thinking of buying the texas star DX500 http://www.texasstar.com/500Vxmtr.html ,wondered if anyone on here has one?,have been in touch with the company that sells them and here is the email i received from them:

Subject: Re: sale enqiry


DX500V
Input power up to 50-60 Watts.
Multiplication factor is 10 to 1 so 40 in 400 out and 60 in 600 out but 50 watts and 500 out she will last forever. Al these on a good PEP meter not average power which will be about half or less.
Watch the SWR and all connections as 500W will cook a poor joint.
You will need 60 Amps plus of 13.8 to 14.5 volts DC.
All amps need a fan.
Don't run it too long or too high in AM/FM cos it will get hot.
Max AM input 25W.
Price is US$350 plus courier fee.
If you are going to run this amp mobile you have to set it up carefully.
It won't work good with a mag mount!
It will do funny things to your cars computer.!!
500 watts is a lot of grunt.
The models we sell are High Drive and are factory converted to work without any further modifications as they were made for us especially by Galaxy(They own Texas Star) for export.
Can't buy them like this in the US and the shops will charge you a further US$50 or so to modify them so they will work as an amp and not as a CW transmitting toy.
Do not use the variable resistor to control the power output but reduce drive to the amp from the radio.

Rgds,
Dave

thats the email above that i received from the company selling them,anyone got one? or have any opinions on it?.

a local has one, they use 4x 2sc2879 transistors, 7w fm input gives 400w fm output on a bird43 meter, more if you drive it harder,
they run hot so need cooling if you want it to last for years, i would recommend a medium to high flow 120mm fan mounted close to the fins and blowing onto the heatsink.

cheers for the reply wa10.

hey m8 just got this email from a company that sells these DX500V LINEAR AMPS,he reckons you need 2 40 amp psu,s to run this amp to its maximum.
i suggested a 60 amp psu to him and he said no use as it would keep tripping out.

heres the email:
Cheaper than buying 1 large one to run it with...Just uses one more set of wires..RM psu has a 13.8 switch so both are locked on 13.8.
Not as hard as it sounds.
I had 4 diamond 40 amp supplies feeding my 1 KW amp for years with no problems.
Best do it right first off so no troubles later on...You will trip a 60A supply with the DX500 enough times to **** you off.
It is effectively almost twice as strong as the KL500 and sounds better.
But it only works on 10-12m
KL500 is quite broad so not optimized higher up like the DX500.
Power out means power in+++
Don't trust the power/swr meter. Go off the amps and voltage and efficiency to get true power out.
2 40A supplies cost about the same as one 60A or they do over here!
So for price I reccomend the 2 ea 40's which gives lots of headroom for when you start pounding it..as you will!
Do you have a good SWR meter that can handle 500W?
The increase in power can cause things that are not up to snuff to burn up and part causing the line to go open and you will kill the amp in short time if you are not watching things.
I always monitor the SWR with these amps.
If you see the SWR start creeping up as you use it then something in or on the end of your coax is getting hot....
Just want you to be aware that there is a downside to running hi power. Some antenna's can not take it! Specially those with coils.
The DX500 is a serious amp despite the size. I would not be saying these things if you were buying the KL500 because it doesn't have the grunt of the DX500.
rgds,
Dave


what do you guys think?,seems bit weird to be using 2 40 amp psu,s to run this linear?.

not ideal but it works, both supplys should be the same type and set to exactly the same voltage otherwise one psu will be doing all of the work untill the current limit kicks in and folds back the voltage bringing the other into play, if you use large isolation diodes in series with the positive from the psu's it works ok,
not using isolation didodes is a recipe for potential disaster
i know a guy in australia that uses a bank of 20 x 40 amp switchmodes isolated with diodes to run a 24 x 2sc2879 amp,

once you go larger than a kl500 things get expensive

any more info on the large isolation diodes in series, i,m a bit lost there m8.

connect your power supply negative leads and the amp negative together,
get a couple of large stud style diodes, screw them into a heatsink and connect the red+ from each power supply to a diode, connect your red power lead from the amp to the heatsink, you will get some volt drop across the diodes but you can usually up the power supply voltages a little to compensate if it bothers you, done that way you are pretty safe even if you dont turn the supplys on at the same time,
i would use a minimum of 100amp stud diodes larger if you can find them,

Be like here, got a fatboy amp and that needs 3x lorry batteries to make it work. Luckily sold it to a trucker and now he makes a mess with it

why do you need so much power?

May I ask what antenna you will be running?

well because i was told i need 2 40 amp psu,s to run this DX500V linear to its maximum,the 2 40 amp psu,s will consistently feed the DX500V linear the ampage it needs to run at its max.

i,m using a antron 99 so no worrys there.

wa10 where can i buy 80 amp stud diodes?

you can buy them from farnell but they aint cheap http://tinyurl.com/3r3vso
you need stud cathode types, the larger diodes you use the less volt drop across them at high current, bigger is definately better here,

i have never bought any, i remove them from big power supplys/industrial battery chargers or search ham rallys, its surprising what you can find if you keep your eyes open when your riding about, i once spotted a beaten up garrage charger/jumpstart with some other junk in a farmers gateway, fly tippers eh,
i rescued 4x 300amp stud diodes on 2 nice heatsinks,

good luck.

seems like a hell of a lot of hassle for 3db increase over the biggest amps here in the uk.not a lot of signal increase for a hell of a lot of money.especially if you don't have an antenna up to the job with sufficient grounding to avoid rf feedback.also as the antron 99 power handling capabilities are almost as certainly overexagerrated as its gain i sense trouble looming ahead,coax would have to be pretty decent too.not to mention the fact if everything isn't spot on the amp will selfdestruct at the first sign of high swr,poor soldering,will be costly to repair too.then theres the potential rfi,power levels like that aren't exactly neighbourhood friendly unless you know exactly what your doing.with all due respect a statement like" i,m a bit lost there m8" doesn't suggest that is truly the case.just an honest opinion.good luck if you do decide to choose that path.

incidentally a 3 element beam/processor combination would probably give you a bigger reward with a lot less hassle or problems.

its only 500 watts or so and the antron99 would handle that no problem,also i,m using rg213 coax,so there should,nt be a problem there either.
swr is grand on 11 meters and its only on 11 meters i would be using the DX500V linear.

i don,t think one needs diodes anyhow to run the amp.

would a 8 element cubicle quad beam with 42 ft boom be a better option?.

Yes. By a long way!