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TEXAS STAR 1600 AS A BASE
- Thread starter TonyV225
- Start date
Keikiokalani has three days to think about his conduct here.
You're questioning because you don't know the answer, so consider no one here has called you names for that. RF Parts openly admits in their advertising that those $100+ "Red Dot" Toshiba's are lesser parts than the original ones without the dot. They had to change the insulator inside the red dot part. The red dot has less ability to transfer heat and breaks down at a lower voltage than the older part.
Going over 13.8 volts will force the the red dot part to work harder in both of the areas it is known to be weaker in, especially due to the bias circuit used in that amplifier. You could drive this with your Yaesu, assuming the amplifier has a decent input VSWR. However, in time you'll probably see the entire amplifier setup was not the best choice for your application with an HF rig in the base when you start needing to use your spare transistors as replacements.
I'm assuming when you say you have 16 red dot Toshiba's, there are 8 in the amp and you may have 8 new spares? If I were you, I wouldn't think twice about what to do here. Sell the amp, extra transistors and the 200 amp power supply to finance the purchase of a real HF base amplifier before you no longer have 8 new spares to sell. You should easily be able to buy something that uses tubes no smaller than 3-500Z's and enjoy a cleaner signal with more reliability and still have the ability to easily maintain it for many years to come.
This scenario has happened so many times in the past I felt compelled to explain the reasons better. It's simply the wrong approach. While there is a good deal of money tied up in the equipment, it hasn't been spent efficiently towards achieving the end goal here. Bail out now while the full value is still intact. So many before you have found the equipment you have works well enough at first, until the first transistor blows up.
The next mistake is just replacing the one that went bad. If he does this with his 8 spares, the amplifier will never run balanced again and will be much easier to blow up the next time. Most people won't understand the need to pull all 8 and replace them with new ones that still have high gain and are all very similar in performance if not exact. The other 7 have all been subjected to the same abuse that caused one to fail and have most likely suffered some reduction in gain as a result.
Plus, how long is he going to sit behind a new HF rig with all of those capabilities, before there may be a desire to operate other bands? It's unlikely the Texas Star will behave well on any of the lower bands since it was obviously optimized for 11 meter performance. The only benefit in using what you have now, is because you already have it. Your application strongly suggests another amplifier would be more appropriate and the existing equipment would fit another persons needs better.
The next mistake is just replacing the one that went bad. If he does this with his 8 spares, the amplifier will never run balanced again and will be much easier to blow up the next time. Most people won't understand the need to pull all 8 and replace them with new ones that still have high gain and are all very similar in performance if not exact. The other 7 have all been subjected to the same abuse that caused one to fail and have most likely suffered some reduction in gain as a result.
Plus, how long is he going to sit behind a new HF rig with all of those capabilities, before there may be a desire to operate other bands? It's unlikely the Texas Star will behave well on any of the lower bands since it was obviously optimized for 11 meter performance. The only benefit in using what you have now, is because you already have it. Your application strongly suggests another amplifier would be more appropriate and the existing equipment would fit another persons needs better.
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You know, almost all the peeps I talk to believe that the Toshiba 2SC2879A RoHS compliant "Red dot" Toshibas are a better part than the Toshiba 2SC2879 "non red dot" when they are genuinely mistaken. You covered it pretty well, there Shockwave. Beryllium oxide is a better heat dissipating ceramic over the RoHS Aluminum Nitrate ceramic and because of the better uniformity of crystalline it also has a lower dielectric constant which delivers improved circuit performance. That is your major difference between long term performance and early failure. So opt out for the non red dot Toshibas as it is clearly a more robust transistor.
I always wonder about the red dots...if you don’t plan on abusing the snot out of them, then does it really matter?
I’ve got a 1X4 with all 2879 red dots. I ran It pretty hard; “only” 15V, but driven hard and a high carrier also. Never had an issue with it.
I’ve got a 1X4 with all 2879 red dots. I ran It pretty hard; “only” 15V, but driven hard and a high carrier also. Never had an issue with it.
Thanks so now that being said I have Texas star dx 1600 using 200 amp power supply that I can run atv14 14.5 volts right for base station with stone wall Jackson
If you run the Dx1600 on SSB with more than 14.2 volts DC you will not see a noticeable increase in output power. But you will see a noticeable increase in heat. That also goes for the Dx500 etc. The Amp runs so much better if you do not increase the voltage. It is not a competition amp designed to run on 15 and more. The bias circuit is not particularly well stabilized and performs poorly when subjected to more volts than it was designed for. Sure it says DX1600. But run it at a KW and it will last a long time and sound nice on SSB. You wouldn't run your car flat out all the time either would you?
There is no protection circuitry in that amp at all. Nothing to stop you running it into a brick wall and blowing it up, except you; the operator.
There is no protection circuitry in that amp at all. Nothing to stop you running it into a brick wall and blowing it up, except you; the operator.
Shadetree Mechanic
Delaware Base Station 808
Run it at 12v and it will be the last amp you ever need to buy.......