Operating our amps at 110 volts (& strange volume changes)

[syscokid]

In our 3 bedroom house, I just discovered that all the wall sockets in bedroom 2 & 3, which are on the same circuit breaker, are putting out only 110 volts. Every other wall socket and lighting fixture in the house is putting out 120 volts.

Since most of the time I'm operating my amps, including my precious Metro 50w Plexi, in bedroom 2...I was wondering what could be the possible side effects when doing this.

I've been noticing some intermittent volume changes after my Metro is thoroughly warmed up. I'm not sure what is causing the volume changes, but I did have to readjust the bias. Last week I checked and set the bias at 35ma's. When I checked today, they drifted down to 33-34. After I plugged the Metro into a wall socket running at 120v, the bias read about 39ma's.

I thought I heard the volume drop a bit again after awhile (then it came back up), but it only did it once in the 20 minutes that I was testing the amp, since plugging into the 120v. Then again, it could have been my imagination getting the best of me...

Any suggestions and info?

[Structo]

How old is your house?

Does it have grounded outlets?

Yes, wall voltage can definitely affect the amp.

The power transformer is built for 120v so if you only give it 110v, then all the secondary voltages will be lower.

The one I would worry about is the heater voltage.
If it is too low it can damage the cathodes.

What's weird is that you say it is low in just a couple rooms.

That would lead me to believe that you have a bad connection somewhere, possibly in a light fixture or junction box.
A lot of times in residential wiring, they use the over head light fixtures to join the wall outlets to the circuit.
Typically this is done with wire nuts, the little colored plastic things that is on the ends of the wires in the box.

Another thing that can happen in older homes is where the actual wire is attached to the receptacle.
On older homes these were screw terminals and over the years they can loosen or become oxidized, creating a poor connection.
Some newer receptacles have push in terminals where the wire is simply stripped a little bit and then pushed into the holes on the receptacle.

So I would possibly pull the overhead light fixture from the ceiling and tighten all the wire nuts that are in there. It can be a real jumble of wire in there.
Of course, be sure to turn off the breaker for that room.
Leave the light on and have somebody yell at you when you turn the right breaker off.
Also check the wall outlets to be sure the wires are fitted tightly.

I prefer the screw type terminals and most receptacles have both the screw and push in type.
You need to poke a paper clip into the release hole in order to pull the wire out.
Strip off a 1/2" of insulation then wrap it around the screw so when you tighten it clockwise the wire is going the right way and tighten it up good.

If you don't feel like converting them all to screw type connections, just pull the receptacle out a ways and push the wires better into the back of the socket so a new fresh connection is made.

Hopefully your home does not have aluminum wiring which is a whole other nightmare to deal with.
Hope this helps.

[syscokid]

Thanks Tom. The house is 23 years old, and does have grounded outlets. Within the last 2 hours, I was fortunate to talk to a friend of mine who happens to be an electrician. He said it could be something simple as a loose screw...so I need to check the wired connections to all the wall receptacles in those two rooms. He also let be known that he doesn't care for the push-in connections, and that the screw-down type are more reliable. But, he asked me to first start with the connections at the circuit breaker panel. Sure enough, at the circuit breaker that controls those 2 rooms, the inserted hot wire was really toasted at the switch. I was able to cut the wire back, about 1 1/2", to where the insulation was in good condition, and reinsert the wire.........

And now we have 120v at all those outlets......

And...and...and no more volume drops after 1 hour of making crazy guitar noises...

What I still wonder about, is what could have caused that wire to heat up to the point of toasting the insulation of the wire, and also deforming some of the plastic on the circuit breaker. I'll have to keep a close eye on it and try to replace it sooner than later.

[syscokid]

OK...I know this turned out to be a wierd post...and here's the Head on the Nail (and a couple glasses of wine):

Before I checked the household voltages, I thought my new issue with my first build (Metro 50 watt Plexi), was either bad soldering, or one of any tubes going funky, or the bias resistor failing, or the OT is failing...or who knows what else? I'm pretty new to this, but it's still pretty rewarding when I find out that I just learned something...

[Structo]

Glad you found the problem.

What could have happened is when the house was built, the electrician forgot to tighten that one wire.
Maybe someone called to him or some other distraction.

Or the first owner or subsequent owner had changed or modified the wiring and had loosened that screw on the breaker for some reason and never tightened it.

Then as the years rolled on the wire was getting oxidized because of the poor connection probable arcing.

I am surprised however that your friend did not have you check the overhead light boxes, since that is usually where the wires from the wall outlets are connected for each room.

You can probably just loosen two screws after you get the light cover off and tighten the wire nuts.

Sometimes the Romex (house wiring) can get a nick in the wire from stripping the insulation off the end and it can actually fracture the wire there, but since it is inside the wire nut it still makes good enough connection to work, albeit at a lower voltage.

But you probably saved over $100 by finding the problem at the breaker box and fixing that bad wire.