Adding to the brief tube perspective of this thread...

Although my profession is in live theater and am frequently a sound technician,I do not have a technical background in sound engineering or electronics. Regarding the 990, I can only add my transformative experience especially concerning the "dry, cool, analytical, and fatiguing" sound. Personally I do not find the 990 to be fatiguing.

My young childhood was spent witnessing my father's hi-fi habit, with 2,000 vinyls, Audio Research pre/amp, and IMF transmission line speakers (talk about warm and full sound). Fortunately and unfortunately, my ear was tuned to fidelity very early on.

After I left home and paralleled with the growing technology of SS in the 80s/90s, all I could afford and easily available was SS.

Last year, I finally was able to move into the separates realm. I had a Sony STR-DA3000ES HT receiver which has an internal digital amp. Supposedly, a SS way of providing a warmer sound. To me the receiver sound was too laid back, flat, and with no midrange life.

When I changed to the 990/7125 combo, I immediately notice an improvement of the sound. Better presence, and as you state bensqsun "more resolution, more air and openness."

However, there was still something lacking when listening to music. I was enjoying what I was hearing but I was not immersed in it. This I refer to as the emotional connection. Technical jargon is not my specialty.

Pondering back to my tubular roots, I decided to research tube possibilities and came across tube buffers as a fairly inexpensive alternative to an amp. I purchased a Grant Fidelity tube buffer as an experiment.

I started with the buffer between the CDP and 990. I immediately noticed a difference. The sound was a more forward midrange, liquid highs, slightly tighter bass, and more warmth. Above all, there was an emotional connection to the sound. Whether this is correlated to "warmth" I don't know, probably a bit subjective. I do not qualify sonic characteristics like audio or wine critics. Simply, it was the first time in the evolution of my system, I really wanted to listen my entire music collection all at once. Finally sonic satisfaction.

Maybe Altec can shed some light on the descriptive sonic differences between tubes and SS.

Thus, my long winded suggestion would be to try a tube processor or buffer. If there is a local hi-fi store, try a tube cd player. The added benefit to tubes is the "rolling" to customize for your enjoyment.

BTW--In my system, I do not hear any distortion with the buffer in line. Quite the contrary, the sound is just as clean as with out the buffer.

So, this may be an inexpensive alternative to try. Switching out for another SS pre/pro is not the only alternative.

Really bang for the buck, the 990 is a solid unit. I'm sure there is tweaking that is needed in a lot of systems to find the ideal synergy. I am pretty content without having upgraded the firmware yet.

Good luck bensqsun. Keep us informed on your progress.

AK