Grounding Questions

[RookieRecurve]

I have a question regarding grounding of my setup.  As some of you know, I scavenged a stepdown transformer from an old Dell powered computer speaker (120 to 17), and added a full-bridge rectifier to change that to DC.  Finally, that will be regulated down to 16vdc using a buck converter.  This will then feed the amp (once I assemble it), and feed an external speaker.  The current transformer does not have a grounding plug, a fuse, or a power switch. The enclosure that I am using is plastic.  I am planning to add a power switch and an inline fuse, but am unsure about a ground.  I know from working with tube amps, that the voltages in there are lethal, and therefore grounding protects people from high voltages.  In the case of this amp, after the first stage of the transformer, the voltages are around 17VAC.  Is grounding necessary here?  Is the lack of a metal enclosure going to introduce a bunch of noise?  Will the lack of an earth-ground make this amp noisy?

[Loudthud]

Is grounding necessary here?  Is the lack of a metal enclosure going to introduce a bunch of noise?  Will the lack of an earth-ground make this amp noisy?

Yes, the ground side of your Voltage output should be connected to the Mains Safety Ground. Without that ground, a guitar will pickup hum and you may get a mild shock or tingle when you touch something that is grounded (like a microphone) while holding the guitar.