[Amps] Re: 811 Plate Color/other tube color/Damage

[rlm]

On Monday, November 3, 2003, at 04:51  PM, Pat Barthelow wrote:

> rlm Said:
>
>> ***  The problem is not with the 811A grids, it's melting holes in 
>> the 811A plates/anodes due to the increased velocity of electrons 
>> because Collins Radio used more than the rated anode V.
>
> There's a great picture of a pair of 4-400As  producing lots of power 
> (modulators) at:
>
>  http://hawkins.pair.com/atcitynj/atcity14b.jpg
>
> Can you guys give an opinion as to whether these 4-400As or other 
> tubes with this plate color are within their long life operating > range?

***  4-400As/4-250As/3-500Zs and the like show color because such tubes 
cool themselves mainly by radiation.
...