RocketBox HD500 w/9530 FETs

[CB590]

Anyone have any input on these units.

Says can do HD input up to 50w..

Uses Palomar 9530 FET x4

Ratings say upto 25w in with 100w out

Builder says upto 55 amp draw. Has auto SSB like old Palomar units.

Units are $370 shipped. (About $120 less than a TS500HDV..)

Was entertaining for my AT-6666 as it does 40-50w peak.. mainly SSB.

Builder says 50w input for max output and should reach 450-500w.. says AM dk is 2-5w and swing up from that.

They also now offer a 2x4 LD model for $430 or so..

 

[Shadetree Mechanic]

I wonder how hard it would be to turn the 2x4 into a straight 6?

 

[ExitThirteen]

Junk... those mosfets drop output when they get hot, you'll start out at 400-500W, but as you talk on it and the mosfets get hot they will slowly reduce output, talk on it for an hour and you'll only be doing about 250-300W or so PEP. Don't buy one. Seriously.



~Cheers~

 

[jkp1]

I'm kinda getting itchy to try an amp. I'm kinda torn between a Texas Star 500 and an Ameritron 500.

 

[CB590]

I'm kinda getting itchy to try an amp. I'm kinda torn between a Texas Star 500 and an Ameritron 500.

I already had a TS350 and sold it due to truck repair.

I am leaning towards 400-500w myself.. the TS500 is like $475 all day.. the 60-70amp PS to run it is like $180 minimum though..

 

[Tallman]

Junk... those mosfets drop output when they get hot, you'll start out at 400-500W, but as you talk on it and the mosfets get hot they will slowly reduce output, talk on it for an hour and you'll only be doing about 250-300W or so PEP. Don't buy one. Seriously.
~Cheers~

That's the beauty of FETs. They get hot and "Throttle Back" as it were. If your car has a speedometer that reads up to 150 mph are you going to drive everywhere @ 150? One of my bikes had a speedo that read up to 180 mph and I guarantee it never got over 135 on a track.
I would go with the Ameritron 7 days a week.

 

[CB590]

I'm wondering how bad the RocketBox would be for the light SSB aka quick contacts like I do?

I don't rag chew that's for sure.

My # yelling CQ and then waiting.. then a response from say 357.. then me confirming with 357.. maybe a 15 second qso about weather, usually not..

Then a 2-3 minute wait till the next volley..

 

[Tallman]

Probably no problem.

 

[rabbiporkchop]

Anyone have any input on these units.

Says can do HD input up to 50w..

Uses Palomar 9530 FET x4

Ratings say upto 25w in with 100w out

Builder says upto 55 amp draw. Has auto SSB like old Palomar units.

Units are $370 shipped. (About $120 less than a TS500HDV..)

Was entertaining for my AT-6666 as it does 40-50w peak.. mainly SSB.

Builder says 50w input for max output and should reach 450-500w.. says AM dk is 2-5w and swing up from that.

They also now offer a 2x4 LD model for $430 or so..

View attachment 30410 View attachment 30411

First one I saw the input tune was all screwed up. Since they use mismatched mosfets they generate lots of distortion. If they were built correctly they would have lots of potential. Building them correctly means the cost would have to go up I highly doubt he's willing to do that.

 

[Shadetree Mechanic]

So then it's like MFJ products. A project in a box......

 

[Tallman]

Matching mosfets is not critical as bipolars. That amp is just like all of the others.
If you put a garbage in you get garbage out. Radios that have been tuned for "Ghost Watts" will always sound like $h1t. If the harmonic filters have been screwed up the input SWR will be high.

 

[CB590]

I'd entertain the RM 7505v with 4 of the MRF455..

Turn my amp to low power and swing 1-18w on SSB mode with the 6666 into it..

The 7505 is like $210 all day..

Thoughts on that for a choice?

 

[9C1Driver]

I'm kinda getting itchy to try an amp. I'm kinda torn between a Texas Star 500 and an Ameritron 500.

If you go Texas Star look for an older used one in good shape with Toshiba finals. New ones will probably have the HG finals or maybe even the DEI's.

 

[rabbiporkchop]

Matching mosfets is not critical as bipolars.

Probably more critical. They need to switch in unison. They won't if not matched.

 

[Tallman]

Probably more critical. They need to switch in unison. They won't if not matched.

I disagree completely. FET's do not have the negative temperature coefficient like the bipolars. There is very little to match other than the part numbers. The Rds on does not vary much often less than 10%. Most of the time less than 5%. The input capacitance does not vary very much either. The Vgs varies some but with a spread of less than .3 volts it is hard to get fanatical about that.
Using a radio that has been SCREW drivered is more of a problem.
Messing with the harmonic filters for extra output is just plain stupid.