RM Italy KL 503 HD - Anybody ever use?

[Wire Weasel]

I'm considering the RM / KL 503 HD. Anyone here have any experience with these and what do you think of them? Thanks !

 

[Tallman]

I repaired one once. Person pumped 100 watt dead key in to it.

 

[Tallman]

It appears to be well made unlike some of their other product.

 

[KD2GOE]

hmmmm HD? so i am guessing they removed the Predriver that made SSB sound like CRAP!

 

[dave457]

The ssb sounds like crap out of this amp

 

[CB590]

The ssb sounds like crap out of this amp

Would that be the regular 503 or this HD flavor?

 

[kopcicle]

Would that be the regular 503 or this HD flavor?

Yes

 

[magnuman]

The early KL503 ones were terrible with that silly unbiased driver transistor.
The HD ones might be better if all 8 are fed together but not at 300w.
200 watts PEP would probably be a cleaner output.
But the proof is in the pudding!
Who has one of these new ones?
How is it?

 

[Robert Cook Sr]

I'm considering the RM / KL 503 HD. Anyone here have any experience with these and what do you think of them? Thanks ! View attachment 30437

nice linear, been using for 1.5 years on base and in my truck,88 Radio says they are back in stock .,ordered another today 4/27/2023

 

[Robert Cook Sr]

The early KL503 ones were terrible with that silly unbiased driver transistor.
The HD ones might be better if all 8 are fed together but not at 300w.
200 watts PEP would probably be a cleaner output.
But the proof is in the pudding!
Who has one of these new ones?
How is it?

Been using for over a year now on base and mobile HD version no problems except 2 in truck lost preamp but linear still works great . puts out 250-300 with 35 watts PeP ,using 5555N11 radio with around 8 watts dead key.

 

[Wire Weasel]

Old Thread. Actually made a buy a couple of months ago - was still considering the 503 but the only Usual Suspects Dealer that carries them was Out of Stock. They did have some 703's so took one of those. Extremely happy with it.

 

[BigLou]

I have the 503 it,s my backup now worked good on SSB every one liked it . I now have the 703 same report on it to. The 503 will do 200 all day. Good amps for the money

 

[Holydvr]

I likely will not ever own one. But, some locals out where I live run them and they do well as long as they are not overdriving them. For awhile some were trying to wring every watt they could get out to of them it seems and would distort some and they would bleedover. It seems they have all settled down now, backed the input and audio down and they seem a much better amp than I initially thought!

 

[Greg T]

One of my buddies has one. Sounds like garbage regardless of how you drive it. SSB is even worse.

 

[Robert Cook Sr]

One of my buddies has one. Sounds like garbage regardless of how you drive it. SSB is even worse.

Been using for 2 years,a very good linear if used correctly, well built, used the KL503 firsts then the KL503HD drive with a 5555N11 at 35 watt PtoP power and it sounds great to every one I talked with. P-P watts 225-300 watts and Dead key around 8 watts with KL503HD using 503 use 1.5 to 2 dead key and no more than 10 watts PtoP watts