I also feel that providing your SS equipment with purified electricity provided by a good AC line conditioner and good power chords can't hurt. Like drinking pure water? *** |
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 |
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. |
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. |
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. |
Sean...In the field of ballistic missile guidance systems (lots of very complex and precise solid state electronics) we have rather extensive experience with continuous operation and with on/off operation. (The Air Force operates continuously while the Navy operates on/off). Navy systems are commonly deployed without problems for six to ten years, whereas Air Force systems last a much shorter time (which I can't tell). Believe me, the Navy has also looked very closely at possible accuracy benefits of continuous operation, and it is not significant. However, it is important that the Navy systems opearate in a "Dormant" mode when "off", where heaters distributed throughout the system maintain temperatures very close to those that exist during operation. |
Porziob: Thanks for clearing that up for me. I, my annnually calibrated test equipment ( HP spectrum analyzer, tracking generator, AF & RF signal generators, Tek scopes, etc... )and the experiences of the mass majority of my customers must all be mistaken. I guess that i'll have to start denying the differences that the customers experience and what i can measure, based on your above testimony.
Qdrone: It is my personal belief that leaving equipment on causes less stress than power cycling it up and down on a regular basis. That is, so long as their is more than adequate ventilation for such and "dust bunnies" that can accumulate both on and in the gear are addressed on a somewhat regular basis. Not only that, but i think that most gear sounds better too. Obviously, this is just my personal opinion, so take it for what it is worth. Sean
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I've left my modified Adcom on for 15+ years and I've heard no deteriation in the sound.As someone said the design and how well you take care of your equipment comes into play. I also feel that providing your SS equipment with purified electricity provided by a good AC line conditioner and good power chords can't hurt. |
Short of bench testing an amp to determine if it meets spec, there is no way to tell for sure. Many, who consider measurements verboten, foolishly waste time & $ with ZERO improvement. |
Yes, electrical products can and do shift operating parameters over an extended period of time, especially if tempurature swings are involved. Sometimes, a simple alignment is all that is needed, sometimes parts need to be replaced and then an alignment will solve the problems. It all depends on the original design, how well that design was implimented, the environment of the gear ( in terms of ventilation and exposure to dust / airborne debris ) and the operating patterns that it has to deal with.
I get some units that come into work after 30 years that work and look like new. I get some other units that are two years old and look / work like they should be put out of their misery. As such, even a poor design can last a long time if it is babied and a robust unit can be falling apart if thoroughly abused. Most units are somewhere in the middle and therefore don't need a lot in order to bring them back into spec. That's why companies like Bryston can give the warranties that they do. Sean
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....and so does your hearing. |
The sound of all gear will deteriorate over enough time... |
Bdgregory and Soulbrass are correct. Electrolytic Capacitors do dry out eventually, reducing their effectivness. I would imagine decrease in sound quality would be the first to go, followed by eventual failure. Electrolytics have a conducting liquid inside, sort of like a so-called 'dry' cell battery, but the capacitor liquid is less viscous than a battery. |
Some companies recommend re-capping them after 10-15 years. As electrolytics age the amp will become "thin" they say.
I'm not sure why this isn't a consistent practice though, unless it's design related. |
Companies such as Naim Audio recommend that capacitors be replaced every 8-10 years. It is a regimen adhered to by legions of Naimophiles. |
As you purchase better & better ancilary components, a point is reached where the ancilary components become superior & the older components faults become evident. Nothing is actually wrong, but maybe that point has been reached. |
Many solidstate amps will need to have their transistors replaced.This was a problem on some of the early Krell amps,their transistors would "leak" although they tested fine.Same with the NRG Control amps,though that problem was due to under-heat-sinking the driver transistors.
Hpoefully the devices you need are still in-stock. |
Assuming proper ventilation & not being maxed out power wise 24/7, no reason you couldn`t get 30 yrs. or more. |
