TNT 250 vs a TS 250, both/ var power ?.

[9C1Driver]

Years ago I ran a MagnaForce 200 which came in a redish colored case, the TnT 250 is the replacement. After the TnT line came out the MagnaForce line was discontinued. I do know this, I have had many Texas Stars over the years that had slight SWR issues. The impedance match is ballpark at best. Anything built by X-Force was rock solid with no SWR issues amp on or amp off.

The TnT250 is class B and built like a sherman tank. While I like both amplifiers the TnT is the better built better performing amplifier.

 

[psycho]

North Texas...not to be rude but... you are ABSOLUTELY WRONG here! The texas star is absolutely biased... hence the voltage divider that supplies idle current to the base of the RF power transistors. Most amplifiers use a simple wirewound resistor and a diode to accomplish this. Most are non regulated either. The problem with the setup I just mentioned is that a bias source needs to be a low impedance high current source. That is why with no drive applied they appear to work but wrong value devices cause the bias to go negative often seen in magnaforce / tnt and other style amps. The texas star at least uses a voltage divider which remains more stable. Anyone who can read a schematic or knows what they are looking at on a board layout can clearly see all texas star amps except the modv use this circuit and are therefore biased. Anyways..not going to argue but check out the board or schematic for yourself.

Also this garbage in garbage out "fad" is a bit ridiculous. While it is true that a distorted signal in will result in a distored waveform out...I have heard it incorrectly said that a radio that produces splatter will cause an amplifer to amplify the splatter and the harmonis too....not true!!! What gain do you think a broadband amplifier that uses HF devices will have up at 54mhz or even higher on the 3rd harmonic? Zilch! Nada! None! Not to mention that the circuit isn't tuned or designed for it.

Now that is not to say that a transmitter distorting on negative peaks and clipping won't cause the amplified signal to be a mess too...it will. But if we are to teach and to share information we must make sure we are explaining it correctly.

"Garbage in garbage out" is a fad? That is a ridiculous statement. If operators run their amps properly, you would never know the difference between a Texas Star and a TNT.
If Messenger ever went into full production with their complete line of amps, Texas Star would go out of business.

 

[AudioShockwav]

If Messenger ever went into full production with their complete line of amps, Texas Star would go out of business.

Unfortunately the Guy building Messenger had a stroke, and sold the business to Billy Ward, Billy Passed this last year without getting it going again.
I do not know if his son is even interested in continuing the building, but some of the amps showed up on Ebay, they were complete minus the transistors and in the listing it said no more would be built.
I am sure it will not be long before someone pirates the name and starts building cheap class c knockoff`s.


73
Jeff

 

[psycho]

Unfortunately the Guy building Messenger had a stroke, and sold the business to Billy Ward, Billy Passed this last year without getting it going again.
I do not know if his son is even interested in continuing the building, but some of the amps showed up on Ebay, they were complete minus the transistors and in the listing it said no more would be built.
I am sure it will not be long before some pirates the name and starts building cheap class c knockoff`s.


73
Jeff

There is an unmarked 350 without the 2 2879s on Ebay right now!


Messenger Amplifier | eBay

 

[North Texas Mudduck]

North Texas...not to be rude but... you are ABSOLUTELY WRONG here! The texas star is absolutely biased... hence the voltage divider that supplies idle current to the base of the RF power transistors. Most amplifiers use a simple wirewound resistor and a diode to accomplish this. Most are non regulated either. The problem with the setup I just mentioned is that a bias source needs to be a low impedance high current source. That is why with no drive applied they appear to work but wrong value devices cause the bias to go negative often seen in magnaforce / tnt and other style amps. The texas star at least uses a voltage divider which remains more stable. Anyone who can read a schematic or knows what they are looking at on a board layout can clearly see all texas star amps except the modv use this circuit and are therefore biased. Anyways..not going to argue but check out the board or schematic for yourself.

Also this garbage in garbage out "fad" is a bit ridiculous. While it is true that a distorted signal in will result in a distored waveform out...I have heard it incorrectly said that a radio that produces splatter will cause an amplifer to amplify the splatter and the harmonis too....not true!!! What gain do you think a broadband amplifier that uses HF devices will have up at 54mhz or even higher on the 3rd harmonic? Zilch! Nada! None! Not to mention that the circuit isn't tuned or designed for it.

Now that is not to say that a transmitter distorting on negative peaks and clipping won't cause the amplified signal to be a mess too...it will. But if we are to teach and to share information we must make sure we are explaining it correctly.

hmmm????
i was trying to say that a Texas Star box is not a AB as they claim it to be

 

[Mudfoot]

Is Billy's son into radio at all?

 

[MudDuck442]

Ok let's clarify... yes, Texas Star amps with the exception of the ModV are AB biased. I would be more than happy to start a new thread and post a picture of the schematic with the bias circuit circled using photoshop and also put up a spec sheet showing idle current required for AB operation.

As far as the garbage in garbage out "fad"... I called it that because it is often as I *previously stated* not explained correctly. Yes, a clipped signal in will result in a clipped signal out, but an amplifier does not amplify harmonics, at least not when we are talking about a broad band HF amplifier using the design methods 99.9% of all CB amplifiers use.

Make sense now??

 

[AudioShockwav]

Is Billy's son into radio at all?

I do not know for sure, I do know one of the family members, I will try to send her a message and see.
They were devastated by the loss and at the time I did not want to bring up radio stuff.


73
Jeff

 

[North Texas Mudduck]

if the radio has a spur or spike when you turn that amp on it will amplify that spike or spur as well

 

[Grogan]

Another Vote for the texas star. I have the 350HDV and would say to add a fan to the 250 I have mine sitting on a 4" axial fan low speed. I also have an RM KL-203 I have been trying out on SSB with a 2950dx turned down to 2 watts, And I get great reports and it seems to run pretty clean. over 100 watts AND makes skip shooting A brease