The preamp I use sounds dull, muddy and lifeless on the clean channel. What type of rack mounted FX unit would I need to buy to make it sound brighter?

Hmm.

A graphic or parametric EQ might help. Another option would be a sonic enhancer like the BBE or Behringer offerings.

However, if a Gainiac sounds lifeless and dull, I'd be looking at the sound from the guitar in the first place. EMG pickups are not exactly renowned for sparkly crystal tones when running through a clean sound. (I'm guessing that the active pups are EMGs... apologies if I'm making false assumptions.)

Yes the pickups are EMGs. I was reading a thread on some other forum last night and other people with active EMGs seem to be having problems with the clean sounds too.

Thanks, I will look out for an EQ on ebay. Does the EQ plug in to the patchbay or the preamp?

The EQ wants to be between your preamp and power amp.

If I recall, the Gainiac is mono and most of the EQ's you find on eBay will be stereo.
This means you'll only need to use one channel. You could however use one channel to EQ the guitar signal before the preamp and one channel to EQ the signal before the power amp.
You can have the EQ permanently wired in or run it through the patchbay and select it when you want. You could also run it through the patchbay using normalled connections - that way its permanently in the loop until you put a jackplug into the front of the patchbay.
(I'm assuming you understand about normalled, parallel and through connections on your patchbay)
Hope this helps

Thank you for replying BV. I did not realize the the gainiac II was mono. At the moment I have it plugged into a stereo power amp with y splitter leads. Do you think this could be causing the bad sound I'm experiencing.

I have decided to buy an EQ and the sonic sound enhancer which dragon mentioned.

Today I received the sonic exciter and the EQ I ordered. The EQ has made a huge difference and makes it sound at least 50% better. The sonic exciter adds a nice bit of spice to it too. I have not tried it with the ganiac II yet but I imagine it will sound awesome.

I'm finally happy with the sound for the first time since I changed to a rack setup. Just want to thank you guys for helping me sort it all out

Pics of it?

I will take a pic of it tomorrow.

Not really much of a rack, just low budget equipment but I got a start somewhere. I still have not painted the rack yet so it's basically just stacked on top of each other for now.

Sorry forgot all about this but better late than never!

What will you fill the other 2U with?

I have 3 compressors not in use, I could sell you one