5kW Mobile tube or solid-state?

[Shockwave]

Had a 3000, now ive got a 6000. Thinking of changing to two 3000s. My daily driver is working on getting a 3 tube 3-500z

I had excellent results with a 6,000 as a base. Although, I've heard from one questionable source that they may not hold up as well in Mobile use as a result of vibrations. I've also seen one that had a migrating grid wire problem. A brief conversation with the car battery and jumper cables across the filament and grid ring, quickly improved the tubes attitude. Have you seen any issues like this in the 6000 tube?

 

[linearone]

I had excellent results with a 6,000 as a base. Although, I've heard from one questionable source that they may not hold up as well in Mobile use as a result of vibrations. I've also seen one that had a migrating grid wire problem. A brief conversation with the car battery and jumper cables across the filament and grid ring, quickly improved the tubes attitude. Have you seen any issues like this in the 6000 tube?

Nahhhh its fine. The biggest issue with the 6000 is the higher plate v required.
The biggest benefit of the dual 3000 box is a simpler filament situation and slightly higher plate dissipation rating.

 

[linearone]

You are correct. The unloaded plate voltage will typically be much higher than the loaded plate voltage. You want to bring the RPMs up, only after the load is applied. The most critical part is when you unkey and remove the load. You want to be off of the throttle before you unkey the microphone otherwise the possibility of a large voltage Spike exists. Most of these systems are not voltage regulated and the ones that are, still experience what's called overshoot when the load is removed. That causes a brief voltage Spike which tends to take out rectifier diodes and capacitors. There are ways to avoid this like installing a large choke in the DC line however, the whole system is a bit of an inconvenience to operate.

Shhhh dont give all the secrets away...

But as far as inconvenience, i mean, its not as easy as a 2 pill but when you can see three ac alts make 80k plus its really puts power and alternator use into perspective. Just key the mic and rev a little. If each key is at a sightly different plate voltage, who cares? You see less watts, ok, so what? I used to key and unkey while driving around, not every key is full throttle comp mode. But even on one alt, you could key at idle and get a couple thousand watts... Its hard to beat.
You have to struggle to get a big dc box up and realistically all you have is a pile of little expensive fuses to worry about.

The thing that i like the most about ac boxes is that they are safer in my opinion. Seriously.
You dont have a pile of stored potential in a dc battery bank waiting to short or catch on fire. The power is present only when keyed. It goes away when un keyed. You have less weight in the truck, less wires, less gigantic cable, less connections, no vats of battery acid, honestly, its easier. In most vehicle if you can upgrade the stock alt and add one ac you can get 5-7kw

 

[Shockwave]

Shhhh dont give all the secrets away...

But as far as inconvenience, i mean, its not as easy as a 2 pill but when you can see three ac alts make 80k plus its really puts power and alternator use into perspective. Just key the mic and rev a little. If each key is at a sightly different plate voltage, who cares? You see less watts, ok, so what? I used to key and unkey while driving around, not every key is full throttle comp mode. But even on one alt, you could key at idle and get a couple thousand watts... Its hard to beat.
You have to struggle to get a big dc box up and realistically all you have is a pile of little expensive fuses to worry about.

The thing that i like the most about ac boxes is that they are safer in my opinion. Seriously.
You dont have a pile of stored potential in a dc battery bank waiting to short or catch on fire. The power is present only when keyed. It goes away when un keyed. You have less weight in the truck, less wires, less gigantic cable, less connections, no vats of battery acid, honestly, its easier. In most vehicle if you can upgrade the stock alt and add one ac you can get 5-7kw

I never understood why most DC people carry tons of batteries and keep that constant charging current, cooking the alternator. I've run up to 21 Toshiba's on one Leece Neville, without a single battery connected. All it took was a couple of electrolytic caps in parallel, to get close to a Farade and a regulator with a few modifications. One to start the field without a battery and the other to prevent voltage overshoot. Then is works almost like AC, right down to being able to get the same watts from each alternator, as you do with AC.

 

[Shockwave]

when you can see three ac alts make 80k plus its really puts power and alternator use into perspective.

It's been about 25 years since I've had any experience with an AC mobile however, assuming you're not exaggerating it would appear much has changed with these alternators since then. I remember struggling to get six or seven grand out of a 165-amp shortcase Leece Neville and 10 bushels out of a 200 amp large case was really pushing it.

Is that 80K peak and do you know which type of alternators were producing that? I am curious because if they have improved that much, it removes some of the limitations I was facing years ago, running DC with no batteries. Combined with the fact that capacitors have evolved into Super caps, this method may be more practical than it was in the past.

I just checked and found 48 volts with at least 100 amps, is a popular alternator size today. That has me thinking about what could be done with one modified alternator, one super capacitor, and something like four BLF188XRs... That could be a relatively economical 5kw mobile.

 

[linearone]

It's been about 25 years since I've had any experience with an AC mobile however, assuming you're not exaggerating it would appear much has changed with these alternators since then. I remember struggling to get six or seven grand out of a 165-amp shortcase Leece Neville and 10 bushels out of a 200 amp large case was really pushing it.

Is that 80K peak and do you know which type of alternators were producing that? I am curious because if they have improved that much, it removes some of the limitations I was facing years ago, running DC with no batteries. Combined with the fact that capacitors have evolved into Super caps, this method may be more practical than it was in the past.

I just checked and found 48 volts with at least 100 amps, is a popular alternator size today. That has me thinking about what could be done with one modified alternator, one super capacitor, and something like four BLF188XRs... That could be a relatively economical 5kw mobile.

Since everyone can just get 320a leeces now its not a thing plus guys run boost. Also contrary to popular opinion you can run more than one supply per alternator. Im also talking avg.

 

[Shockwave]

With respect to lighting the filament on the 6000 tube, I just noticed that they have regulated switch mode buck voltage converters available in ranges from 50 to 100 amps today. This would be ideal to provide efficiently regulated filament voltage from 12 volts. Some of these converters are advertised as having the isolation required to charge batteries, that are not in the same configuration as the negative grounded 12 volts feeding it. This allows the ability to float the directly heated cathode with respect to DC ground, so that it's easy to apply negative bias.