Preamp Suggestions??

As one poster mentioned, going to a tube pre will help, but the Adcom 555 needs to be cleaned up to gain some real benefit.
The 555 is fairly easy to work on. Unscrew the top cover.

You'll see teh blue power supply caps. Add some film and foil bypass caps to each of the main filter caps. Will make a large improvement in the sound quality.

then get a tube pre amp and you should have a system with will sound significantly better.

best of luck

Johnss: Your suggestion seems "sound" to me (pun intended). I hear the other commenters deride the Adcom amp, and I appreciate their suggestions (hey, I asked, didn't I), but I think the critcism is largely unwarranted. I'm not an audiophile per se, but I'm a fairly educated fellow and I've listened to A LOT of systems in my time. The set-up I have now is among the best I've heard. The combination of the Arcam HDCD (I have not played standard 14 bit CDs in it yet) and the KEF speakers create an open and distinctive soundstage. The mids are a bit bright or "harsh", but they are crystal clear, and the stereo separation and clarity is shocking. Voice reproduction from the 6-1/2" Uni-Q drivers is uncanny. The reason I went with the 200 wpc Adcom, however, is that I could get relatively little bass response from the KEFs. The Adcom took care of that. It is true that I have not listened to any quality tube gear. From the comments it seems tube gear is genuinely superior. Since I am generally happy with my equipment, though, I would like to try the tube preamp suggestion (I am also a little "cheap"). When you say "add some film and foil bypass caps" I know you are referring to capacitors, but I have no idea how to add them to the circuit board. I'm sure you solder them in somehow, but I think your suggestion may be over my head. Do you think the average tecnician from a local eletronics repair shop would likely know how to make these improvements?? Also, If I am going to try the tube preamp, is there a recommendation? Will I also need a tube tuner?? Thanks all!!

Hi, I would say that the power amp is the weak point. I am using an old Adcom GFP 1-A preamp with my custom tube power amplifiers.. Dont let the rich guys talk you down.. The Adcom is a decent preamp. I have a Conrad Johnson preamp and the Adcom is better, hands down. If you are interested in a nice stereo tube power amp let me know, I can custom build to order. It will definitely change the way you listen. What is the efficiency of you speakers?
Jim.

Preamps in the sub $500 range go quickly. You have to be ready to act quickly if you want to get a good deal.

I see a Rogue Metis in the classifieds right now for $450. This is a well regarded tube preamp that includes a phono section and remote control. It will add some warmth to your SS amp and be a nice foundation to build on. If I were in your shoes I'd jump on it. Live with it for a month and do back-to-back comparisons with your Adcom GTP-500II. That should give you plenty of time to hear the difference. There's a nice review of the Metis at 10 Audio

Will I also need a tube tuner??

I think you're referring to biasing, but maybe you literally mean a tuner. FWIW, tube preamps don't need to be biased, but tube amps do. Instructions are usually included with the unit.

If you like DIY kits, the Bottlehead Foreplay is unbeatable for $450. It's certainly not swanky looking, but the sound is what counts and you'll learn a lot by building it. Check out this forum:

best bang for the buck tube preamp?

If a kit isn't your idea of fun, there's a Foreplay in the classifieds right now for 450:

http://www.audiogon.com/cgi-bin/cls.pl?preatube&1224622962

Another suggestion is Dynaco Pas 3. This is well-regarded classic with a huge following. I see one in the classifieds right now :

http://www.audiogon.com/cgi-bin/cls.pl?preatube&1224699063