Max AM RMS Output With Texas Star DX500V?

[skiman1]

What would be the max AM RMS output I could run with a less "swingy" radio with a Texas Star DX500V?

I'm picking up a Yaesu FT-891 and not only do they do a 5w minimum carrier on AM, they really have no swing, perhaps a 1-to-2 ratio vs what one would normally use like my 148 with a 1-to-4 ratio.

If I would need to run it the typical 125w carrier out, I would still need to use the dial a watt circuit, or an inline attenuator to pad the input.

I also realize too that if I run the typical 100-125w deadkey out vs pumping it up to say 200w out, it probably won't make much difference at the other end of the QSO and just cause undo wear and tear on the amp.

I really don't plan to use the 891/DX500 combo much on AM BUT, figure I would ask folks in the know just in case I want to occasionally without issue and what the proper/best practice use would be.

Thanks!

 

[Wire Weasel]

Seems you have answered your own question already ...... you don't want to take the dead key on this amp past 100W. And you're not going to get maximum swing out this amp using that radio.

 

[skiman1]

Thanks, that's what I kinda figured. Also I've heard those famed Dial A Watt potentiometers fail pretty often since they are rated at 2w, is this correct? If that's the case and since stuck with a 5w minimum AM carrier I will use a Zetagi RP2 power reducer and not use the Dial A Watt.

 

[groundwire]

And i guarantee 5w input drive into the texas star will put it way over the 100w output carrier you want to get (25w max output per transistor). Texas star amps are very low drive boxes.

 

[skiman1]

And i guarantee 5w input drive into the texas star will put it way over the 100w output carrier you want to get (25w max output per transistor). Texas star amps are very low drive boxes.

Yep, well aware, and why I would use an attenuator. The Zegati box does a good job, 1/2 or 1/4 power reduction.

 

[Big Kahuna]

You'd be better off just putting a cheap AM CB that has higher PEP in line to use with the DX 500

 

[AudioShockwav]

No more than 100 watt dead key out of the 500.

73
Jeff

 

[9C1Driver]

It really sounds like that combo will run hot, not have much peak wattage, and in a short time will burn up the dial a watt control. That's a loose loose loose situation right there.

 

[AudioShockwav]

The Texas Star Amps were designed in the single final radio days.
Back when some radios struggled to make 4 watts.
I see guys on Facebook groups running high power radios into these and then a week later they ask why the amp let out the smoke.
It's a real sticking point when some one says
" my Davemade 4 pill will take 80 watts drive, your Texas Star has the same pills in it, it will be fine........"

Poof

73
Jeff

 

[Crusher]

I believe the potentiometer in those Texas Stars are actually 1W I believe. I have a couple here somewhere. A 2W won’t fit. Keep it around 25-35w per pill max for carrier out of 500. Get a fan kit for that 500 or you’ll be frying bacon in no time.

 

[S&W357]

I have two Texas Star DX500 V amps. The potentiometer stays all the way to the left and I do not push the Green Button Cool Breeze blows up on the bottom side.

 

[AudioShockwav]

I have two Texas Star DX500 V amps. The potentiometer stays all the way to the left and I do not push the Green Button Cool Breeze blows up on the bottom side.

The one I use in my pickup has the power and delay on as I am on SSB 85% of the time.
ALC and AM/FM set inside radio.
Don't use variable.
Big fan on heatsink.
They are a good easy 300/350 watt SSB amp with a fan, on stock set up and that's how I look at them.
Had it a few years now, works fine for what I need at that level.

73
Jeff