[Amps] 3-500z substitutes

[Steve Harrison]

The other nice thing about the original 3-500Z is almost-instantaneous
heating; no waiting two - three minutes before you can even tune up. And
then once you work the DX, you can turn the amp off. Of course, the
compromise is the much-higher filament power required while it is on
(105 watts vs. 25 - 35 watts).

And think of all the time, energy, drill bits, hole saws, and blood,
sweat and tears you'll save by just plugging in a new tube and fixing
whatever damage there is, instead of trying to retrofit a forced-air
blower, socket and chimney, working out a new filament supply, probly
new bias supply, etc. etc.. Then you wind up with a frankenstein that,
if you decide to resell it, nobody will want to buy.

'Tis a no-brainer, to me.

Steve, K0XP


On 10/30/2024 7:38 AM, jim.thom jim.thom at telus.net wrote:
> The 3CX-800A7 has a max anode V rating of just 2250 vdc.
>
> The AL-80A/B has 3100 vdc no load on it....and 2750 vdc loaded.....so you
> can scratch that tube off ur list. (3CX-800A7)
>
> The 3CX800U7 has a max anode V rating of just 1800 vdc.  Scratch that tube
> off your list.
>
> 3CX-400A7 has a max anode V rating of  2200 vdc. Scratch that tube as well.
>
> 3CX-400U7  rated for just  1500 vdc.  Scratch that tube.
>
> GI46B  rated for a max of  2 kvdc.  scratch that tube.
>
> I'm telling you, you are wasting your time.
>
> Just rebuild the amp, power supply, and whatever else is wrong with
> it.....and stuff a new 3-500Z into it....and be done with it.
>
> CTR engineering also sells a real compact output TR relay board ( that's
> correctly sequenced)..that has now been used successfully in a lot of
> different amps.  Quiet..and fast.  Comes in 12/24/120 vdc versions.
>
> https://www.ctrengineeringinc.com/relays/   $59.00
>
> Jim  VE7RF
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