring severe issues (in which case it shuts off), as well as protecting me from white outs as well. The most compact/affordable combination is this unit.

In my case, I bought an Elite 15i first, and then realized I needed the voltage regulation, so I have probably spent 3x that much on my setup. Don’t do what I did. 🤣

Furman should do just fine. I use older PS Audio regenerator that does voltage regulation too, in addition to other things. They are quite expensive even used and don't always work with powerful power amps, it depends on particular model.

If you're worried about it come and get my TrippLite LC-1800.

I’m using this at present: CyberPower CP1500PFCLCD PFC Sinewave UPS System, 1500VA/1000W, 12 Outlets, AVR, Mini Tower,Black https://a.co/d/08AKYmj9

I’d say 115V should be the lowest acceptable voltage; as others have mentioned, standard US wall outlet voltage is now 120 VAC (half of 240 VAC coming into the breaker panel).

BGE got into a decades-long argument here in Maryland with PEPCO over who was responsible for maintaining/upgrading underground wiring that was going on 40+ years old and, for a long time, we experienced frequent brownouts, blackouts, but only when it got very cold, or very hot, or very wet or, very dry or windy (really). Sometimes we’d lose power for DAYS during ice storms or one particular derecho (wind) storm in JULY about 15 years ago.

I’ve since bought military surplus backup generators. 

We also got power OVERvoltages - as high as 135 VAC - which eventually took out several appliances, a TV and a breaker panel we had to replace; insurance covered, I never found out whether the insurance co was able to subrogate and get reimbursed by BGE for the cost.

On a lark, after the underground wires were finally replaced, I measured power levels day to day. They varied by about 5% around 120 VAC, but mostly stayed at/around 123 VAC with occasional peaks to 125, lows to 118.

These days I use the Cyberpower “conditioner”/UPS to maintain an even 118 VAC as I use some older equipment designed to run on 115 VAC; set any lower and the UPS sets off alarms.

220-221 ... whatever it takes ...

I don’t see an answer to your question so far. What the utility is required to provide and what will damage your equipment are two different things. And I don’t really know the answer. Probably the answer is well below any voltage that you will see. You didn’t say what type of gear you have. But solid state gear will probably work fine and eventually trip off. Most ss gear will rectify your AC to DC, and regulate it to a much lower voltage. If the regulator is good, it will never know the voltage is low. Tube gear usually is ok with lower voltages but not always. If you have a good tube amp I’d ask the designer/builder.

You’ll more likely hear poor performance than damage your gear. These are my educated guesses though. I don’t know all the architecture and design features of your gear.

You might find support equipment that runs off of 120VAC to not operate correctly, perhaps a remote volume control or a display system.

What does damage equipment is high current. power = current x voltage So a piece of equipment, such as an inductive motor, that needs constant power, will pull more current at a lower voltage. Refrigerators are the classic home load that can be damaged during a brownout. Still, 109 volts should be fine. Air conditioner motors can fail too. The theme here is motors that pull a significant load. If you ever have a brownout--you can see the lights dimming, run, don’t walk to unplug your refrigerator and large loads.

Turntables have a small motor. Unless someone know knows more about turntables speaks up knowledgably, you might want to not use your turntable at low voltages. but I’d give it 95%+ chance it will be fine at 109V.

If you do want to buy a power supply to fix the problem, PA Audio regnerative power plants are probably the best. I set the output voltage on mine and it controls it +/- 0.1 volts. The specs say it can operate down to 90 volts. Note that this is low enough that you could use it to run 120V equipment in Japan (100 V standard).

Jerry

@blackbag20 

Good one from Mr. Mom

Quick and funny... not hurting anyone. A good way to start my day.

Robert53, Three things come to mind.

First, in published measurements made on high-powered amplifiers, some testing lab mains sag and do not provide sufficiently high voltage and power to supply the amplifier with 120 VAC. Krell tests comes to mind. The test reports usually forgive the amplifier for not meeting specified output in these cases. From that I gather that brownouts/sags will compromise power amplifier performance.

Second, these days, in the northeast, mid Atlantic, and surely other parts of the US, the high temperatures lead to high demand for electricity, and mains power quality suffers. Being a close lietener and a "fixed income person", I fear erratic power fluctuations, which will compromise system performance and could possibly do severe damage an amplifier.

To navigate those concerns, I listen until about noon most days, and then shut down until after dark. This is in contrast to my preferred MO, which is to rotate an amplifier into my system and leave it powered-up for one or two months.

A few years ago, I tried a Monster power regulator of some kind. Specs of that regulator were above the power my Mc7270 would draw. After using the regulator for about a month (and playing at about 70dB through reasonably efficient speakers), around 5:30 on a weekday, a power cap failed and an energetic fire started in my living room. Sure, the caps were old, but I'm left to wonder whether that regulator played a role in what happened.

Gene from Audioholics has a video on the effect of low voltages on power amplifiers. If the voltage gets low enough it will affect the output of your amplifier if you play it loud. IIRC he was talking about voltages of around 100 volts or even lower.

Amir from ASR has also discussed the effect of low voltages in a video of a power conditioner (I believe it was the review of the PSA P12). He stated that audio gear is designed to operate on a wide voltage range and that it is very unlikely that you could damage your gear from operating it at low voltages. If the voltage gets too low the unit will malfunction or shut down but it would be rare for any damage to occur.

I want to thank everyone for the valuable information. It's cooler today and the power is back to 120 volts. I use a Shunyata Venom PS8 with the plug in power filter, but I'm going to look into a Furman or Tripp Lite unit. 

I’ll also check out the PS Audio unit. 

Thank again.

Thanks again.

The older PS Audio Power Plant Premier works well with my 60 watt/ch tube integrated amp. It worked well with my previous SS 80 watt/ch amp as well. Dynamics is not compromised. Everything is significantly better than without it or with older Furman voltage stabilizer.

I would not, however, recommend this particular model. There were many reported reliability issues. I got lucky, my unit has been trouble free since new, that's more than a decade. And PS Audio stopped repairing this model, I think.