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RM kl503 or RM kl405v
- Thread starter Sandpile
- Start date
I would not choose either one of those.
It has two things wrong with it, "RMI" and "KL".
I guess that is not really a fair statement on my part. I worked on so many RM Italy units that had blown transistors in them. Some were infantile failures others abused by the user. Infantile failures are transistors the fail because they were compromised either during its manufacture or ESD damaged or some other failure mode. But usually overdriven by the user.
If RMI really had their stuff together they would not have built amps with such a low drive requirement.
It has two things wrong with it, "RMI" and "KL".
I guess that is not really a fair statement on my part. I worked on so many RM Italy units that had blown transistors in them. Some were infantile failures others abused by the user. Infantile failures are transistors the fail because they were compromised either during its manufacture or ESD damaged or some other failure mode. But usually overdriven by the user.
If RMI really had their stuff together they would not have built amps with such a low drive requirement.
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I should of said in my first post, I'm based in the UK and intended use would be freeband ssb and very occasional FM use from my base station Kenwood ts570d through the siro827. I currently run a kl203p mobile and it's great! mainly FM use with 4w in it gives me 60w out, for all sceptic's it's served me very proud for last 2years and a bargin at £38 new, thanks all
It's just the price that isn't at £280 for the kl505v. I can buy either of the others for £150 which is more relastic for my budget.
So whys a kl505v better than a kl503? What's the difference? Apart from fans and more suitable power cable and possibly few extra watts?
So whys a kl505v better than a kl503? What's the difference? Apart from fans and more suitable power cable and possibly few extra watts?
The 503 is 1 driving 8 mosfets like two kl203's combined,
they use cheap switching fets that are not designed for rf amplification and are far from linear but they work if making more power on the cheap is all that matters to you,
the 405 is a 2 transistor bipolar amp with an active regulated & thermal tracked bias circuit, use proper RF transistors,
they are linear up to 90 / 100w
the 505 is two 405's combined, linear up to about 180w,
The farty little fans RM hack into the heatsink fins won't keep them cool,
putting 2 & 3 farty little fans fighting each other on an amplifier is stupid but it sells more amps,
when a no fan version is available its the better choice, fit your own 120mm fan,
the power sockets on the newer amps are just eye candy like the silly fans.
they use cheap switching fets that are not designed for rf amplification and are far from linear but they work if making more power on the cheap is all that matters to you,
the 405 is a 2 transistor bipolar amp with an active regulated & thermal tracked bias circuit, use proper RF transistors,
they are linear up to 90 / 100w
the 505 is two 405's combined, linear up to about 180w,
The farty little fans RM hack into the heatsink fins won't keep them cool,
putting 2 & 3 farty little fans fighting each other on an amplifier is stupid but it sells more amps,
when a no fan version is available its the better choice, fit your own 120mm fan,
the power sockets on the newer amps are just eye candy like the silly fans.
In that case the 405V for sure.
The fans work fine for me..better some fans than no fans.
I have seen way too many problems with the 503 over driving that single driver transistor and I am not even sure that driver is particularly linear. The 503 would be a lot better had they had just dropped the driver all together and feed the 8 little mosfets in parallel. I am sure it would sound a lot better on air and last a lot longer.
The fans work fine for me..better some fans than no fans.
I have seen way too many problems with the 503 over driving that single driver transistor and I am not even sure that driver is particularly linear. The 503 would be a lot better had they had just dropped the driver all together and feed the 8 little mosfets in parallel. I am sure it would sound a lot better on air and last a lot longer.