Dx500 vs DX1600

[2NC995]

Im not understanding the drive level differences between the dx500 and the dx1600.

All things being equal, shouldn’t the 1600 take double the drive power, and produce double the output?

Spec sheet shows a dx500 produces 500 watts with 20w input, or 250w with 5w in, and the 1600 produces 1200w with 100w in.

That’s five times as much input for little over double the power?

Would a DX1600 work with 15w carrier, and 45w Pep? How about 40 watts ssb? Are those drive levels just too low? BTW, I’m not actually worried about AM other than not forgetting the amp is on and smoking it, which I would probably do if I ran a 500 and relied on memory to keep the RF dial down.

 

[ExitThirteen]

The 1600 will work just fine with 45W peak on AM and 40W PEP on SSB with no problem, it just won't produce the full output that's advertised. At 45W in, you'll likely get 500-700W out, perhaps a little more depending on your antenna system. You'd be fine if you wanted to go that route.



~Cheers~

 

[2NC995]

Ok, that’s about what I figured from looking at the spec sheets.

The math still doesn’t make sense to me, though. Haha.

People tend to say x amount in per transistor, but these numbers show the two amplifiers behaving very differently with watts per transistor being the same. All things being equal, if DX500V makes 500watts with 20w in, the 1600 should do 1000 with 40w in.

I guess this is what you get with non-linears, haha.

 

[AudioShockwav]

Run the 1600 as 13 has described, put some fans on it and it would be a great combo.
73
Jeff

 

[2NC995]

Yeah, it’s sounding like the best option. I already have a 500 on the way, but that’s how I like to do things...but twice, cry twice.

 

[543_Dallas]

Ok, that’s about what I figured from looking at the spec sheets.

The math still doesn’t make sense to me, though. Haha.

People tend to say x amount in per transistor, but these numbers show the two amplifiers behaving very differently with watts per transistor being the same. All things being equal, if DX500V makes 500watts with 20w in, the 1600 should do 1000 with 40w in.

I guess this is what you get with non-linears, haha.

People like to use the spec sheet and say drive this many transistors with this much. The efficiency of the splitters, combiners and how the transistors are biased have an effect on that. Very rarely are the parameters the same as when the testing was done to write that datasheet. Now that the Toshiba's are gone and were using Chinese counterfeits who knows?

With a Texas star the harder you drive it the more it drifts towards class C. The bias is just good enough to keep it from sounding crummy on ssb. The only advice I have is to not over drive any amp. If you get 100 watts per 2879 that's good enough. If you want it to be as clean as possible shoot for 60 watts pep per transistor.

 

[2NC995]

I drove the snot out of my class c amps in a previous radio life. Now I just want modest power and reasonably clean SSB.

 

[543_Dallas]

I drove the snot out of my class c amps in a previous radio life. Now I just want modest power and reasonably clean SSB.

Me too. My priorities changed. It used to be more important that I could key over someone. Those days are over and I like to rag chew. For rag chewing I want something that sounds clear and be able to talk as long as I want without it overheating.

 

[magnuman]

None of my dx500's did 500w out for 20w in on SSB. More like 500w out for 50w in.

 

[2NC995]

Good to know. Not that I have my heart set on 500w, but definitely good to know.

How much SSB PEP input did you feel comfortable with?

 

[ExitThirteen]

For the DX500, 30-40W PEP max, that'll drive it nicely to full output without hurting it too badly. Personally, 30-35W is good. Make sure you run a fan on the heatsink, and flip the amp "upside down" so the heatsink fins are on top, so the warm air can be drawn up and away from the unit.


For the DX1600, 70-80W PEP would again drive it nicely but keep things running clean and cool. Same thing applies with the fan(s) and heatsink, flip the amp "upside down" so the fins are on top.


Run 'em like that and the amp will outlive you provided your input and output SWR on the amp is good.


~Cheers~

 

[Shadetree Mechanic]

For the DX500, 30-40W PEP max, that'll drive it nicely to full output without hurting it too badly. Personally, 30-35W is good. Make sure you run a fan on the heatsink, and flip the amp "upside down" so the heatsink fins are on top, so the warm air can be drawn up and away from the unit.


For the DX1600, 70-80W PEP would again drive it nicely but keep things running clean and cool. Same thing applies with the fan(s) and heatsink, flip the amp "upside down" so the fins are on top.


Run 'em like that and the amp will outlive you provided your input and output SWR on the amp is good.


~Cheers~

Sounds like my Stryker 955 would be a good match for the 1600. Good to know. I have heard of people running the 500 with the 955, I wonder how crunchy that sounds? I am currently running an Xforce 4 pill with it and does great on AM, on side band not so much. I could hear the side band crunch on my monitor radio (148 with no antenna and headphones) and thought it was RF getting into my rack gear or something at first. Everyone should use a spare radio for a monitor, they might be surprised. My Madison with a DX350 sounds great on side band.

 

[ExitThirteen]

SM,

Your X-Force is likely not class AB biased, so it will not sound good on SSB. That's why it sounds "crunchy". That amp will need proper biasing installed for it run properly on SSB.

Running a Stryker 955 on a DX500 is not a good idea, that's way too much drive for the DX500. You'll also cook the input resistor network that pads the input to the transistors. People who do that are crazy.


~Cheers~

 

[543_Dallas]

Sounds like my Stryker 955 would be a good match for the 1600. Good to know. I have heard of people running the 500 with the 955, I wonder how crunchy that sounds? I am currently running an Xforce 4 pill with it and does great on AM, on side band not so much. I could hear the side band crunch on my monitor radio (148 with no antenna and headphones) and thought it was RF getting into my rack gear or something at first. Everyone should use a spare radio for a monitor, they might be surprised. My Madison with a DX350 sounds great on side band.

I think a 955 with a 1600 would be a nice combination. Having plenty of headroom is always good. With the finals in the 955 I don't believe it should be pushed past 40 to 50 watts pep. If you have a scope I would take it out to your mobile or wherever you are using it and set the radio up to get the best looking waveform out of the amp.

When using a class C amp on AM the drive power is what makes the transistors turn on...for lack of better words. On ssb they are switching on and off as you speak. That in combination with the non linearity of the amp makes it sound like poop on ssb.

I took my big stuff out of my old truck and went back to the old 4 pill xforce. The extra batteries finally gave up and I never drive the truck anymore. Cobra 29 into a 4 pill making a whopping 350 to 400 pep.

 

[AudioShockwav]

I run a old DX 500 at 15/ 20 watts input for 350/380 watts output and I am very happy with that at stock mobile voltage.
Usually if I can hear them I can work them at that level.
73
Jeff