Okay -- that makes sense. On the back of this one it lists the max at 5 amps -- but the numbers don't line up quite like yours. It lists 120VA, 60Hz, 5 amps, maximum all stacked on top of one another -- I need to do some reading to learn how the math works. I'll have to check my previous amp for interest.
I think that the wall plug will be the place to roll up my sleeves. I should be able to make the hardware store trip by the weekend.
@120VA, and assuming you're on 120V grid electricity, the unit itself should draw about 1 Amp.
120VA / 120 V = 1 Amp
The 5 Amps maximum, is the max amount of current it can handle which is the sum of its own power needs, plus any electrical devices powered through it.
Imagine having five of this particular amp. According to that 5 Amp max number and the fact that each draws 1 Amp, you could theoretically daisy-chain four more, one plugged into the next, off the outlet on the back of the first. If you were to add a sixth, you would be increasing the load by 120VA, or 1 Amp, which would then overload the original amplifier by 1 Amp, probably tripping it's fuse/internal protection somewhere.
Your amplifier, which by itself only draws 1 Amp, is pulling roughly the same amount of current as two 60W incandescent light bulbs* - that's not really all that much.
* Yes light bulbs are a resistive load, and powering the amplifier on probably acts at least a little inductive while it charges up its capacitors thus drawing a bit more than that 1 Amp for a sec, but complicates the math more than it needs to be for the numbers we're working with.
All said and done, as long as you're sure you're not overloading the house circuit that your amplifier, equipment, and lights all share, it's probably fine that you get a quick dim of the lights as you power up the amplifier and nothing to really be concerned about.
Are your light bulbs regular incandescent? If so, you might consider switching to LED bulbs - you'd probably never see the dimming on power-up, and use less electricity to boot.