I just noticed in the online manual that the 990 needs 120 volts, plus or minus 3 volts, to operate correctly.

According to my Monster power 2600, it is registering 110 volts. Actually, the lights on my 2600 are NOT lighting up at 120. So I suppose it could be up at 117, 118 or 119 volts.

I will have to call Scott in the morning, as the manual also says to call if you think you may not be at the required 120, plus or minus 3.

You don't mention whether your 990 is malfunctioning in any way. If it's working normally, what does it matter what the actual voltage is?

I dont have it yet. I was looking thru the manual online however, and I noticed the information. Usually, the claim that it is 110 or 120 volts is vaguely mentioned, as opposed to 240 volts.

I just though it was strange that is was specifically pointed out that it needs 120, plus or minus 3, volts, to run correctly.

I thought a lot of electronics worked down to 110 volts.

120V and 110V are often used interchangeably to mean the same thing (residential 120V with a tendency to sag to 110V), much like 480V and 460V are often considered "the same" (HVAC manufacturers often submit their gear at 460V, which sometimes raises questions from the electrical engineers sizing switches, disconnects, or wire to that equipment from a 480V service). Scott could tell you for certain, but I'd suspect that the 990 would actually tolerate more voltage variation than 117V to 123V without operational problems.

Gonk is correct. The power company sends 240V into your house across 2 phases. It is really closer to 208V. This is then split in the middle to make your ground / neutral giving you 120V on each phase. This is really closer to 110V.
This creation of a service ground / neutral at your electrical panel is why you see your circuits grounded on the same bar (sometimes).

This is also why you get much better noise performance (less possibility of ground hum)by running a dedicated circuit for your stereo. The neutral noise from other things in your house (lights, computers, fridge compressor,air conditioner) run back to the panel (and subsequently the ground there) instead of through you amplifier.

Long story short... You should not have any problems with your 990.

Thanks guys. I do have a dedicated 20 amp circuit which feeds all of my gear, even though they run on seperate outlets.

Everything is plugged into either a Monster Powerbar 2100 (Sony XBR, sub, PS2, Wii, DVD player) or a Monster Power 2600 II (everything else) for some type of protection and filtering.

Some claim better performance is obtained from an amp if it is plugged ddirectly into the outlet, but I would rather have piece of mind of protection (lightning, spikes, etc...)

A 120/208 system and a 120/220 volt system are different.
As a rule of electrical thumb, most electrical equipment is made to accept a +/- of 10% of the rated voltage..
As time goes on we are starting to see more consumer equipment rated at a +/- of 5% though. With this swing it is cheaper to manufacture equipment.
Jim

I thought electric service was 120/240, possibly dropping to 110/220 - 2-phase, with the higher voltage always exactly 2x the lower. I don't understand how Hullguy's "120/208" and "120/220" are possible.

You have 2 different systems of electricity. A 120/208 volt system is a 3 phase system. This means you have 3 wires wired together in a "Wye" or star fashion. The voltage reading between these wires is 208 volts. A 4th wire is attached to the center of the wye or star. This is where the 120 volts comes from. The formula is 208V/1.73= 120 volts.

A 120/240v system is derived from a transformer having a center tap on the 240 volt coil. This gives you your 1/2, or 120 volts.
Jim