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High drive amps
- Thread starter 743SEPA
- Start date
The answer to that question is going to vary depending on the configuration of your amplifier without knowing what amp you're actually using and how it's configured nobody can reliably answer that question..... honestly the best thing to do is hook a watt meter and a dummy load up to the thing and test it out with your radio and the output levels vs configuration of the amp....
Keep in mind also just because an amplifier has HD stamped on it does not mean it really is. When they are built they know an amp will sell better that way. It comes down to how many finals are in the amplifier, what finals they are, and how the amp was built.
So an amp with 4,6,or 8 finals would be more of a high drive amp then a 2 final amplifier. As far as finals the 2879 is a much bigger final then say a 2290, 454, or 455. Last would be some of the custom built amplifiers like X-Force, Davemade, and Fatboy by the nature of their construction in some cases can and do handle much more drive.
For the most part people tend to overdrive their amplifiers. As an example I have found with my Texas Star 250 and 350HDV amplifiers on SSB I can get full output with 8-12 watts PEP.
So an amp with 4,6,or 8 finals would be more of a high drive amp then a 2 final amplifier. As far as finals the 2879 is a much bigger final then say a 2290, 454, or 455. Last would be some of the custom built amplifiers like X-Force, Davemade, and Fatboy by the nature of their construction in some cases can and do handle much more drive.
For the most part people tend to overdrive their amplifiers. As an example I have found with my Texas Star 250 and 350HDV amplifiers on SSB I can get full output with 8-12 watts PEP.
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A customer will occasionally ask "What's that mean, High Drive?" on the front of his amplifier.
I reply that there are two possible interpretations:
1) "We knew you wanted to see this so here it is"
2) "Please blow it up soon and come back to buy another one"
73
I reply that there are two possible interpretations:
1) "We knew you wanted to see this so here it is"
2) "Please blow it up soon and come back to buy another one"
73
Shadetree Mechanic
Delaware Base Station 808
I have a 350HD and it is a great little amp. As with any amp, one of the first things you should check is the SWR between the radio and the amp. I hear that a lot of the Texas Star amps have this problem I suspect because they are designed for 10m operation. My SWR was about 5:1 and I was able to coil up some coax to help it but I wanted a better solution. With the help and knowledge of the people on this great forum, this is what I did:
https://www.worldwidedx.com/threads/texas-star-dx-350-hdv-input-swr.230089/#post-627003
https://www.worldwidedx.com/threads/texas-star-dx-350-hdv-input-swr.230089/#post-627003
Shadetree Mechanic
Delaware Base Station 808
Checking the input SWR is the only thing I know to look for. I suspect that they are tuned for 10m but I would still check.
Shadetree Mechanic
Delaware Base Station 808
Yes before the amp just to check the amps input tuning. Checking the SWR at the amps output to the antenna is important too. The input of the amp needs to look like a 50 ohm antenna to the radio at the frequency it is transmitting on or at least close enough to keep the finals in the radio safe.
With the outrageous price to replace old sweep tubes I can't imagine why people still buy these amps, have them upgraded and re-tubed. I can see someone spending upwards of 400-500 dollars to re-tube and update a sweep tube amp with many tubes in it. There are amps out there which have much better suited tubes for RF use than using TV sweep tubes. Hey, they were great when radio shack sold life time guaranteed sweep tubes. Now it is a different story. If it takes more than 2 tubes to give you the power you want then you are using the wrong tube. These days the minimum tube for RF use should be a 572b. I would skip right over an 811. Then after that a 3-500. Sure these will be high drive amps and not well suited for 5-10 watts of drive. To solve that problem there are now many many ham rigs in the 100 watt class which can be used. 300-400 would buy you one or maybe even less.