Is there an average life span for a preamp?


I have a 6 year old Adcom GFP-750 preamp that has been used for about 12,000 hours already. Is there a certain point in hours or years when I can expect something to fail? This particular preamp has a passive option which I like and use currently. When used pasively I would thing that it should last forever.Please let me know what experiences you have had. Thanks.

Joe
jjarocki

Showing 4 responses by atmasphere

The main limitation is the life of the filter capacitors in the power supply. These days the half life of them is about 20 years (IOW- in 20 years half of them will have failed).

Of course many units will run longer than that but its a safe bet that if the filter caps are changed out they will sound instantly better!
Filter capacitors will hold up better if they continue to get used on a regular basis. However they will still degrade. Any piece that is over 20 years old should be considered suspect. It may well still work, but that is not the same as saying that it is working as well as it should.
Kijanki, that sounds about right to me. However as a side hobby I like to restore vintage analog synthesizers. Its pretty well universally accepted amongst those who do such work that the filter caps in the power supply should be among the first things to be changed during a restoration. Of course, many analog synths can be a few years older- some are from the late 1960s. But my Prophet 5 (http://www.vintagesynth.com/sci/p5.php) is from the 80s and there was no question that new filter caps helped it out- it sounded better and was far less sensitive to line voltage after that!
Kijanki, there may be something I'm missing but I would not expect much change to the output impedance with most amplifiers or preamps on account of the condition of the filter caps. In every case I have seen if the caps are ailing, replacement universally has the unit sounding more musical.

No speaker is so sensitive to damping factor such that you would be able to hear a difference between 4000 and say 200. The damping factor does not play much of a role with any speaker unless it falls below 20 or so. But as you say, some speakers *prefer* the damping of the amp to be lower.