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Texas Star DX500 max input?
- Thread starter bestro
- Start date
You have seen over 700 watts pep out of a Texas Star 500? 500-550 watts peak is all she'll do. 20-25 watts peak is all you want to drive a TS 500 with.
He wants to know the max PEP input from the radio, not max wattage out from the amp. If your saying you get 700 watts from a DX500 of any vintage you need a new watt meter.
I have seen over 700 playing around with 60-70 watts in which didnt surprise me as its just a 667 without the 2SC2290 driver. There were huge discussions on this verey forum that I got into years ago before I attempted to experiment as others have and seen just what they said they seen. Did anything pop or let go?? NOPE!! Would I run any of my DX500 like that everyday? NOPE? I run 20 - 25 watts in max and get 350-400 out on a true peak reding meter and thats good enough for me to be heard on 10 meters and I know its clean there. Most of the time I will run enough drive to get 200 - 250 watts out and am heard fine there.
I also stress the point to everyone about running a fan on the heatsinks on these Amplifiers and or any anplifier that doesnt have a fan no mater how big the amplifier is because heat is ne cause of death in these devices and for the few dollars it costs for a small computer fan which is sufficiant and a small 12 volt powersource that will last damn near our lifetime running on one amplifier to the next its a win win purchase and saftey precaution.
I also stress the point to everyone about running a fan on the heatsinks on these Amplifiers and or any anplifier that doesnt have a fan no mater how big the amplifier is because heat is ne cause of death in these devices and for the few dollars it costs for a small computer fan which is sufficiant and a small 12 volt powersource that will last damn near our lifetime running on one amplifier to the next its a win win purchase and saftey precaution.
At least you can feel good every time to stare at the marvelous numbers your meter is showing you.
20 to 25 watts peak (example bird w/peak kit) should yield approx 500 watts peak out.
That is why they call it a 500.
I do not doubt that a 500 will produce 700 watts (again peak ) if you drive it hard and feed it all the current it needs at about 14 volts.
I will not run mine that way because if you do not have all your ducks in a row it is that much easier to hurt the amp.
They get hot, you have to put a fan on them even at the 500 watt level.
I run mine at about 350/400 out ( as Tony Posted) on SSB on 10/12 meters and it has provided many years of service.
73
Jeff
That is why they call it a 500.
I do not doubt that a 500 will produce 700 watts (again peak ) if you drive it hard and feed it all the current it needs at about 14 volts.
I will not run mine that way because if you do not have all your ducks in a row it is that much easier to hurt the amp.
They get hot, you have to put a fan on them even at the 500 watt level.
I run mine at about 350/400 out ( as Tony Posted) on SSB on 10/12 meters and it has provided many years of service.
73
Jeff
I would agree with that, drive it with 80-100 watts PEP and a steady 15 volts. You could fry and egg talk on the radio and see 700 watts all at the same time. Probably splatter 10 channels in each direction and get into half the tv sets on your block as well. Until the amp went poof.
I put 100 PEP into my 500v and it still runs pretty cool. I do have fans though. Its my understanding that its the average power that will make your amp run hot. I don't think I'm swinging more than 12 to 15 average but doing close to 100 PEP. No issues and seeing about 535 PEP watts out of it.
I ran a RCI 2950 into a Texas Star V Mod +, which in turn drove a Texas Star DX-500 way back in the early to mid 1990's. 70 watts PEP on the V Mod would produce 700 watts PEP on the DX-500 all day long in my stock 1985 Ford F150. Ran it for at least 4 or 5 years like that, until I bit the bullet and got my technician ticket. I've been told that the current production models won't accept the abuse like the ones back then would. Of course, that seems to be true with just about anything we buy these days....
73
David
Welcome! With the Toshiba transistors being ancient history, the HG transistors used now days would be considered fragile comparitivly. With the bias that the Texas Star amps have, 60w peak drive would be about all I would try. And that might be pushing it...
First off, Welcome to the forum
Your setup then was back in the good o'l days when man was made of steel and machine was made of wood
You've heard correct about the Texas star of today. The problem doesn't really come with the design of the amps because they are still the same design or really close to it. The problem comes from the lack of transistors to do what the toshibas or others of the past could do or in your case "could handle". We're thankful someone will still produce a niche product such as the transistors we use today but the days of the good ones are long behind us. Times have changed in about every department of life as we look around and the amplifier world got it too. There are some really nice radios available today though in the cb world with features we could only dream of back then.
The Toshiba transistors were in production for decades. This product lifespan is a lot longer than many semiconductor products. It was normal in the 1980s for a transistor to get discontinued after only a few years. A new improved part would take its place. The result of a long production life is that their 'cookie cutter' became incredibly well developed. Product quality is fundamentally related to production quantity. The more you make of something, the better you get at it. After the first ten years, Toshiba had an incredibly-high quality level built into the 2SC2879. Made that transistor famous for withstanding double the stresses it was rated for. Of course it's not that different from putting twin turbos on your 4-cylinder daily driver. It will take the stresses, but will wear out sooner than if you left it stock. The Kenwood TS-50 ham HF transceiver used a pair of these in its final stage. The radio was rated for 100 Watts PEP. The final transistors should outlive every other part in the radio at that level.
But nothing lasts forever. European product-safety rules in the early 00s banned a list of toxic substances. The 2SC2879 contained both lead and beryllia ceramic. Both of the were banned beyond 2006 or 2007. Word was that Merrit at RF Parts Inc. sweet-talked Toshiba into redesigning the part with non-toxic substitutes. You can tell this at a glance by looking at the very bottom layer of insulation that rests against the mounting foot. If it's white, it's beryllia the toxic banned substance. If it's gray, that's aluminum nitride, the toxin-free substitute. A red dot next to the printed type number also indicates this version. Nothing lasts forever, and the red-dot version was eventually discontinued. Knock-off parts appeared to fill the vacuum after that. The DEI copy was particularly fragile. Counterfeits abounded, most of them had a short KBK rating, as in Keys Between Kabooms. Hua Gao semiconductor is a legit chinese enterprise. Their "HG" parts are not so robust as the Toshiba transistors became, but they provide legitimate performance if you treat them with respect. But any commodity in short supply is subject to counterfeiting. The HG parts are no exception. The one safe source of the legit part I know is ICA manufacturing, aka "Fat Boy". With any luck they'll be around for a while longer.
73
But nothing lasts forever. European product-safety rules in the early 00s banned a list of toxic substances. The 2SC2879 contained both lead and beryllia ceramic. Both of the were banned beyond 2006 or 2007. Word was that Merrit at RF Parts Inc. sweet-talked Toshiba into redesigning the part with non-toxic substitutes. You can tell this at a glance by looking at the very bottom layer of insulation that rests against the mounting foot. If it's white, it's beryllia the toxic banned substance. If it's gray, that's aluminum nitride, the toxin-free substitute. A red dot next to the printed type number also indicates this version. Nothing lasts forever, and the red-dot version was eventually discontinued. Knock-off parts appeared to fill the vacuum after that. The DEI copy was particularly fragile. Counterfeits abounded, most of them had a short KBK rating, as in Keys Between Kabooms. Hua Gao semiconductor is a legit chinese enterprise. Their "HG" parts are not so robust as the Toshiba transistors became, but they provide legitimate performance if you treat them with respect. But any commodity in short supply is subject to counterfeiting. The HG parts are no exception. The one safe source of the legit part I know is ICA manufacturing, aka "Fat Boy". With any luck they'll be around for a while longer.
73