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Need some expertize opinion

Run the 500v with the green button out (not lit up), this will bypass the variable pot completely and the amp will run wide open. Then you can somewhat control the output with the variable on the radio.

On AM once you have a 70-90 watt dead key out from the amp see what your peak power is, probably be 350-400. You should be good to go. If your amp has Toshiba finals then 100-125 swinging 450-500 could happen easy with a 955 driving it.

On SSB once your radio is doing 25-30 watts it should drive a 500v quite well and you should not need to hit it any harder. Last 500v I had would hit 450+ watts on SSB with only 18-20 watts PEP input. You will have to just mess with it and see how a new one responds.

As always, thank you . Toshiba finals, nope . Just shitty DEI.

Your logic in respect of power is spot on to what I have come to learn, thanks.

So moral of the story, dont turn the variable on the 955 up.?
 
I don't like to talk about "swing" (because that is a some-what subjective term)
BUT regarding A.M., if the radio is bone stock, and will not "swing" to a 100% modulation output ratio from the dead carrier, the adjustment variable resistor (potentiometer) will need a slight tweak...

A slight bump of the AMC pot, will help you see that 4:1 p.e.p.:carrier ratio if the radio can't do it already. (It should be able to do 100% or close from the factory, I'd hope.)
&
I would run the variable output of the radio turned down completely, the amplifier should not produce a huge carrier then, if it is too large w/ the variable all the way down.. the internal pot(s) will need to be tweaked, I'd adjust the internal AM carrier (Hi/Lo) pots to change the range of the variable knob on the front of the radio.
(make it so the radio has a lower carrier, to better accommodate the amplifier)

The goal being not to stress the transistors, and improve the service life of them; so less carrier output = less stress on the parts (in a very basic way), too much input into the amp (or carrier/ "dead key" from the radio) for too long, can equal too much heat, and then pop!
I am surprised you turned the variable all the way up on the Stryker, and saw that much CW power..


"They say, let the audio do the work" meaning, you will see the bigger output numbers when you modulate. The whole idea of swing is that a lowered carrier (out of the radio) going into the amplifier, equals a low carrier out of the amplifier (less than half of the max CW power it can create, closer to 1/4 of its max.. this leaves gobs of head-room for modulation) then the radio modulates the carrier, but, because you have so much head room, the audio peaks are amplified "better" and "somehow" this affects the audio, imagine instead you made the amplifier produce a 200 watt carrier,
this creates more heat/stress in the parts and leaves much less headroom for the audio-peaks.
(this would sound muddy/over-driven as opposed to clean and clear with the lower carrier)

That low carrier, and high peak output will show up on the peak reading watt meter (placed after the amplifier) because it will look like a Vu meter swinging about while you are talking, lol; good fun!

You could set it up to "super-modulate" and exceed the 4:1 ratio, that would be like a 50 watt carrier "swinging" to 400-500 Watts p.e.p. out instead of 200 watts p.e.p., only issue is that it takes knowledge and experience to go beyond 100% modulation cleanly and steadily (not just the odd voice peak doing it) without the right setup, super-modulation will lead to in-band splatter, like cross-channel bleed over.

Some Magnum radios are set to produce forced-asymmetry, creating huge "swing" from any carrier setting, that leads to massive modulation percentages, and in theory, what I call a LOUD signal.. But debate exists regarding that topic, it's best suited for another thread, I only mention "super-modulation" because, undoubtedly, if you run A.M. mode, you are bound to receive some "iffy" suggestions from other operators if you ask/discuss amp setup on air.. (been my experience anyway)

This is all regarding Ancient Modulation ;) not single side band, and I apologize for my wall of text + pseudo-scientific gibber-jabber. (y)
 
Last edited:
I don't like to talk about "swing" (because that is a some-what subjective term)
BUT regarding A.M., if the radio is bone stock, and will not "swing" to a 100% modulation output ratio from the dead carrier, the adjustment variable resistor (potentiometer) will need a slight tweak...

A slight bump of the AMC pot, will help you see that 4:1 p.e.p.:carrier ratio if the radio can't do it already. (It should be able to do 100% or close from the factory, I'd hope.)
&
I would run the variable output of the radio turned down completely, the amplifier should not produce a huge carrier then, if it is too large w/ the variable all the way down.. the internal pot(s) will need to be tweaked, I'd adjust the internal AM carrier (Hi/Lo) pots to change the range of the variable knob on the front of the radio.
(make it so the radio has a lower carrier, to better accommodate the amplifier)

The goal being not to stress the transistors, and improve the service life of them; so less carrier output = less stress on the parts (in a very basic way), too much input into the amp (or carrier/ "dead key" from the radio) for too long, can equal too much heat, and then pop!
I am surprised you turned the variable all the way up on the Stryker, and saw that much CW power..


"They say, let the audio do the work" meaning, you will see the bigger output numbers when you modulate. The whole idea of swing is that a lowered carrier (out of the radio) going into the amplifier, equals a low carrier out of the amplifier (less than half of the max CW power it can create, closer to 1/4 of its max.. this leaves gobs of head-room for modulation) then the radio modulates the carrier, but, because you have so much head room, the audio peaks are amplified "better" and "somehow" this affects the audio, imagine instead you made the amplifier produce a 200 watt carrier,
this creates more heat/stress in the parts and leaves much less headroom for the audio-peaks.
(this would sound muddy/over-driven as opposed to clean and clear with the lower carrier)

That low carrier, and high peak output will show up on the peak reading watt meter (placed after the amplifier) because it will look like a Vu meter swinging about while you are talking, lol; good fun!

You could set it up to "super-modulate" and exceed the 4:1 ratio, that would be like a 50 watt carrier "swinging" to 400-500 Watts p.e.p. out instead of 200 watts p.e.p., only issue is that it takes knowledge and experience to go beyond 100% modulation cleanly and steadily (not just the odd voice peak doing it) without the right setup, super-modulation will lead to in-band splatter like cross-channel bleed over.

Some Magnum radios are set to produce forced-asymmetry, creating huge "swing" from any carrier setting, that leads to massive modulation percentages, and in theory, what I call a LOUD signal.. But debate exists regarding that topic, it's best suited for another thread, I only mention "super-modulation" because, undoubtedly, if you run A.M. mode, you are bound to receive some "iffy" suggestions from other operators if you ask/discuss amp setup on air.. (been my experience anyway)

Anyway that is all regarding Ancient Modulation ;) not single side band, and I apologize for my wall of text and pseudo-scientific gibber-jabber.

Thanks for the reply, I think this time I will allow a tech with apparatus to adjust my 955 pots to work optimally with the dx500v amp.

Just for the record, i didnt run any modulation when I increased the deadkey on the radio until the amp was dking 400w. It was a mere clockwise turn on the RF power on radio fully then back to bare min again. Was just checking that all 4 DEI transitors were working or not.

Fourstringburn taught me a while ago about the 1:4 ratio, and how bad high deadkey could be in given setups. Figured it was a quick

Currently 5W deadkey on radio translates to 100W deadkey on amp , modulates to about 300w on amp.
4W is the lowest the RF knob on radio goes to at a deadkey of 80W on amp. This modulates the amp to 250w pep.
Like I mentioned earlier the radio by itself doesn't swing 1:4 hence why I'm seeing these figures translated on amp ;-)

Thanks
 
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