RMS K101 linear

Recently purchased some radio equipment from a silent key and one of the items was the RMS-K101 amp which was in pristine condition boxed and looked as if it was never used,put my cobra 148 inline (12w) switched amp on let it warm up for at least 20 mins in standby then switched it over and started to load it and the most I could load it to 50w on ssb peaking 70w.
Not being very familiar with vacuum tube amps not sure if tube is good so looking for suggestions please.

Hi David,

It's a good single valve linear using circuitry that used to be quite common back in the day.
(We used to take PL509 valves from old Colour TV's to replace them or build our own!)

As with anything shrouded with boastful information I'd say what you're getting is about right if you're reading through a typical watt-meter and antenna. With a sufficient dummy load and peak reading meter you'd probably see much more.

80-100 Watts maximum is about right for these valves with a sedentary life but again people used to push a lot more power into them to get 150W plus or so and slowly destroy the valve. (If pushing them hard a 30 second 50% duty cycle would be apt and usable.)

You could change over the valve if you feel you needed to but you won't be stripping them for free from Colour TV's nowadays. (Valves are flipping expensive today too!) I doubt however you'd see much if any of a difference. There's a good 800-1000 Volt or so on that anode so be VERY careful if replacing it! (Unplug everything!) It should also be mentioned that you can get one hell of a RF burn from such units in operation too.


When used in Radio Amateur HF gear those valves produced their maximum power down at the lower frequencies slowly dropping off as you headed towards 10m. Bigger amplifiers tended to run the valves in parallel for more punch such as the RMS-HT200 and similar linear amps.

That's about as good as I can give you and I'd be happy with them as they'd run all day long like that.  

There may however be suggestion of 'special' replacement valves, tweaks, mods or claims of much higher powers attainable and I'll leave that up to you to decide whether to heed such advice. (Myths especially radio ones die hard. )


At least there's one thing.....it won't suddenly keel over releasing a cloud of smoke should your SWR jump up as you melt the antenna or 'accidently' put more Watts into it!

Plus you get that lovely 'warm' smell that only a valve can produce.


All the best,
Victor

Thank you Victor I will try it on the Icom 718 at 20w which is the input limit and see what difference it makes.

Looking for a 6KD6 valve,if anyone has got one spare for sale as it’s not the EL509/519 valve installed.

Not sure if this will help its a web site that deals in Valves 6KD6
World Tube Company: 6KD6 Tube ( UT ) Valve

Many thanks and on it’s way uk bound.