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5 3-500z box

C

cman

Member
Jun 30, 2011
5
0
11
Hello everybody im a new man here(y).well i guess i will get the ball rolling with what should be a interesting topic.I have a 5 3-500z box that was converted from a heath kit it has a 90 amp filament transformer.I want to run it in my mobile i am getting a 250amp alternator.My tech seemed to have disappeared so now im kind of in the dark.I would greatly appreciate any help i can get so lets get going.
 

cman said:
Hello everybody im a new man here(y).well i guess i will get the ball rolling with what should be a interesting topic.I have a 5 3-500z box that was converted from a heath kit it has a 90 amp filament transformer.I want to run it in my mobile i am getting a 250amp alternator.My tech seemed to have disappeared so now im kind of in the dark.I would greatly appreciate any help i can get so lets get going.
Click to expand...

sounds like fun (y)
if anyone else here has any ideas on what you want to ask on doing, im sure the right people will help you out. 73s!
 
cman said:
Hello everybody im a new man here(y).well i guess i will get the ball rolling with what should be a interesting topic.I have a 5 3-500z box that was converted from a heath kit it has a 90 amp filament transformer.I want to run it in my mobile i am getting a 250amp alternator.My tech seemed to have disappeared so now im kind of in the dark.I would greatly appreciate any help i can get so lets get going.
Click to expand...

Let me bust your bubble as gently as possible; It ain't gonna work!

In my 30+ years of experience, I have seen large glass Transmitting (3-500Zs and, 4-1000) Tubes used in mobile service and, the owner/users end up throwing away a bunch of money and they are never satisfied with the outcome.

For whatever reason, the high wattage that they put out is as weak a water and, a transistor amplifier will cut right through 3-500Z/4-1000 carrier. I know, I tried it years ago on the Shoot-Out line.

Look at the "Mechanics" of making that thing run in the mobile; Filament current of 90 amps at 5.0 volts, takes a lot of BIG resistors to drop the 13.6 volts down to 5.0 volts to light the tubes. 3-500Z tubes should be run with a center-tapped AC filament transformer with the CT being the cathode return/bias circuit. How are you going to do that properly? With a big inverter that imposes an audio whine on the "AC" output.

Are you really going to try to generate the B+ needed (3000 volts at 3 amps minimum?) via a stack of 3 phased alternators and transformers on your Stroker 318 engine or, do you have a 454 cu. in motor?

However, there is nothing wrong with Champagne Dreams on a Beer budget!

YMMV.

One more thing, "If you need more than one tube to get the power output that you want, you need a bigger tube". Sell the 5-Tuber and think about a single "Steel Toob" amplifier

.
 
paws264 said:
Let me bust your bubble as gently as possible; It ain't gonna work!

In my 30+ years of experience, I have seen large glass Transmitting (3-500Zs and, 4-1000) Tubes used in mobile service and, the owner/users end up throwing away a bunch of money and they are never satisfied with the outcome.

For whatever reason, the high wattage that they put out is as weak a water and, a transistor amplifier will cut right through 3-500Z/4-1000 carrier. I know, I tried it years ago on the Shoot-Out line.

Look at the "Mechanics" of making that thing run in the mobile; Filament current of 90 amps at 5.0 volts, takes a lot of BIG resistors to drop the 13.6 volts down to 5.0 volts to light the tubes. 3-500Z tubes should be run with a center-tapped AC filament transformer with the CT being the cathode return/bias circuit. How are you going to do that properly? With a big inverter that imposes an audio whine on the "AC" output.

Are you really going to try to generate the B+ needed (3000 volts at 3 amps minimum?) via a stack of 3 phased alternators and transformers on your Stroker 318 engine or, do you have a 454 cu. in motor?

However, there is nothing wrong with Champagne Dreams on a Beer budget!

YMMV.

One more thing, "If you need more than one tube to get the power output that you want, you need a bigger tube". Sell the 5-Tuber and think about a single "Steel Toob" amplifier

.
Click to expand...

wow.. you are so wrong.

Filament. If he had 5 then why not take 2 tubes out or put 1 more tube in? Run 3 filaments in series and bam 14.25 volts will light them within spec. run two parallel banks of 3 tubes each with each banks filaments in series.
problem solved.

Bias, none needed to cut the tube off in stby because the HV is ony on when keyed
problem solved

get one extra alternator maybe say 165 amp+ and remove the rectifiers so you have a 3 phase output, connect that to a 3 phase mobile transformer with six rectifiers after it and add a cap and bam you got HV. B- to chassis ground, amp chassis to chassis grnd, b+ to anodes.
problem solved.

put a relay in box so when it keys up it aplies vehicle v 14.25vdc to the brushes of the alt (full field) bam.. you got HV
problem solved

when you want more volts on the plate rev the motor, when you want less volts let it ease back down.

he could do this with MINIMAL EFFORT.... come on man, guys been doing this for decades...
 
lol...Linearone you are the man... I was scratching my head for a min when he said it could not be done... I was also dumfounded at the part about weak wattage. There are guys were i live that key AC mobiles all day long and they have no problems.. except for when I key my 2 tube 3cx3000 box into my beam talking DX.
 
The Heath Kit SB220 was a two tube amp,i know i have one.It has two 500z tube in it.It will run 110v or 220v...Why run that much mlb...i never run over 500wts mbl,its a waste.73s de JW
 
thank you for the advice linearone.I get tired of guys talking about going to key downs all over the country and getting on line .why cant i enjoy the fun????????????I guess there will always be haters.
 
Years ago, couple decades anyway, heard tell of a mobile amplifier called a "Crabpot" came out of Louisiana, had 6 3-500Z for a final and drive it with whatever you want.

Described exactly like this post so YES it has been done for a long long time nothing new about this set up, plan, simple, and highly effective.

\QUOTE=linearone;299247]wow.. you are so wrong.

Filament. If he had 5 then why not take 2 tubes out or put 1 more tube in? Run 3 filaments in series and bam 14.25 volts will light them within spec. run two parallel banks of 3 tubes each with each banks filaments in series.
problem solved.

Bias, none needed to cut the tube off in stby because the HV is ony on when keyed
problem solved

get one extra alternator maybe say 165 amp+ and remove the rectifiers so you have a 3 phase output, connect that to a 3 phase mobile transformer with six rectifiers after it and add a cap and bam you got HV. B- to chassis ground, amp chassis to chassis grnd, b+ to anodes.
problem solved.

put a relay in box so when it keys up it aplies vehicle v 14.25vdc to the brushes of the alt (full field) bam.. you got HV
problem solved

when you want more volts on the plate rev the motor, when you want less volts let it ease back down.

he could do this with MINIMAL EFFORT.... come on man, guys been doing this for decades...[/QUOTE]
 
Supporting those glass tubes, supplying them with what they require to operate is the biggy. If you think that would be easy/simple, think again. Just wanna do it so you can say you did? Hey, go to it! If there are simpler/cheaper ways of doing it, then why bother? Up to you and your wallet...
- 'Doc
 
W5LZ said:
Supporting those glass tubes, supplying them with what they require to operate is the biggy. If you think that would be easy/simple, think again. Just wanna do it so you can say you did? Hey, go to it! If there are simpler/cheaper ways of doing it, then why bother? Up to you and your wallet...
- 'Doc
Click to expand...

?

so why cant it be done again? I explained how it would be done.
 
Yes, it can be done, I never said it couldn't.
The point is, if it isn't the most -practical- way, and it isn't considering the typical power sources available with a mobile, why not do it an easier, more efficient way? The "KISS" principal really does work for the best most times. (Or maybe that ought'a be "KI$$"??)
The only suggestion I'd make is to get ready to 'up-grade' the vehicle's charging system!
- 'Doc
 

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