What is the lowest voltage acceptable ?

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.