Electronic 400w ballasts are too expensive for me. I am finding 400w MH ballasts on ebay for close to $50, such as http://cgi.ebay.com/400-watt-MH-Grow-Light...1742.m153.l1262 and http://cgi.ebay.com/Used-400-Watt-Metal-Ha...1QQcmdZViewItem

Are there any real advantages that e-ballasts have over these ones? I am aware that a transformer that size will make noise, but how much? And in the case of the one, encased in an aluminum casing inside a wooden box, would you even be able to hear it?

Another ballast discussion that might be relevant: http://www.lumenlab.com/forums/index.php?s...st&p=281508

Ballast Reference Chart, General info on bulb/ballast compatibility

Best Bulbs Chart, Good choices in 150w, 250w, and 400w

Personally, I'd recommend staying away from the "football" style lamps as they are difficult to adapt a reflector to. The LL 65K T15 400W Lamp costs the same as that one and is much kinder to a reflector adaptation.

"1 - 400 watt METAL HALIDE Capacitor"

Sounds like the person selling hasn't a clue about these kits.

A capacitor should be given a value in (MicroFarads most commonly) and a voltage (normally 250v or 440v).

You want to check out the ballast datasheet and make sure you are getting a capacitor to give you a Power factor (cos(Phi)) of as close to 1 as possible.

Just to be fair, I was reading through a post of brainchild's and he stated that an electronic ballast uses 40% less energy than a magnetic ballast.

I'd love to read that post myself, oh google search ninja.

Google: site:lumenlab.com +"electronic ballast" "less energy"

Here's a page that states electronic ballasts: Use 25-30% less energy and produces more light.

The first link is a good buy, has all you need without all the crap that the second one has although the shipping on the second one is free. The first one is a m59 probe ballast and a m59 or (e) bulb has its own starter so it does not need a starter

For a first build and low budget it has good bang for your buck. They last forever and rarely have problems works well with the ll400w se bulb or for that matter the DE LL bulb.

For a PJ that is not going to be used as the main part of the everyday use or if it is less than 6 hours a day it will do fine. If you are planning on using it as your main TV/entertainment system then you may want to rethink using a e-ballast.