Just when I think all is well...SSB amp prob

[roadrage]

SSB problems with amplifier. On AM things are great. Audio is on channel and clean. I am running the amp to the transistor spec, not the amplifier's manufacture's spec.

If I shut off the amp and flip the radio mode selector to LSB. At full power and mic gain at 1/4 my Galaxy 95t2 shows 110W on my wattmeter. I'm not getting rave audio reports but not bad ones either. It is an export so I'm not expecting miracles from it. Now I turn the power down on the radio and flip on the amp and the amp's SSB delay. I key up and my power output on the radio's meter and external meter show output that keeps cutting out. I turned off the SSB delay and got chatter when not speaking (which I know is normal) but when I speak things seem to work closer to normal. I turn the SSB delay back on and the problem returns. I tried to lower my V-power and increase it as well and there is no change. I tried playing with the mic gain and no change. The radio seems to have normal output with the amp off. Any ideas?

 

[n0zna]

try a different patch cord

 

[222DBFL]

I know that on my magnum 257hp, you turn the rf power all the way up and use the mic gain for modulation, as there is no carrier for ssb. Maybe try turning the power up. I have run my magna force 350hd like this on ssb , rf power all the way up. Zero watts when I key up and full modulation when speaking. Amp never gets warm and I always got good reports. Good luck and hope you get it sorted out.

 

[roadrage]

I know that on my magnum 257hp, you turn the rf power all the way up and use the mic gain for modulation, as there is no carrier for ssb. Maybe try turning the power up. I have run my magna force 350hd like this on ssb , rf power all the way up. Zero watts when I key up and full modulation when speaking. Amp never gets warm and I always got good reports. Good luck and hope you get it sorted out.

I appreciate the reply. I know that SSB has no carrier signal, which is what causes the chatter in the amp when I turn off the SSB delay. I can't run my RF power all the way up with a 150W radio into a 4 transistor amp. I know I am going to get someone tell me not to run a dual final into my amp, but the amp was made to run with a 2 transistor amp to drive it. My radio has a 2x 2290 section built in. The power has to be very low on the radio. On AM I put 5W carrier into the amp. When I adjusted the RF power, it was to adjust the peak output. I wasn't sure if the output on SSB was too much drive for the amp or not enough. Just a process of troubleshooting and information gathering before I start asking questions.


n0nza, I am not a tech. I'm not sure what a patch cord is, could you try to explain what I'd be looking for/at?

 

[Captain Kilowatt]

A patch cord is the short piece of coax cable between the radio and the amp. I doubt that is the issue as it works on AM. I think you are driving the amp way too hard. How many watts are you driving it with on SSB? Try reducing it ands see what happens.

 

[magnuman]

Sounds like he is overloading the power supply

 

[psycho]

Someone doesn't know how to run their amp properly.
Using a radio with 2 x 2290 to drive a 4 pill with the hope of good SSB operation has unrealistic expectations.

 

[Captain Kilowatt]

What amp is it? Maybe it is a class C crapbox and will not work very well on SSB. Just because it has an SSB switch does not mean it is meant for SSB. All that switch does is switch a capacitor in to hold the relay between voice peaks.

 

[loosecannon]

what is the point of running a 4 pill amp after a 2 pill radio???

you have basically made a 2 driving 4 amplifier, which is a crappy design from the get go.

it is a great way to make your wattmeter lie to you though!

the 2 pill driver section drives the 4 pill section right into saturation and they start spewing harmonics which make wattmeters show more watts, but doesnt help your signal one bit.

if a 2 pill amp does 150 watts PEP, then the equivalent 4 pill will do around 300 watts. about a 1/2 an S unit increase.

if your 4 pill seems like it will do a lot more watts than double the 2 pill output, then the transistors are being driven into saturation and your wattmeter is lying to you.

it sounds to me like you are overdriving the input of the amp in order to see numbers on the wattmeter that allow you to believe that its worth it to have it in line, but that is not the truth.

the truth is, if you just run the radio with the power up at a normal level, then you are doing just about as well as with the amp in line.
probably putting out a much cleaner signal also.
LC

 

[9C1Driver]

what is the point of running a 4 pill amp after a 2 pill radio???

you have basically made a 2 driving 4 amplifier, which is a crappy design from the get go.

it is a great way to make your wattmeter lie to you though!

the 2 pill driver section drives the 4 pill section right into saturation and they start spewing harmonics which make wattmeters show more watts, but doesnt help your signal one bit.

if a 2 pill amp does 150 watts PEP, then the equivalent 4 pill will do around 300 watts. about a 1/2 an S unit increase.

if your 4 pill seems like it will do a lot more watts than double the 2 pill output, then the transistors are being driven into saturation and your wattmeter is lying to you.

it sounds to me like you are overdriving the input of the amp in order to see numbers on the wattmeter that allow you to believe that its worth it to have it in line, but that is not the truth.

the truth is, if you just run the radio with the power up at a normal level, then you are doing just about as well as with the amp in line.
probably putting out a much cleaner signal also.
LC

Very well put, some people continue to try and drive that square peg into a round hole.

 

[roadrage]

A patch cord is the short piece of coax cable between the radio and the amp. I doubt that is the issue as it works on AM. I think you are driving the amp way too hard. How many watts are you driving it with on SSB? Try reducing it ands see what happens.

I have it turned down all the way. I think I have to just run the radio barefoot on SSB.

 

[roadrage]

what is the point of running a 4 pill amp after a 2 pill radio???

you have basically made a 2 driving 4 amplifier, which is a crappy design from the get go.

it is a great way to make your wattmeter lie to you though!

the 2 pill driver section drives the 4 pill section right into saturation and they start spewing harmonics which make wattmeters show more watts, but doesnt help your signal one bit.

if a 2 pill amp does 150 watts PEP, then the equivalent 4 pill will do around 300 watts. about a 1/2 an S unit increase.

if your 4 pill seems like it will do a lot more watts than double the 2 pill output, then the transistors are being driven into saturation and your wattmeter is lying to you.

it sounds to me like you are overdriving the input of the amp in order to see numbers on the wattmeter that allow you to believe that its worth it to have it in line, but that is not the truth.

the truth is, if you just run the radio with the power up at a normal level, then you are doing just about as well as with the amp in line.
probably putting out a much cleaner signal also.
LC

Don't pretend to know what I am trying to do. Seriously, the arrogance some people have is astounding. Some of you need to step down from your soap boxes. There is a variable power for a reason. No one said I was using full power of the two 2290s. On AM I have my power into my amp at 5 whole freakin watts. WOW!!!!! That's really some serious overdrive there. Keep your assumptions to yourself. If you have nothing constructive to say, just remain silent. Sometimes it is like dealing with small children on here.

Yes, we all know that it takes 4 times the power for 1 S-unit increase. In real world that means nothing. I've had readable transmissions that hardly move my needle. I don't care what the S meter shows. So contrary to that little rule of thumb, the difference between putting out a 40W carrier on AM or a 150W carrier or having 110W PEP vs 500W pep on SSB can mean the difference between making a contact and being lost in the crowd. Yes, it makes a difference.

 

[roadrage]

What amp is it? Maybe it is a class C crapbox and will not work very well on SSB. Just because it has an SSB switch does not mean it is meant for SSB. All that switch does is switch a capacitor in to hold the relay between voice peaks.

I am really sighing with some of the replies here. No, it isn't a class C crap box. The problem acutally goes away if I turn up the power. The problem is that when I turn up the power to a point that the amp transmits, it is way over driven. I don't want to be over driven. SO as I said, I"ll have to run barefoot on SSB.

 

[Captain Kilowatt]

WHAT KIND OF AMP IS IT? What you describe is classic of a class C amp to a point. Class C requires more drive to switch the transistors into conduction. Help us help you. Give us the type of amp and what the drive level you are using on SSB. You have 5 watts drive on AM but what about on SSB? Just necause the variable output is set the same does not mean the pwr on SSB is the same as on AM.

 

[222DBFL]

You should be able to run the rf power at full gain on ssb and still not produce any watts until you modulate correct. If this is the case then how can you hurt your amp by running the rf power at max on ssb as there is no carrier or dead key watts on ssb correct?? I am asking here as well. Like I posted earlier I know with my radio that on ssb you turn the rf power to max and use the mic gain to control the amount of modulation. I use a magnum 257hp and run a magna force 350hd amp. I run my rf power at max on ssb and use the mic gain with my watt meter as reference to the carrier. Turning the mic gain down keeps the carrier level at or near zero watts until I talk (modulate). I could be way off base here and totally wrong, just posting my experience. Good luck and hope you get it resolved.