Super Newb grounding question number 5993439

[drfrink24]

I'm building an active crossover, the PS inputs are labeled AC and GND (GND meaning Neutral I guess?). Nowhere on them is anything labeled a chassis ground.

So, what is the proper way to safely hook this up? Even if I ground the chassis to the Earth ground on my 3 prong plug, the PCB is still technically floating, right?

I know this is super-newb, but, my gainclone kit had provisions for H, N and chassis ground.

[leadbelly]

No instructions?

If you are indeed hooking up the mains to the PCB (transformer is on the PCB), they yes, you would hook up hot to "AC" and neutral to "GND". Make sure that you haven't missed a pad, i.e. the lettering "AC" is actually sitting near 2 adjacent pads and is meant to identify both. I also would check with a meter to make sure that the "GND" pad you speak of is isolated from the DC power and signal ground pads on the board, and of course put a fuse and switch in the loop. Neutral is technically the "grounded conductor" in the world of electrical codes, but usually is never referred to in that manner by technical writers because of potential confusion with "ground", which sounds like it might be your case. Assuming that is all correct you can ground the DC power and signal grounds to the chassis along with the AC earth, preferable at a single point.

[Tim__x]

I wouldn't hook it up to the mains yet. What crossover is this? Do you have a schematic? It might want something along the lines of 18vac.

[drfrink24]

Originally posted by Tim__x
I wouldn't hook it up to the mains yet. What crossover is this? Do you have a schematic? It might want something along the lines of 18vac.

I haven't assembled anything yet. Its Micheal Price's KIT281 2-way crossover, which can be used for just about any 2 way application.

http://web.mit.edu/pricem/www/activexo/

Schematic:

http://web.mit.edu/pricem/www/active...atic-onech.gif


PCB:
Attached pic below


I emailed Michael, he clarified things:

It is a standard "center tap" transformer connection. The key is to connect
opposite ends of the two secondaries together to form one winding twice as
long, with twice the voltage; and the point in the middle is connected to
ground. That way the two signals appearing at the "AC" input terminals on
the PCB are each 22V in magnitude, but out of phase. The voltage across the
two terminals is 44VAC. That's how it produces the +/-30V unregulated DC
supply (60V total, but with ground halfway between the two supplies). This
ground can be connected to chassis, mains earth, etc.

[drfrink24]

This really helped:

22V --- 22V
H------N-H------N
AC-----GND-----AC

[leadbelly]

I'm happy you're all set.

Originally posted by drfrink24
This really helped:

22V --- 22V
H------N-H------N
AC-----GND-----AC

You should avoid calling one side of the secondary the "N" or "neutral". Technically, it is incorrect, and it is the source of your confusion in this case, and may come back to haunt you in the future. Mr. Price has done it properly and identified them as "AC".