Preamplifier that supports 3D movie

If you have a dual HDMI output BD player, you don't need to upgrade yr current preamp.

Just send one HDMI to the preamp and a second one direct to the display.

The cheapest I have seen in my region (Asia) is the Pioneer BDP-LX55 which retails for less than US$400 bucks. Probably cheaper in the US. The Samsung equivalent is not available here.

I use an Oppo 95.

You can try AVSForums.com They also have an online sales department.

The main problem is that active 3D projectors require as much brightness as possible

Have a look at the Dalite HP screen. If you can fit your projector in the right area (i.e. zero offset pointing directly at the centre of the screen), it should give you around 2.4 gain.

The downside is that higher gain screens tend to have a smaller viewing cone, so the gain tapers off when you are off axis.

Which projector are you using?

Most projectors don't meet their "claimed" lumens rating when calibrated properly. I think the best (like JVC) could do 600-800 lumens (depending on zoom etc), and most were doing 300-500.

With 3D, some projectors "cheat" a little by using the brightest (non calibrated) mode for 3D, then use the tint in the 3D glasses to compensate a little.

But whatever lumens you have gets halved immediately with active 3D (since only one "eye" is active at any one time) and then that gets chopped further to account for switching between L an R images.

Be prepared to lose up to 70% of the lumens. That's why a lot of 3D projector owners prefer high gain screens.

ps if you can live with a 2 projector set up, I'd recommend an old JVC RS35/25/15/HD250 (preowned) for ultimate black/contrast and then get an Optoma HD33/3300 for 3D duties. This is IMHO the best of both worlds.

Most LCD/SXRD/DILA projectors aren't as well cut out for 3D (ghosting is still noticeable).

There are DLP projectors with lens shift as well. But these tend to be more expensive.

I use my DILA with zero offset on a shelf (lens aimed at the centre of the screen).

I would position the DLP with a fixed offset above or below the screen (ceiling mount)