Originally Posted by Erich H
Normally with the knob/tube wiring that you have they recommended not going over a 15 amp fuse. Yours look like someone installed 20 amp fuses which might not be the best idea.
Back when that wiring was installed, they didn't figure on the types of electrical needs we use today and that can cause issues.
The more power you pull through those lines, the hotter they get. Their insulation is not very good either. The reason you see 'most' of the wiring separated was to cut down on heat issues. It was recommended that they stay at least 3" apart at all times until those wires entered the fixture. And many times they came into the fixture at opposite ends of the fixture as well.
Going by past photos, it looked like the previous owners may have done some "handy man" type of fixes with the wiring and THAT'S where the main worry comes in. Any spicing must be put into junction boxes. If you ever do any insulating work to cut down on noise, you should NOT put insulation around those wires because they weren't designed to be covered up, which keeps the heat held inside. It's a significant fire hazard, especially if there's been bad splicing, wrong fuse upgrades, or the old insulation is in bad shape (which is almost always is).
One of your photos in this thread shows 2 wires touching and going through the floor. That's not the best thing, especially if you start pulling some decent power through those wires and they heat up.
I really hope you don't put both those amps on the same line. Also, if the 20 amp fuse blows, remember that it really should only be a 15 to start with. So please don't just get a larger fuse to keep it from blowing, that can be dangerous with that type of wiring. Your best bet (until you do some decent electric work) is to make sure your amps are on totally different lines. Going by the wiring, that's still not ideal, but certainly better.And I know you don't want to hear this, but I really am trying to help.
Please, please, please look very close for plaster cracks in the ceiling or walls on a regular basis. I have a 100 yr old home with the same type of plaster/lathe work. I would never subject it to extreme bass without some serious worries. My audio stuff is all in my basement, which was completely redone with double drywall and new electric.
That type of plaster work is simply not going to withstand the vibrations of serious bass. It's design just won't allow for constant vibrations. The plaster WILL separate from the lathe board. Maybe not immediately, but eventually it will fail.
I don't want to worry you, I just want to make sure you know this because I'm worried.
About 8 yrs ago one of my buddies had a brother out of work. He was a painter and needed some money, so I let him do some odds and end painting in my home just to help him out. I was gone for the weekend and he was going to paint a bedroom. I noticed a crack in the ceiling plaster and a very slight sag. I told him to skip painting the ceiling because I wanted to go over it with drywall.
I get home and he didn't listen and tried painting that ceiling! He'd been standing on the floor pushing a roller back and forth on the 9' ceilings. Obviously that light sag and tiny crack were being pushed up and down as he went over it with the roller. Yeh, a 6'x6' section came crashing down. He said he was very lucky to move back towards the door way as it fell. He broke a finger and the plaster crushed his tiny step ladder and his tools. He apologized for trying to do the work and said he was lucky not to be standing directly under it.
So please keep this in mind, that plaster is VERY heavy. Picture someone dropping the equivalent weight of maybe 1.5 inches of mdf board on your head from 9' up. I see the kids in your pictures and it really does worry me.
Seriously man, I don't want to sound like I'm pissing in your bowl of Wheaties here, I'm not. Just know that I'd worry if you put two 15" subwoffers in that house, let alone what you're doing. And I'm not talking about just that room you're in, but the entire house. It might be cool to brag that the subwoofers brought down the house, but not if there's a person sitting underneath when it comes down ya know.
Either way, good luck.