Sorry if I came off as abrasive yesterday... just about everything I was working on that could go wrong did. The bulbs posted on e-bay are rated for 10,000 hours at 14v A.C. by their manufacturer. As a general rule, when a bulb is fed D.C. at its rated voltage, it is expected to last half as long. The bulbs are military quality. All of the info you need is in the e-bay auction.
http://cgi.ebay.com/Yamaha-CS-80-CS80-Preset-Incandescent-Bulbs-/320677774366 I did the only test that I could with them without actually running them for 5,000 hours D.C. This test was fun. I found an equation stating that: "The life of a miniature lamp is inversely proportional to the 12th power of the applied voltage." So I figured, well, why not reverse the equation for longevity and cook em! Plugging into the above equation, I needed about 20.5 volts A.C. to get the things to burn out after 1% of their rated life. I hooked up my PSU and the samples that I had left in parallel. After 3 days and a few hours they were all done. (100 hours was the goal) I'm sure that there are other variables I didn't account for, but it was a fun test.
Setting the fun aside, I've sold 4 sets so far and haven't received a complaint or even heard of a bulb burning out. Only one e-bay individual has left me feedback.
I think they are reliable. I bought them from a very reputable manufacturer, am following their usage instructions, and did as much homework as I could.
Personally, I think that it is best to replace all of them. After talking with a few folks, plus hearing heard horror stories of buttons melting and bleaching (probably from the wrong replacements), it doesn't seem like a bad idea. Furthermore, the originals are probably at the end of their life anyway. I also work on mixing consoles and it's not uncommon to see half of the bulbs burned out on a desk that hasn't been maintained since the 80's.
http://launch.groups.yahoo.com/group/yamahacs80/message/2035 I don't see how the originals could melt or bleach but there are a few similar sized bulbs out there that consume WAAYYY more current than the originals and run a lot hotter as well as brighter. My bulbs consume a third less current than the originals, run a lot cooler than the originals, and have the same lumen output as the originals.
I hope that this answers your question.
-Mike
--- In yamahacs80@yahoogroups.com, Fernando Zarone <fernandozarone@...> wrote:
>
> Mike,
> sincerely ) would buy the bulbs, but would like to know:
> have they been tested for long time? i mean, are they reliable in the long run?
> Is it convenient to replace all of them , although the original are still working?
>
> Last, how much do a complete set cost?
> To Italy-
>