Can the sound of SS amp deteriorate over time??

Yes it can, for a varity of reasons. The main resevoir caps(the large cans) in most high end amps are charged thru a very low series resistance. The current surge upon turn on present a "shock" to the cap, and over time causes excessive DC leakage. This can easily be measured, however after 10 yrs of, say daily cycling, it becomes prudent to replace them in order to avoid the possibility of the cap shorting. Many quality amp provide a means to adjust output transistor idle bias and DC offset. This needs to be periodicly checked and/or adjusted. Semiconductor chactoristics change over time and temperature cycling. I can provide assistance in most cases, if you are interested.

Eldartford: In effect, the systems that you discussed are tempurature and environment controlled without being exposed to transient power variations. As such, i would expect most any reasonably built product to last a long time and work properly when called upon to do so.

Outside of those conditions and getting back to the real world, where thermal swings and power transients exist on a regular basis, i'll stick by what my past experiences have shown me. Sean
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Sean I agree with your assessment. The heat factor of constantly going hot to cold (when equipment is turned off) to cold to hot(when equipment is turned on) is stressfull to the components in your equipment. Dormant stage on stereo equipment is alot better than powering up equipment from an off state. Yes good ventilation is essential and will prolong the life of your components.

Sean...The Navy systems see frequent turn on/off power transients, (for tests and drills) but these do not seem to have the bad effect which some folk expect. Perhaps this is because thermal transients are avoided. Incadessent light bulbs are the classic example of something that doesn't like being turned on and off, but electronics are not light bulbs.

I want to thank everyone who responded and provided advice and technical knowledge. Based on what I have read, especially regarding possible capacitor "aging" and "leakage", that it may be time to sell the amp and keep the tube pre-amp. I only need 75-100 RMS and prefer to have a smaller chasis amp that is not painful to lift and easy to move. At the same time, I want to also improve the sound not only by acquiring a newer amp, but one that also sounds better. I would be open to a tube power amp if I could find a unit that is at least 75RMS and whose bass is not mushy or poorly defined, especially since I will be using a tube pre-amp....Any advice on used amps, tube or SS will be welcomed. I can spend approx. $800-1000. Thanks again, Jim