The Sylvanias I recommend are significantly different than those that you have tried. But, please do some more research into the Modwright players and preamps, and you'll comments here and on AudioCircle from several users who have installed Sylvania GB-5687. Two local audiophile buddies who have systems vastly different from mine both use Sylvania 5687 tubes in their Modwright Sony 999ES Signature Platinum players. One likes the Sylvania GB-5687 and the other likes the Sylvania WA5687. For $20/pair, you have very little to invest to try the WA5687.
03-13-07: Foster_9
I've tried the stock Tung Sol's replaced them with the Raytheons then GE 7044's, then tried a second set of Tung Sol's given to me by Dan then back to the Raytheons's so I have tube rolled.
You can't tell me that the synergy present between the front end and the rest of your system isn't going to affect the end product (sound) with all of your cd's, the well recorded and the poorly recorded.True. However, what comes from the source component is the most critical. What's missing from the source will always be missing. Even the Modwright has information either missing or colored differently from other digital sources I have owned. It's a matter of preference.
Overall, I think the synergy thing is a matter of trial and error, and some luck. Unless you happen to find another audiophile with precisely the same electronics, speakers, wire, AC and room, you will not be able to assume their recommendation will translate to your system. That's a point well made by Arthur, and I agree with him completely. It's one reason I am recommending starting will a smaller expenditure since you already own a world class digital source, and one that fits into many systems regardless of their varying components and speaker systems.
It takes a strong working knowledge of voltage, gain and impedance matching to put together a "synergistic" system. Many of us don't have the working knowledge to do this properly, and that's where the trial and error enters the picture. If along the way we come across someone who knows this stuff in and out, like Alex Peychev did when I owned my APL Denon 3910 (and as Dan Wright does), then their help can be immeasurable in solving problems. Perhaps if you contacted Dan Wright, he might have a suggestion about adjusting the output voltage of your Modwright to better match your system.
Finally, if your Reimer loudspeakers are anything like the excellent Grand Tetons I heard, they are very revealing in the upper mids and highs, and will not help to ameliorate what you find objectionable in any of your poorly recorded CDs (or vinyl LPs, or computer music files). There are speakers that can be revealing and true to well recorded material while also being a little forgiving to bad recordings. You may not be able to hear the tympanist scratch behind his ear, though.
Best of luck on your quest.