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I discovered I have 2 quads of RCA 807 tubes. Adapters are easy to find.
Any issues to worry about when using in a Heathkit W5m ?
Thanks,
Ross
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The screen grid, of an 807, can not handle high B+ as can a KT66, and is likely to fail in a H-5 amp.
I agree that you shouldn't use the 807 because the plate voltage is too high for them over time and you can't lower the bias current and there is no reason to as that's a fabulous design..As Eli said the KT66s are speced for this amp but I actually prefer the 6L6gc RCA black plates overall in these amps.I like the Genelex reissue KT66s about as well so it's kind of hard to choose..Bottom line,I would buy a set Gen KT66 reissues or a set of 6L6gcs and be done with it.
A friend you get for nothing,an enemy has to be bought
while I agree staying with KT 66, Michael... the 807 can handle far more voltage on the plate than any KT66. I have Williamson circuit running in Triode with 420 volts on the plate... been running them that way with over 2000 hours on the same tubes. Tough as nails... 807... the tube that won the War. I believe they will handle 600 on the plate with 300 on the screen with aplomb.
The Mind has No Firewall~ U.S. Army War College.
Ken
I get what you are saying and yes,the 807s will handle a higher plate voltage provided you lower G2 so you don't exceed the plate dissipation of the tube.I was looking at it more of a practicality standpoint as opposed to making adapters or changing sockets.I also should have been more clear that the W5m is tethered to the UL circuit where we can't alter G2 to be able to run a higher plate voltage on the 807s.
A friend you get for nothing,an enemy has to be bought
"Any issues to worry about when using in a Heathkit W5m ?"
I woldn't use them, simply because of the exposed high voltage. 6L6GCs aren't that expensive.
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I don't know Sh*t from shinola about this tube/amp combination, but the one thing that comes up most of the time is whether the tubes heater current can be supplied. I'm sure there are others who can be more eloquent and specific about heater current compatibility.
Heater current is not a problem. The W5M schematic calls for KT66s as O/P tubes and the KT66 draws more heater current than other 6L6 family tubes draw.
Compare the 2 types' data sheets.
http://www.mif.pg.gda.pl/homepages/frank/sheets/084/k/KT66_GEC.pdf
http://www.mif.pg.gda.pl/homepages/frank/sheets/084/8/807.pdf
It looks like the KT66 is rated for a bit more plate dissipation. Installing 807s in a W5M should be OK, provided the amp is not pushed to its published limits.
Eli D.
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