6146 et al.

[Steve Harrison]

At 05:48 AM 1/6/99 PST, John Campbell wrote:
>Hi Gang...
>
>   It seems to me that the original design of the HW/SB series equipment
>was based upon the specs of the original 6146 (A) tube. I seem to
>remember reading a factory service bulletin that recommended the use of
>only 6146A tubes (at least for the SB-401).

And, At 07:23 PM 1/5/99 -0500, Edward Swynar wrote:

>As regards the 6146's, as far as I know, the aplha suffix denotes greater
>plate dissipation, in growing increments by letter, with the "W" version
>being "king of the hill" in this regard---

That may happen to be a coincidence, but perhaps not. The 6146W is supposed
to be a ruggedized version of the 6146B, able to withstand mobile vibration
and operation. There are subtle differences in the interelectrode
capacitances between all types such that some models of radios won't work
quite right with all 6146 types; i.e., there are sometimes problems
neutralizing one or more types. This also holds true for different
manufacturers. It's always best, if you don't have reliable info to the
contrary, to stick strictly to the type recommended by the radio
manufacturer or that is now working in your radio.

Thus, if you have a radio that works well with one manufacturer and type of
tube, your spares should include at least those particular types. You can
always try others, of course. But for spares, stock what you already know
works.

It is also recommended that spares be operated every few years for a few
hours to help prevent them from becoming more gassy. When you obtain a tube
intended for spares stocking, you should, of course, try it in the radio
immediately. Tubes do not have an infinite lifetime; they become gassy as
the seals slowly leak through the years. Operating them for a few hours
allows the getter element to "burn out" most of the gas.

73, Steve Ko0U/1

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