Pre Amp Help

Hi guys. I am wondering if it is worth the switch to a dedicated pre-amp or a pre-amp/tuner. I currently use my Onkyo Integra A/V receiver as the pre-amp/tuner. I have an Arcam 8SE hdcd/cd player, an Adcom GFA-555II amp, and KEF Reference 103/4 loudspeakers. I use Audioquest interconnects and solid Audioquest bi-wire speaker cables. The Integra receiver is better than most, with a pre-out (obviously), and gold-plated rca connections for the cd, pre-amp out, etc. I like the receiver because of the nifty remote, display etc, but I'm wondering if I'm compromising sound quality. There is presently a reasonable B&K pre-amp/tuner on ebay, as well as an Adcom GTP-500. Any strong opinions??
You're asking a question that has objective and subjective answers. Objectively, there's no doubt that separates will offer better performance. However, I think you're going to have to step higher up the audio chain than Adcom and B&K to have gear obviously superior to your Onkyo reciever. If and when you upgrade source and speakers, you'll also hear greater differences in amplification upgrades. As to whether it is "worth the switch," well that's the subjective part. Only you know your priorities about where disposable income is best spent.
Borrow something from another local audionut and use that to help you decide.

Photon's comments make good sense, and without getting into specific brands etc., I'd guess that replacing the Adcom would make a surprising amount of difference.

How efficient are the KEFs & have ever tried a tube amp or pre? Cheers,
Definately go with the B&K PT3 preamp/tuner. I once had one hooked up to a McCormack amp with excellent results.
If your Integra has Audyssey room correction, then there's another aspect to consider. The other posters are considering "electronic" aspects. To me the main issue is the "acoustic" aspect. No matter how good your electronics are they have to perform in a room and it's that aspect that AV room correction systems are way ahead of all but a few audio products. So if you have a good room correction system and a normal living space, then you'll likely be going backwards by switching to an audio preamp. I don't know how long it's going to take for the high end audio manufacturers to address room acoustics.
Well, I bought the Adcom GTP-500 tuner, because I ended up with a winning bid of $120.00 on ebay (with original box, remote and manual). Figured I couldn't go wrong at that price, and should be able to sell the Integra for more. The Integra is a decent A/V receiver, but my thought is that it is also full of electronics that I don't need, such as the "Home Theater" 6.1 surround sound circuitry, the internal DAC, and the various electronics dedicated to various digital effects, such as "Concert Hall", "Dolby", "Theater", etc. The Integra is also geared to multi-zone/multi-room use, and I'm guessing there is unnecessary circuitry there as well. My (uneducated) reasoning is that the Adcom pre-amp/tuner was designed for 2-channel (audiophile, more or less) listening, and thus would have fewer and higher quality components, geared to that purpose. Also, the Adcom was made in the U.S., which I automatically assume (???) means better quality than the Malasyian-made (ughh)Integra. I've always heard the more direct the path, the better for the audio signal; I guess the ears will be the judge. Someone tell me I did the right thing...