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Talking about amps ... who are the better ab1 manufactures?

Robb said:
So long as you limit the input power to 12-14 clean/peak watts with an accurate peak-reading meter (not a Dosy) - IIRC. It does have an AB bias circuit installed . . .
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Exactly. Any amplifier short of the class "C" splatter cannons (not designed for ssb use) that is run way over their spec ratings will run dirty. Dosent anyone remember the 4:1 ratio? This is another one of those questions that if you ask 100 people you will get 150 different answers.

If the amplifier is baised correctly and it is run within the device specs it should perform ok, and last for years. The texas Star Amplifiers are going to be your best bet in a commercially built unit. Can a better amplifier be had....Sure, if you take the time and effort to built it yourself and focus on half decient output filtering. But in that arena it seems like large class "c" amps are what the masses are interested in with no real interest in adding bias or output filtering at all.

M42duster: Yes there is some IMD produced with the Texas Star amplifiers, but FAR LESS than a class "c" unit. They care to an extent, but not anywhere near what a ham op would.

Here is something to keep in mind,

I have been working with the T.S. units for years and here is something that those who run these amps would like to know. There is a common fault with these amplifiers in the bias devider network. After the amplifier has some years on it the sandbar resistors slip out of tolerence. Since they spend 99% of their time in a heated condition the 25 ohm rating can go as high as 40 ohms thus reducing the bias voltage, and the bias current. These are wear items and should be checked out at least once every two years in my opinion.

The other thing that you might want to know is that there ws a design change with the two 10uf chokes. they are being made with a thicker winding on the choke form and seem to reduce the harmonic infiltration onto the transistors a little better than the older design. As they too go high in resistance further lowering the voltage/current.


Wire Dawg: some excellent advice there. I too have used these for years with mininal issues. But we also need to remember that having a properly tuned radio is also the key for clean operation. I have seen so many rigs way out of tune causing IMD, and harmonic issues that any amplifier will make worse. The old adage "garbage in = garbage out" Is only valid half the time as an out of tune radio makes up the other half.

If you aren't planning on building an amplifier yourself, Then I would have to agree that the Texas Star is your best bet.

If you want to run as clean as possible and still want to be herd, operate a stock properly tuned rig and go with a larger amplifier than you think you will need and run it at minimum. This way you give yourself a little head room and still operate a clean station. All of the support items go without saying ie. propper grounding, swr and the like.

Good luck.
 
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Thanks all ...Great info. I am looking at a Messenger Amp. Not new but from what I have read ... not a bad amp for said applications.

Again ...
Thanks for all the replies.
 
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bighammer said:
Do you believe that a texas star is really a clean ab1 because they list it as one?
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Those that believe every advertisement and marketing gimmick are the primary victims of consumerism in our capitalistic model. Look at your own purchases, and reflect as to whether such items have delivered everything listed in their advertisements. So, the answer to your question is no. My opinion is that “clean” is a relative term. Most Texas Star (TS) amps do deliver a very clean sounding signal. Some purists, and many with an inferiority complex that insist in putting the CB radio enthusiast crowd into their own category of ‘ignorant hillbillies using class C lynears’, will argue otherwise. TS amps are claimed to be AB biased, and when compared with the other out-of-the-box brands, these remain among the best choices that a consumer can make for a radio station (regardless if they meet some know-it-alls standard).
 
TS does indeed have a bias circuit installed that allows AB biasing. XForce, DaveMade, FatBoy and others do not; they will put it in at an additional cost. Pretty sure that XForce is the exception as none of their amps have AB biasing or will even give you the option.

One can make some amps that are C biased into a AB bias by altering them:

http://www.worldwidedx.com/amplifiers/93982-quick-dirty-class-ab-mod-kl300p.html

http://www.nr6ca.org/ab-bias.html

http://www.sm0vpo.com/tx/rf_pa_cct_00.htm

Running the proper amount of wattage into the input is essential in keeping it stay AB biased. If your radio interest is limited to AM only, then running an AB biased amp is still in your best interest. If you should get interested in SSB; then your AB biased amp will be ready to use.
 
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Robb said:
TS does indeed have a bias circuit installed that allows AB biasing. XForce, DaveMade, FatBoy and others do not; they will put it in at an additional cost. Pretty sure that XForce is the exception as none of their amps have AB biasing or will even give you the option.

One can make some amps that are C biased into a AB bias by altering them:

http://www.worldwidedx.com/amplifiers/93982-quick-dirty-class-ab-mod-kl300p.html

Converting class C amplifiers to linear operation

BASIC LINEAR AMPLIFIERS by SM0VPO

Running the proper amount of wattage into the input is essential in keeping it stay AB biased. If your radio interest is limited to AM only, then running an AB biased amp is still in your best interest. If you should get interested in SSB; then your AB biased amp will be ready to use.
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Thanks ...
 
It seems that that the "clean signals from class "c" pretty much explains it in it's entirety.

The whole point in operating a radio is to keep the majority your signal on the desired operating frequency. I seen the video that homer posted. Even though it has been said that it sounded "clean", It is only a suggestive opinon. Now what should have been done in addition to that was have a recording 0f what was being heard on 55.14, 82.71Mhz. As you may be supprised as to what you hear.

I think most would find it more challenging to build an amplifier and keep the IMD and harmonics down below the suggested ratings to keep from interfearing with others.

But this part of the hobby's morality is slipping away especailly when there is big $$$ to be made off these class "c" amplifiers. Why anyone would trade off being as clean as they can over efficiency is beyond me. Being the Biggest in the playground isn't always where it's at.


But as it was stated in the before mentioned threads you cannot escape the facts.
 
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In technical terms... Good stuff

The Mad Scientist said:
It seems that that the "clean signals from class "c" pretty much explains it in it's entirety.

The whole point in operating a radio is to keep the majority your signal on the desired operating frequency. I seen the video that homer posted. Even though it has been said that it sounded "clean", It is only a suggestive opinon. Now what should have been done in addition to that was have a recording 0f what was being heard on 55.14, 82.71Mhz. As you may be supprised as to what you hear.

I think most would find it more challenging to build an amplifier and keep the IMD and harmonics down below the suggested ratings to keep from interfearing with others.

But this part of the hobby's morality is slipping away especailly when there is big $$$ to be made off these class "c" amplifiers. Why anyone would trade off being as clean as they can over efficiency is beyond me. Being the Biggest in the playground isn't always where it's at.


But as it was stated in the before mentioned threads you cannot escape the facts.
Click to expand...
 
While I have to agree with the TS amps, XForce claims that their Mosfet line are B class. I had a cover off of one when I had 1 and there was biasing in it.
 
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i have been using a tnt 350hd for about 4 years now on 10 meters and I never even mention what i am talking on and everyone says it sounds good. of course i don't over drive it.. i just take what mother nature gives.
 
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gamegetter said:
i have been using a tnt 350hd for about 4 years now on 10 meters and I never even mention what i am talking on and everyone says it sounds good. of course i don't over drive it.. i just take what mother nature gives.
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I was thinking... (can be dangerous to my health).
What would the outcome be if you added a 10 metre filter like this FL1-10 - Harmonic Filters into the tnt350hd.
 
linear amp

The best bet is to buy an hla 150
made by rm italy . it has the proper
filters built in . and its clean @ 90 watts
pep. 25 watt carrier. forget about swinging
watt meters. focus on spectural purity and
the power being kept on the fundamedal frequency
and everyone will be happy. w8ji has a test on the
rm hla 150 which is good info. google it and enjoy.
 
Texas Star DX 350 HDV

I have a Texas Star amp Dx 350 HDV with 2 X 2879's running with a RCI 2950 DX on ten meters SSB and if you are not clean on ten they will tell you. Nice amps but I would add a fan to keep it cool and don't max it out for every last watt.Several people I know swear by the 4 X 2879's in the DX 500 HDV and run them with ham radios with good reports on 10 and 11 meters and would run nothing else. :wink:
 

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