Low Voltage on Circuit


Just tested the Voltage coming out of my wall and it was 112.7 V. This is obviously too low to feed my 120V tube monoblocs and my tubed pre amp. For about a week when I turned on my equipment it would shut off after about 30 seconds of play. I stumbled for a few days trying to isolate the problem but kept running in circles. I then took a trip to get a multimeter and tested the juice from the wall. Please let me know how to fix this, preferably with an inexpensive step up transformer or other solution that can be done DIY for under $100. My associated equipment all on the same circuit is:

Rogue Audio Magnum M120 Monoblocs (120Watts)
DIY pre amp using 2 6SN7 tubes
EAD Ultradisk 2000 CDP

buckingham
117 volts is an exceptable voltage.

If you have all your gear plugged into one circuit this may cause the voltage to drop to an unexceptable level.

Try running three dedicated 20 amp circuits to your gear. Plug the amps into their own circuits. everything else into the remaining circuit.

You can test this theory by running extension cords from other rooms (Other circuits) over to your gear. Grab a circuit in the kitchen and one where you plug in your washing machine. Use these two circuits for your amps. Plug everything else into the wall outlet behind your gear. If everything stays on you need more dedicated power at your gear.
Glen, with no load on the circuit there is 115V, with all the equipment powered on it is 112.7V dipping to 110V sometimes. If I owned my own place I would surely use dedicated 20 amp circuits for each Monobloc and 15 amp for the sources. I am currently renting a room for 4 months in a house that was built in the 1940's. I've tested the voltage on the other circuits and it's the same as this room. This only started happening this week because of the high A/C usage in the area, so I am guessing the voltage is low to start with at the street even before it gets into the house. I will try the extension cord idea tomorrow but I foresee similar results as the voltage is the same. This only needs a temporary fix as I will only be in this room for another month until I move back to Waterloo in a newer house in a newer neighbourhood with a good power grid. Any ideas?
Buckingham, try measuring other outlets throughout the house. If they are all low, chances are that you will have to get the electric company in on this one. They may have a pole transformer that is going bad. It might be failing with the heavy load of air conditioners and 1.35 million fans running full tilt. If that is the case, running dedicated lines won't do a thing for you.

If the problem that you run into does fall into the hands of your local electric provider and they don't seem to be too eager to correct the problem, you can have what is called a "buck boost" transformer installed. These come in various voltages but the ones that i've seen were primarily rated for 12 volts. What this does is "stack" another 12 volts on top of the voltage that is already present on the line. This would take you up to almost 125 volts, which is a little high in my opinion. Then again, my voltage is pretty much rock solid at 123 volts and i've never had any problems. You may have to look around to see what is available in terms of buck boost transformers if this is the route that you have to go. Sean
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I've never suggested a PS Audio power plant but this may be the singular exception
Take a look at the ExactPower website for an interesting-looking solution that's not as monstrous as the big Power Plants, and won't add a transformer's resistance to the line. Never heard this product in action myself, though. Best of luck! :-(
Hey guys, thanks for the tips. Does most equiment have something in the power supply to compensate for low/high voltage? Is there some way to implement this externally?
OK, Now your talking, 115v is unexceptable. Call the power company and have them come out and take a reading. (This is free by the way) Tell them what your experiencing. Are the lights dimming or acting funny? You may need a new main service. If you have a cheep tester you may not be getting an acurate reading either.

If it is in fact 115v at the meter and you are not currently experiencing heat wave conditions, than they will take care of it. Most Power companies pride themselves at keeping the power right at 120/240. Or at least that is the case here in CA.
Glen, we are actually in the middle of a heat wave, which might explain the low voltage in the area. This problem only started happening when it started getting hot here in Toronto. I'm guessng it's because of the A/C usage in the area. Do you think the power company will look into this even in the middle of a heat wave? I'll give it a try.
I found this product for super cheap. It does voltage regulation, surge protection and some conditioning.
Here's another link for that voltage regulator. Is 5 amp and 600W output enough to feed the Rogue Monoblocs and my tubed pre?

http://www.tripplite.com/products/conditioners/specs/index.cfm?model=LS604
Being that you live in Canada I can't say for sure what to do. A simple call to the power company couldn't hurt for starters. During a heat wave demand goes up and voltage goes down. I'd check it again when it's cooler, try late at night if it cools off.

Good luck
Buckingham:
If it´s the power company´s fault or the particular house you´re in, try to check voltage at a neighbors house to see if the situation is the same (Dunno if that´s possible?)

Does the house has 240 feed with two phases?
Don´t know but might be a chance if the wiring is old that the house is on the low side phase which might make things worst....Have to ask the question and better if the power company guys pay you a visit
Good Luck
I know that the potential during summer months is for utility companies to "top off or somehow limit" the voltage to entire neighborhoods to save power for AC consumption across their grid.

This occurred in one of my buildings last summer. I had entire banks of battery back ups going crazy for a week.

Once the utility rep inspected, he fixed the problem by allowing more voltage within thirty minutes of diagnosing the problem.
5 amp, 600 watt is not enough. 15 amps might be minimum, 20+ is better, for wattage look on the rear panels or in the manuals of all your gear and add up the draw. 600 may be enough for the sources, but not for the power amps too.
I looked at the power consumption of the components in my tube based system.

The transport's rated consumption: 24 watts
The two tube dac's rated consumption: 24 watts
The all tube preamp's rated consumption: 26 watts
The 30 wpc tube power amp's rated consumption: 236 watts

Total power consumed at "full throttle": 310 watts

While your monoblocks are far more powerful than my little "antique", you MIGHT be able to get away with a 500 watt supply IF you turned things on gradually and never played the system very loud. Since this is strictly a temporary thing, it might be worth a shot.

The info that i sent you on that one piece states that it is actually good for 6-700 watts before the protection circuitry begins to clamp down, so that might offer a slight margin for error should you "goose the throttle" by mistake : )

The other alternative is to pick up an inexpensive but useable HT receiver from Best Buy / Circuit City. This would probably work under those conditions, give you something to tinker with for movies as a cheap secondary system while also giving you something to fall back on if your preamp or a power amp takes a dive. To me, this is a better solution than spending the money on the voltage regulator which might not work. Even if it does, when would you ever REALLY have the need for it once you move ??? Keep in mind that the more power that you pull from a regulator, the more the distortion goes up. Sean
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Hey Sean

I just bought the Tripp Lite LC 1800. It's a 15 amp voltage regulator/surge protector/noise remover. It should be here sometime next week. Hopefully it fixes my problems.
good luck and keep us posted. I'm sure that there are others in your situation. Some of them might not even know it : ) Sean
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HA HA HA... I'll have to break out the calculator for that one : ) While i can come up with a figure based on the factory ratings, who knows how accurate that is after some of the gear has been modified ? It's probably close enough to get in the ballpark though. I'll check and report back. Just don't call "Greenpeace" on me when i report the findings : ) Sean
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While looking at all of the components in that system, i found out that some of the custom pieces are not labeled for power draw. On some of the other stuff, such as the power supplies to run the various panels, i can't recall what was used. As such, i can't really come up with a grand total.

Since the amps are what draw the most juice, i figured that is what was most important. Some of these figures are based on calculations using the line voltage and fuse ratings on the individual amp. I had to do this since there was no total consumption figure listed on the chassis.

The two tweeter amps total 1600 watts of draw, the two mid amps total 2400 watts and the two woofer amps total 4800 watts. Add in the "whopping" FIVE watts ( !!! ) that my preamp draws and we come up with 8845 on just the backbone components. I'm sure that i would be well over 10,000 watts if everything would be factored in.

If you're wondering what "line level" components would add another 1200 watts of draw, i've got the electronic crossover, tuner, cassette, TT & vacuum pump, transport & dac and the four power supplies to run the mid and tweeter panels. As i've mentioned before, there is NO way to make this wiring nightmare look "pretty". The electrician that i had come in just kept shaking his head : ) Sean
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...and then, of course, you'd have to add in your other systems (how many of those did you say you have?)...I think I should start-up a small Enron-style company to corner the electricity market on your block... :-)
Hey guys,
Voltage went back up to 118V today and it turns out that that wasn't the problem. It seems to be the power amps themselves that are acting up. When I turn them on there is a rushing and popping noise that grows with time. It is worse on the left monobloc. The right monobloc has similar simptoms but milder. I have changed out the small tubes for some NOS to rule them out but haven't tested the large KT88 Driver tubes (4 per monobloc). I sure hope it isn't a cap or something bigger. Any ideas on what to test would be great. Thanks again for your help guys.
Although I was actually a little surprised to begin with that the voltage you reported would cause any problems, the fact that each of two monoblocks is acting up at the same time would tend to eliminate something like a parts failure - unless they both got zapped by a large power-line event that you didn't know about. Other possibility is that the tubes are growing too old together all around.

Conversely, are you absolutely sure that the problems originate in your amps at all? In a tube preamp, a single tube will often handle both channels. If you've got a tube pre and haven't ruled this out already, the symptoms could be worse in one channel than the other if a tube is going bad. If you need to, try running the amps with the preamp off, or better yet, with the amp inputs disconnected to rule out possible jack- or cable-related culprits. (Can you still cancel the order on that voltage regulator?) Gook luck!
Zaikesman,
your response came right after I figured out exactly what you hypothesized :) Looks like there is a bad tube in the pre amp. I should of known there was nothing wrong with the Rogue Monos, those things are indestructable. BTW the order for the regulator somehow didn't go through on the website, so that put a smile on my face. Thanks Zaikesman.
Glad it worked out for the better... Tubes - I love 'em, but they can really drive you nuts!