Hissing sound from amp, unsure if guitar is at fault.

Apologies in advance if this is the wrong area for this post.

I removed the string ground from my Squier Tele, as I don't want my body acting as ground while I'm touching the strings (the noise generated by the Tele is tolerable). Nothing else has been modified on the guitar. Since then, I've found out my house has electrical outlets that are grounded to their respective outlet boxes, and not to a central ground wire.

I have noticed that if I touch a metal part of my amp (a Fender Frontman 15W practice dealie), all excess noise stops. It also stops, as expected, if I touch the control panel on the Tele.

My question to you folks is this: could this be a result of the house's grounding, or would it indicate a ground loop or something within my amp, or possibly guitar? My theory is that something is "leaking" to the metal portions of the amplifier, but I'm not entirely sure and I don't want to open the amp unless I have to (I am entirely competent w/ a soldering iron, but it's a lot of hassle if nothing is wrong).

Thanks!