Why was the 8' 85w killed off?

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Why was the 8' 85w killed off?

Post by Tom » Sat Mar 26, 2011 12:29 am

Does anyone know why the 8' 85w tubes and fittings were phased out? It was conceived by Thorn as an effecient alternative to the original 125w way back in the early 60s but was only suited to starterless gear which was either quickstart or SRS. I think the confusion of 3 different wattages may have been one reason after the 100w tubes came out in the 70s. However, there were some fantastic fittings made for these tubes such as the Atlas Atlantic which I'm sure any survivors would still be alive and lighting! All I can say is fair play to Transtar (thanks supersix_94 for bringing this to our attention!) who have gone to the trouble of developing a magnetic ballast with electronic start for this tube! :D

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Re: Why was the 8' 85w killed off?

Post by SuperSix » Sat Mar 26, 2011 9:29 am

I think in the end is boils down to efficacy and cost again like it does with everything. Thorn couldn't develop an energy saver for the 8' 85W since is only ran on starterless gear, the 8' 100W is a bit more efficient than the 85W and will run on cheaper ballast and starter switch. Upon switch-on, the starter closes and preheats the tube's cathode filaments. Upon opening, the magnetic field within the ballast collapses, causing a voltage pulse which strikes the tube. This is often repeated twice or more, causing the distinctive blinking at startup.">switchstart gear which is probably the reason.

It never seemed so popular in the first place though, the 65w took over from the 80W completely and new installations of 80W fittings pretty much ceased yet installations of 125W carried on until the 100W came out. It's a real shame they weren't more popular!

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Re: Why was the 8' 85w killed off?

Post by Kev » Sat Mar 26, 2011 9:48 pm

I believe that the 85W tubes are still available through SLI but who knows how reliable they are?? In 2005 i re-lamped a pound stretcher that had 2X85W SRS and Quickstart Atlas Atlantics, a lot of the quickstart ballasts were dead which was a shame but i did get supplied about 25 boxes of Philips MCFE Pro/840 85W tubes which when they worked were good!!

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