Using a 6KD6 in lieu of a 6JS6

[Robert Grant]

I've seen many books and internet sources that suggest that the 6KD6 may be used as a substitute for type 6JS6 (as well as -A, -B, -C - but that the 6JS6 is not a sub for a 6KD6).

Seeing that my raster is a little lacking in width, that the HV seems to be low, and that the present 6JS6C looks "ugly" around the getter, I went in search of a 6JS6 before trying to restore the set (granted, many other things could be causing the HO to be weak,

but the HOT is a prime suspect).

As you may have guessed, I got a really good deal on what looks like a NOS 6KD6 at a hamfest.

Looking further, I notice there are differences between the 6KD6 and the 6JS6 series. Notably greater heater current (2.85A for the 6KD6 vs. only 2.25 for the 6JS6). Granted, the set is parallel-string filament, but could the extra 600mA tax the power transformer or anything else in the circuit?

The 6KD6 also has almost twice the input capacitance of the 6JS6.

BTW, the set in question is a Zenith 24MC32, Photofact 769-4

[ctc17]

The 6KD6 will work fine in your zenith. I use them in mine. The plate cap is smaller on the KD6 so you have to crimp the metal tabs in a bit.

[Robert Grant]

Thanks for the info.

This means I have a new tube for every tube in this set except one - the 21FJP22 (and it is somewhat newer than the set and already shows signs of life).

Amazing how many of the tubes in my set are original (or, at least Zenith-branded with mid-1965 date codes).