What are the best trans.for a RM KL-203P AMP ???

A forum for the discussion of matters of a technical nature. All such activities are undertaken at the readers discretion and own risk. If you don't know what you are doing, don't blame us if it all goes wrong!
Post Reply
User avatar
WARLOCK
Top Poster
Top Poster
Posts: 1414
Joined: 04 Jun 2008, 08:27
Call Sign: 26TM134
Location: cambridgeshire

What are the best trans.for a RM KL-203P AMP ???

Post by WARLOCK »

Having blown my RM KL203P amp can anyone put forward some better more powerful trans, ???
User avatar
Mudslinger
Legend
Legend
Posts: 7483
Joined: 28 Jul 2010, 07:11
Location: Oxfordshire

Re: What are the best trans.for a RM KL-203P AMP ???

Post by Mudslinger »

Not sure about more powerful but knights did list the original RM3's.

I think you can use IRF520's as well.
Mudslinger - Simon
26TM274
26CT612

There is no such thing as a Fidelity 1000 which is too good to scrap.
speeddemon

Re: What are the best trans.for a RM KL-203P AMP ???

Post by speeddemon »

Hi warlock use irf520's and don't overdrive them ie 5watts max am/fm Input to amp gd luck . Cheers n'73's
User avatar
listner132
Radio Addict
Radio Addict
Posts: 618
Joined: 28 Mar 2009, 11:27
Location: Ayrshire Scotland.

Re: What are the best trans.for a RM KL-203P AMP ???

Post by listner132 »

I have changed the fets from the origonal rm3 fet i have tried both fqp13n10,s and also irf520's both replacments work ok but the power is about 30 watts less that what it was with its origonal fets..
The Collector
Legend
Legend
Posts: 8666
Joined: 23 Jan 2010, 19:26
Location: Bristol-ish

Re: What are the best trans.for a RM KL-203P AMP ???

Post by The Collector »

I read something identical to this somewhere else just yesterday. Someone said they were probably poor, cheap replacements and someone else saying the bias needed tweaking to get better results whatever that is if it has one???

Try searching on this site to see if there's relevant info available.

dt307 may be the chap to contact as I think he's good with amp's ;)
User avatar
dt307
Top Poster
Top Poster
Posts: 1250
Joined: 05 Sep 2014, 16:15
Call Sign: 163dt307

Re: What are the best trans.for a RM KL-203P AMP ???

Post by dt307 »

https://www.moonraker.eu/rm-mospower-rm3 not realy expensive less than a tenner to get the amp backup and running at correct power levels and the correct transistors.
fqp13n10 work fine but power is down to about 110w i fit theese because i have loads
https://www.mouser.co.uk/ProductDetail/ ... aoQAvD_BwE
or send me a pm and i post you 4 free .....not exactly gonna kill me or leave my self short
if5520n the "N" is for Never gonna sound good .....if you must use the irf520 non n
BTW save your self some pain if you dont have the skills/tools to remove the old ones correctly.
snip the old fets off at the body of the transistors and solder new ones directly to the legs of the old ones.
or if you must unsolder them same snip off the transistors at the body and unsolder 1 leg at a time and if there is any solder in the holes run a hand drill through them
https://www.amazon.co.uk/FOCCTS-Holding ... 0654&psc=1
163dt307-chris




“I fear the day that technology will surpass our human interaction. The world will have a generation of idiots.”
― Albert Einstein
pienari
Regular
Regular
Posts: 44
Joined: 18 Feb 2017, 13:05
Call Sign: 56la422
Location: Finland
Contact:

Re: What are the best trans.for a RM KL-203P AMP ???

Post by pienari »

I have tested several different fets and 48w IRF510 or IRF520 works. 520 less power then 510.
IRLZ14 and IRLZ24 works fine.

I have build diy fet amp 2drive 16fet @27v same fets and it work great.
Image
Paljon pilalle tinailtuja koneita. ;)
Mobile. Ham concorde3, Megawatt 4000,Zetagi B550p.
Home. Colt Excalibur SSB , 2el Quad, Diy ldmos amp 1.6kw pep.
User avatar
Unit 148 Mobile
Super Member
Super Member
Posts: 125
Joined: 24 Sep 2010, 20:50
Call Sign: G4ZOW
Location: Limassol, Cyprus
Contact:

Re: What are the best trans.for a RM KL-203P AMP ???

Post by Unit 148 Mobile »

Pienari,

Tell us more about both of your homebrew amp's the 16 fet unit and the 5kW one in your profile?

I have a US made 16 x Toshiba (originals) 2SC2879 mobile amp that runs luke warm at 1500W pep out and can easily run 2kW+ with a stiff 16V power supply.

Unit 148 - G4ZOW
pienari
Regular
Regular
Posts: 44
Joined: 18 Feb 2017, 13:05
Call Sign: 56la422
Location: Finland
Contact:

Re: What are the best trans.for a RM KL-203P AMP ???

Post by pienari »

Yep its not 5kw,maybe i have to add 0 before ,5kw.
So that 2+16fet amp output is 500w dead key 10w drive and 1kw pep ssb @27.2v.
Boards are my own desing and build.
I got option to chance 2+20fet boards later.

I bought burned kl-503 and all fets was burned.
Maybe i mod this unit to 24v.
Paljon pilalle tinailtuja koneita. ;)
Mobile. Ham concorde3, Megawatt 4000,Zetagi B550p.
Home. Colt Excalibur SSB , 2el Quad, Diy ldmos amp 1.6kw pep.
Post Reply