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

[Captain Kilowatt]

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.

You are accomplishing tbe same tbing either way however using audio gain can be tricky. A change in voice level or a different voice could very well overdrive tbe amp. Using the RF power control limits max output regardless of audio levels. I have NEVER used a mic gain to control power out on SSB in over 35 years of playing radio. It can be done but I choose not too.

 

[222DBFL]

I thought it was Wierd as well, but for my radio it's what the addendum that was taped on top stated to do. I use a meter at all times and always check my levels, maybe I have been lucky but I ran my amp in ssb mode and turned power to full rf power and never had any issues with it, always got good reports with it. I don't have it in line anymore so I can't test any further or I would.

 

[9C1Driver]

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.

You asked for help and now you don't like the answers. You seem to be dodging the question, WHAT 4 PILL AMP DO YOU HAVE ???????

By the way, most 95T radio's will swing over 100 watts even with a 5 watt carrier. Depending on the amp 100+ peak watts will overdrive it.

 

[roadrage]

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.

The problem with that is when the radio is at full power on SSB, the amp output peaks are about way too high. Even at half throttle I am seeing 750W. That is way to much output for those transistors to run cleanly or safely. Anything over 500W is too much. I am trying to keep things clean. I am thinking that possibly there is something wrong with the keying circuit? If I turn the power up a little, the problem goes away but has too much final output. So I'm probably bleeding all over and sounding bad. Or I can lower my drive and have the amp cutting out. On AM everything is working well and sounding very clean. My only problem is SSB. I was hoping that it might be an easy fix, but I think it needs a look from someone who knows more than I do. 110W barefoot is still respectable and gets it done. I listen more than I talk anyway.

 

[roadrage]

You asked for help and now you don't like the answers. You seem to be dodging the question, WHAT 4 PILL AMP DO YOU HAVE ???????

By the way, most 95T radio's will swing over 100 watts even with a 5 watt carrier. Depending on the amp 100+ peak watts will overdrive it.

Not dodging. It is a TNT 600HD 4X2879 class B. They do build them with a lot of padding for high swinging radios. My radio still swings up a bit at low power, but not as much as full. I am seeing about 60W peak on AM and 5W dead key. That gives me a pretty good 1:4 ratio out of the amp and still fall within spec of the transistors.

My SSB problem is something that just started happening so I am thinking that there has been a component failure of some sort.

 

[9C1Driver]

Not dodging. It is a TNT 600HD 4X2879 class B. They do build them with a lot of padding for high swinging radios. My radio still swings up a bit at low power, but not as much as full. I am seeing about 60W peak on AM and 5W dead key. That gives me a pretty good 1:4 ratio out of the amp and still fall within spec of the transistors.

My SSB problem is something that just started happening so I am thinking that there has been a component failure of some sort.

I would agree, the TnT 600 is a beast. A local used to run one with an Omegaforce HP and sounded superb. Did about 700 ish watts on SSB with the Omega doing 70 watts.

 

[Captain Kilowatt]

I thought it was Wierd as well, but for my radio it's what the addendum that was taped on top stated to do. I use a meter at all times and always check my levels, maybe I have been lucky but I ran my amp in ssb mode and turned power to full rf power and never had any issues with it, always got good reports with it. I don't have it in line anymore so I can't test any further or I would.

What radio was it? I can remember only one or two older HF radios that had no RF power output control that recommended the power out on SSB be controlled with the microphone gain control.

 

[Captain Kilowatt]

Not dodging. It is a TNT 600HD 4X2879 class B. They do build them with a lot of padding for high swinging radios. My radio still swings up a bit at low power, but not as much as full. I am seeing about 60W peak on AM and 5W dead key. That gives me a pretty good 1:4 ratio out of the amp and still fall within spec of the transistors.

My SSB problem is something that just started happening so I am thinking that there has been a component failure of some sort.

OK well that clears up a few things. Didn't know it was working fine before and then just started to act up.Has the input SWR into the amp with it on changed any? Wondering if the input padding has been cooked. Perhaps check to see if the transistor bias voltage is still present to make sure it is still class B and not operating class C.

 

[222DBFL]

It's a magnum 257hp, it's a newer radio, it had a note attached stating that when using ssb, turn rf power to max and use mic gain for control of power (modulation).

 

[roadrage]

OK well that clears up a few things. Didn't know it was working fine before and then just started to act up.Has the input SWR into the amp with it on changed any? Wondering if the input padding has been cooked. Perhaps check to see if the transistor bias voltage is still present to make sure it is still class B and not operating class C.

Thank you. I will see.

 

[roadrage]

Still haven't had time to open up the amp. Strangely, the problem has gone away. I was checking out a different mic and flipped over to SSB and things were working. I put the original mic back on and it is still working (but who knows for how long).

Radio at full power, mic gain at 1/4 and amp on, it just worked last night. Being that it was working, I asked for a radio check on 38 lsb. I was told "you are sounding beautifully over hear. What are you running?" I am seeing a more proper output 450W-500W instead of 700W I was seeing before. And it isn't cutting out. Maybe I have a bad connection. The Golden Road is getting pretty rough these days.

I also noticed that I have a subtle high pitched whine coming from the amp on AM now. SWR is still 1.3:1. I am thinking I should send it out for look.

 

[Captain Kilowatt]

Oh jeeesh I hate intermittents. I have fought enough of them in my lifetime. :headbang