I am DUMB when it comes to these "NEW" technological wonders in radio amps....HOW can I determine what type of amp and how much minimum and maximum dead key from each particular radio to use on the proper amp...I am told to put in no more than 1 1/2 DK on this and then, no put 4 to 5 watts DK for the same radio...yet no one will tell me WHY and WHAT determines the amount and what to look for when buying an amp for a particular radio. IE one radio will dead key from 0 to 20 watts, depending on how I set the RF Variable. Another one I have will DK no less than 15 watts with max 150 watts...I know I won't need an amp on this one much if at all but I want to know the reasoning behind this and in layman's simple terms PLEASE....Thank You all for any good information you can give to me...I am so darned confused by all these people who obviously do not know what they are talking about....
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Proper amp for radio(S)
- Thread starter TD126
- Start date
Alot of that depends on the amplifier. Some amps are HD (high drive) some are not, and most have HD stamped on there because it will sell better. A general rule of thumb is smaller amplifiers like 2 final amps are low drive, a 4 or 6 final (pill) amp would be able to handle more drive (higher dead key).
Next factor, is the amp a mass produce factory amp or a custom built competition style amp? Factory amplifiers like a Texas Star 250/350 and palomar amplifiers are all pretty much low drive amps, 1-2 watt AM dead key input. Custom built heavy duty amplifiers like X-Force, Davemade, and Fatboy can handle higher input levels.
Next you must decide on what class of amplifier you need. If you plan on talking SSB as well as AM you will want a class B or better yet class AB. Many AM only amplifiers are class C. You will have to just read up on amplifier classes to learn more.
MOSFET powered amplifiers are some what new to the illegal cb market. All I know about these is what specs the builder/seller have listed where ever they are sold. The same concept apply's, the 4 final mosfet can handle more drive then the 2 and so on.
Next factor, is the amp a mass produce factory amp or a custom built competition style amp? Factory amplifiers like a Texas Star 250/350 and palomar amplifiers are all pretty much low drive amps, 1-2 watt AM dead key input. Custom built heavy duty amplifiers like X-Force, Davemade, and Fatboy can handle higher input levels.
Next you must decide on what class of amplifier you need. If you plan on talking SSB as well as AM you will want a class B or better yet class AB. Many AM only amplifiers are class C. You will have to just read up on amplifier classes to learn more.
MOSFET powered amplifiers are some what new to the illegal cb market. All I know about these is what specs the builder/seller have listed where ever they are sold. The same concept apply's, the 4 final mosfet can handle more drive then the 2 and so on.
91CDriver
Thank you 91Cdriver! This helps me understand the principle more than all the "Advice" I have heard from operators...I do have one amp that is for 10 meters that I'd like to use...It is a Dave Made 2 pill competition amp. It has extra large and extra capacitors and has 2 huge power supplies. I have been told both ways on it...don't load it over 3 or 4 watts...then the engineer at the factory says it will handle 100 watts DK....That is a custom made amp. I got it on a trade for a 10 meter base RCI that is supposed to have been made for the RCI 2995DX High Drive. So, do I go with what the factory guy says? half way between both of 'em and drive it at 30-40 watts DK or 3-4 watts DK...Sorry I forgot to include this one....It has a bad relay...terminal broke off and I can't solder anymore due to an inherited condition with nervousness...Nearest Tech I trust is over 100 miles away....OK Thanks again!
Thank you 91Cdriver! This helps me understand the principle more than all the "Advice" I have heard from operators...I do have one amp that is for 10 meters that I'd like to use...It is a Dave Made 2 pill competition amp. It has extra large and extra capacitors and has 2 huge power supplies. I have been told both ways on it...don't load it over 3 or 4 watts...then the engineer at the factory says it will handle 100 watts DK....That is a custom made amp. I got it on a trade for a 10 meter base RCI that is supposed to have been made for the RCI 2995DX High Drive. So, do I go with what the factory guy says? half way between both of 'em and drive it at 30-40 watts DK or 3-4 watts DK...Sorry I forgot to include this one....It has a bad relay...terminal broke off and I can't solder anymore due to an inherited condition with nervousness...Nearest Tech I trust is over 100 miles away....OK Thanks again!
There is no "Engineer at the factory" because there is no factory or engineer. All black market 11m cb amps are built in a garage or basement. Davemade has been around for a long time. A handful of guys build them by hand for AM use and many of there owners tend to overdrive the piss out of their amplifiers. If you read the sprc sheet on 2879's they need under 15 watts drive to reach max output. Even if it was a custom build to handle more all they are doing is adding a bunch of padding in there to eat up the extra drive wattage. All that does is generate heat.
A 2 pill amplifier is in no way shape or form the proper amp for a 2995DX, way way too much radio for that amp. Back to what I said earlier about who builds the amp. A Texas Star 350 (two 2879 finals) likes a 1-2 watt dead key and will function fine at 12-30 watts peak drive. Your Davemade 2 pill (also 2879's) can handle more drive but only a crack smoker would dead key 30+ watts into one.
If you have a radio that can dead key say 3-6 watts and swing 40-50 peak give that a try. When run like that your Davemade will dead key say 90-120 watts and swing 350-400 watts.
A radio like a 2995DX will need an amplifier like this.
TNT 600hd
Or you could run it with an X-Force base amp class B biased like this.
40012 Base
In the end your 2 pill Davemade will not work with a 2995DX.
A 2 pill amplifier is in no way shape or form the proper amp for a 2995DX, way way too much radio for that amp. Back to what I said earlier about who builds the amp. A Texas Star 350 (two 2879 finals) likes a 1-2 watt dead key and will function fine at 12-30 watts peak drive. Your Davemade 2 pill (also 2879's) can handle more drive but only a crack smoker would dead key 30+ watts into one.
If you have a radio that can dead key say 3-6 watts and swing 40-50 peak give that a try. When run like that your Davemade will dead key say 90-120 watts and swing 350-400 watts.
A radio like a 2995DX will need an amplifier like this.
TNT 600hd
Or you could run it with an X-Force base amp class B biased like this.
40012 Base
In the end your 2 pill Davemade will not work with a 2995DX.
The recommended drive for a true competition 2x2879 amp is 100-120 watts peak and that'll get you 400 watts peak watts output.
I would run a 2 pill amp at 100-125 watts key and 4-6 watts input key usually does it.
Before the "Purists" nail me to the cross, I know people who have run them like this for 12 years with no failures.
I would run a 2 pill amp at 100-125 watts key and 4-6 watts input key usually does it.
Before the "Purists" nail me to the cross, I know people who have run them like this for 12 years with no failures.
yep,alot of garage garbage,and basement bargin crap.Go with a good amp,and run right will last a long time unless a failure in coax,or antennas.davemade,Wizard,or xforce have been around for many years...
I don't even know if there is such a thing as hi drive or lo drive amplifiers. There are a lot of deciding factors for drive requirements like device gain and class of operation etc. But if I had to categorize them, I'd call anything with a driver section a lo drive .... 1x* or 2x* and anything without a driver section a hi drive.
There was another guy on another forum asking the same question though and wanted a hard fast rule for setting carrier levels with different amps and radios. My answer made him mad, but I'm going to give the same answer here.
Reference the device data sheet, amp builders can make any claim they want, but the bottom line is the data sheet. Then start with a low carrier making sure you have headroom to fully modulate your audio. If you are swinging an average meter backwards, or can't reach 4x the carrier on a peak reading meter, you don't have the headroom you need and the carrier is too high.
So instead of saying 1.5w across the board or whatever numbers guys like to throw around, this way you know where you need to be for any combination of amps or radios.
That's my thought on the subject anyway.
There was another guy on another forum asking the same question though and wanted a hard fast rule for setting carrier levels with different amps and radios. My answer made him mad, but I'm going to give the same answer here.
Reference the device data sheet, amp builders can make any claim they want, but the bottom line is the data sheet. Then start with a low carrier making sure you have headroom to fully modulate your audio. If you are swinging an average meter backwards, or can't reach 4x the carrier on a peak reading meter, you don't have the headroom you need and the carrier is too high.
So instead of saying 1.5w across the board or whatever numbers guys like to throw around, this way you know where you need to be for any combination of amps or radios.
That's my thought on the subject anyway.
I'm pretty sure you know the answer here, but they are designed for shootouts only. They are biased deep in class C, made to take upwards of 20v and take lots of drive.
Just my 2 cents on the subject.
Every amp will require different power to key up.
What drive power is needed for an amp? If I have variable power on the radio I start with the power is at the lowest possible and key up on AM, listening for the amp to key. I gradually increase power by repeating keying and listening for the amp to key up until the amp keys, then I keep it at that power level on the radio. I find it's simple and for the most part does not over drive the amp.
Every amp will require different power to key up.
What drive power is needed for an amp? If I have variable power on the radio I start with the power is at the lowest possible and key up on AM, listening for the amp to key. I gradually increase power by repeating keying and listening for the amp to key up until the amp keys, then I keep it at that power level on the radio. I find it's simple and for the most part does not over drive the amp.
You do that quite often, but I'm pretty sure you haven't swayed and of the people who buy them. So I guess we both just wasted some bandwidth
- No one is chatting at the moment.