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jhorak101
05-17-2016, 03:58 PM
Hello I was at a radio shop where I wanted to buy this 100 amp amplifier. He said I could buy it no problem but was told that he would not have time to tune the amp to my radio. For years I have just seen radio operators just hook up the amp and go I am referring to a transistor type low drive amp. I knew with tube type amps you had to do some tuning but I was told that If I decided to buy this two pill varmint amp that i needed to bring in my cobra 2000 radio so he could match it (tune it) to my radio. Is this tech right ?


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222FL
05-17-2016, 04:13 PM
He may need to lower the dead key on AM on your radio to get it to key the correct power. May only need anywhere from .25-2 watts of dead key on AM. Pep should stay around 8-10 watts max. Amp should key up about 20-25 watts of carrier and swing to about 100 watts of that is the actual rated power. You may see less or more depending on how you drive the amp. And the tech may also need to make sure the input/output tune is in line with your radio as to make all the system see a 50ohm or near 50ohm system. And also make sure that the amp is working correctly. Don't let the tech touch anything else but to lower your DK power. May take the cap/ resistor mod to accomplish this or add a separate RF power knob. Don't use the RF gain knob to make an RF power knob out of it. It will end up burning up. Leave that be and have another knob or switch installed. JMHO. Have a switch to lower DK to whatever power is needed to run amp and with switch off. It will be stock 4 watts carrier on AM. Either way will work better than using the RF gain pot. JMHO.

jhorak101
05-17-2016, 04:17 PM
That is kind of along the lines he was talking about he said this amp works best with about a two watt dead key. But he said it is always best to bring the radio and amp in together and put them on the scope and bird meter and match them up.


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222FL
05-17-2016, 08:26 PM
Good advice. Let him pair the amp to the radio. He is correct and isn't BS'ing you. It will be right if he is going to to do it this way as well. By placing them together on the scope. Clean in equals clean out. So as long as the signal going into amp is clean it should come out clean unless the amp has a lot of harmonics. Most of the time this is due to the amp being over driven. Thus again the need to make sure your radio isn't putting too much power into the amp. The scope will help a bunch as well! Hope you get it all sorted. Sounds as if you have a good tech. Stick with what he is telling you and listen closely about the drive levels into the amp. This will help keep the amp alive for a lot longer if use the amp correctly and don't try to get every watt you can out of it. Clean is mean!!