Q: lifespan of JJ ECC99 tubes

[Irakli]

Irakli, about how many hours of use are you talking in an average year? At this operating point I would not expect them to last much over 1000 hrs and conceivably much less, they're being run very hard indeed. The 5687 may be a reasonable alternative, but will require some wiring changes to accommodate, and might not last any longer..

Thanks Kevin. I would say 600-700 hours per year is a good estimate.
I agree that tubes in this application are running very hard (actually I like to run tubes hard).
I bit the bullet and just ordered NOS Raytheon CK5687 on ebay. The seller says they are made in 60's, so I guess the quality of these tubes are very good.
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices.

We shall see how long the Raytheon tubes will last.

 

[Irakli]

Don't dis Soviet military production tubes, many of them are very good.

IMHO, The quality of any Soviet military (or otherwise) production tubes was inferior to that of the american ones of the same period.
"American" in this context="Made in USA"

I am not saying that Soviet tubes are bad, just they are lesser quality that their American analogs.

 

[vinylkid58]

IMHO, The quality of any Soviet military (or otherwise) production tubes was inferior to that of the american ones of the same period.
"American" in this context="Made in USA"

I don't remember saying anything about them being better than "Made in USA".

jeff

 

[mace1337]

I would try 6N6P in there, but you have to rewire the heaters.