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Rm Italy KL-503 watts vs amps

Some notes from last spring;
Optima @ 10 PEP SSB | 3.8 amps | Dummy Load | Power Supply at 13.8v
MFJ-826B Meter, Megawatt 36s P/S

KL-503
Variable | Amperage Draw| Output
Setting 6 | 32.5 amps | 200 watts
Setting 5 | 30.6 amps | 192 watts
Setting 4 | 30 amps | 185 watts
Setting 3 | 28 amps | 160 watts
Setting 2 | 26.5 amps | 149 watts
Setting 1 | 18 amps | 70 watts
 
My KL203 has an internal 12 amp glass fuse. I'm guessing that it's overrated as to keep from popping fuses all the time. The same could for yours. Of course I keep my 959(no swing mod) on the am side turned down to 1-1 1/2 watts and SSB at 12 watts pep.
try
My KL203 has an internal 12 amp glass fuse. I'm guessing that it's overrated as to keep from popping fuses all the time. The same could for yours. Of course I keep my 959(no swing mod) on the am side turned down to 1-1 1/2 watts and SSB at 12 watts pep.
try a slo-blo fuse with the same amp eating .. just a thought... xxx
 
Year old thread but I ended up getting a few kl-503's. I bypassed the driver. It wasn't getting enough juice to the 8 finals (duh-what the heck). My 2950 drives it very well and despite the power readings being below 250 PEP, the carrier is quite high with 2w input, which I actipually like. Very efficient ever since I got rid of the driver. Honestly, I love this amp. VERY IMPRESSIVE for $150 shipped.

Going to test the 505v now. Hope the 455's hold up.

@CbRadiosPRONTO as the picture on how to bypass the driver and the schematic for the KL-503 posted by @KD2GOE are no longer available in linked thread, do you happen to remember how you did it and maybe a few pictures?
 
If RM Italy says it is a KLV-1000 it will be 400 to 600 watts max on A.M. on SSB peaks up to 650 to 700 watts. In short one half of the model number would be your real watts. It is all just a marketing ploy.
 
the kl503 doesnt put out 450w regardless of what is written.
i have one. 275w is max. and it doesn't sound very good so I never use it. might try the mod suggested above. for RM amps use the rating given as "input" watts and multiply the value by 60% to get the real figure.
KL503 has 9 irf520 type mosfet transistors in a 1 driving 8 configuration. You are limited by the single driver as to what you can put into it.
the amps only redeeming feature is that it is cheap.
there is always a good reason why something is cheap.
Skip over the 503 and get the 505v, which is quite a nice amp.
I’m pretty happy with my 503 , am maxed out about 325 , but sideband locals say audio is funny sounding but the farther they are away the better it sounds, was told to try that mod you talking about, is there any where that has instructions on how to do it????
 
the kl503 doesnt put out 450w regardless of what is written.
i have one. 275w is max. and it doesn't sound very good so I never use it. might try the mod suggested above. for RM amps use the rating given as "input" watts and multiply the value by 60% to get the real figure.
KL503 has 9 irf520 type mosfet transistors in a 1 driving 8 configuration. You are limited by the single driver as to what you can put into it.
the amps only redeeming feature is that it is cheap.
there is always a good reason why something is cheap.
Skip over the 503 and get the 505v, which is quite a nice amp.
I have allway got 250 avg and 400ish peak on my kl503 however just bkew transistors by keying up before remembering i diconnected my anttena due tio lightning.
 
Always take the claims of an electronic manufacturer with a big grain of salt.
Some of their readings are very generous and may have been affected by equipment that is out of calibration, bad test leads, or improper procedures.
 
I repair KL amplifiers and the number one cause of failure is the amps are over driven. The second is over voltage. These are inexpensive amps and usually work well. The promise of 500 Watts from the KL503 is very optimistic.
Tall man please tell me with certainty what get to buy for my kl503 please I'm hearing erf7030 irf520 please tell me I love my kl503 just made a mistake and didnt hook up my antenna after lightning store and transmitted..
 

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