RM Italy HLA-300 10-160m amp

[Moleculo]

I was talking on 75m with a local tonite who indicated he was purchasing the RM Italy HLA-300 10-160m amp to install in his mobile. Based on the reputation of these amps, I wasn't expecting much but when I looked around for the specs I was a little surprised to find out what it is for the price. It has complete band pass filtering for each band, SWR protection, and achieves 500 watts on SSB with about 20 watts drive.

They're about $400 and you can find them on ebay and other sites. If anybody picks one of these up, let us know what you think.

Here is a link with some good pictures and other details

hla300v

 

[Justme]

They work fine, though 500 watts out is pushing it a lot.

hla300v

Scroll down for the measured output.
Also look into the modification for the improved swr for the input side.

45 to 50 amps is what the amp will need.

 

[bob85]

i have played with/repeired the hla150 and hla300, at the heart of the hla300 is a rmkl500 cb amplifier with large wattage feedback resistors, rm added vswr/overdrive protection plus manual or automatic switched filters but they failed to modify the feedback networks to flatten the gain curve at lower frequencies, the cap and 68ohm series resistor works backwards to what is needed in a hf amplifier,
sd1446's are vhf transistors and have very high gain at lower hf, you should reduce drive on lower bands, on certain frequencies and drive levels you can provoke self oscillation, watch the amp meter for a sudden big jump in current draw,

@13.8v same 60a supply as used in the posted test i saw very similar power figures on the lp-100 and marconi 50ohm load from the sommercamp badged rm hla300.

 

[Captain Kilowatt]

SD1446's are rated at 70 watts output each. That adds up to 280 watts for four of them. 500 watts output? Not likely but 500 watts of power consumption to make that 280 watts out is a reality.

 

[Moleculo]

SD1446's are rated at 70 watts output each. That adds up to 280 watts for four of them. 500 watts output? Not likely but 500 watts of power consumption to make that 280 watts out is a reality.

Look at the graph on the spec sheet on page three. According to this, that transistor will easily do 100 watts at 30mhz. That 70 watt rating is a minium Pout rating, if I read the spec sheet properly.

 

[-=PEAKABOO=-]

Speaking of RM Italy, didn't I see a discussion somewhere about adding thermal tracking to some of the smaller RM amps? If so how are you guys doing this? I get these little amps in for repair sometimes and usually just make them work again but was curious of what the people modding them were doing.

 

[Captain Kilowatt]

Look at the graph on the spec sheet on page three. According to this, that transistor will easily do 100 watts at 30mhz. That 70 watt rating is a minium Pout rating, if I read the spec sheet properly.

That rating is stated for class C operation. Even the test circuit shown is a class C circuit. Notice the lack of a bias circuit? 100 watts in class C at 30 MHz? Perhaps but that is a bit misleading when the claim is for 500 watts out of four devices operating class AB.

 

[bob85]

PEAKABOO, look at the bias circuit, they have two series diodes from the pass transistors base to ground sat on top of the board sniffing fresh air,
if you stick them where they should be under the board touching the heatsink with thermal compound they track reasonably well,
( i like one diode close to pass transistor and one close to a pill right beside it on the heatsink or on the pill cap ) the base emitter junction of two flatpack transistors works well too,
its not perfect but it counteracts the rise in idle current with increasing temparature of both the pass transistor and pills,
feeding the pass transistor with a three terminal regulator and adding a vr to the pass transistor to allow setting idle current on different beta pills is also worthwhile imho,

the palomar v series amps can be easilly tracked by moving two diodes too,

i will be regulating and tracking the bias on a klv550 2pill base amp soon, the stock bias circuit piss poor and sounds like class c on ssb,
i will take some pics if i remember.

 

[mackmobile43]

PEAKABOO, look at the bias circuit, they have two series diodes from the pass transistors base to ground sat on top of the board sniffing fresh air,
if you stick them where they should be under the board touching the heatsink with thermal compound they track reasonably well,
( i like one diode close to pass transistor and one close to a pill right beside it on the heatsink or on the pill cap ) the base emitter junction of two flatpack transistors works well too,
its not perfect but it counteracts the rise in idle current with increasing temparature of both the pass transistor and pills,
feeding the pass transistor with a three terminal regulator and adding a vr to the pass transistor to allow setting idle current on different beta pills is also worthwhile imho,

the palomar v series amps can be easilly tracked by moving two diodes too,

i will be regulating and tracking the bias on a klv550 2pill base amp soon, the stock bias circuit piss poor and sounds like class c on ssb,
i will take some pics if i remember.

Remember me bob? sincerely mack your paltalk friend.

 

[-=PEAKABOO=-]

Normally no one wants great details done to these little amps. I have not had one on my bench in a while I was just curious as to what everyone else was doing. The one I did "tweek" on I just relocated the small diodes to the top of the "pills" I am in the process of redoing the bias circuit I use in my amps so that it tracks heat and current rise a little better.

PEAKABOO, look at the bias circuit, they have two series diodes from the pass transistors base to ground sat on top of the board sniffing fresh air,
if you stick them where they should be under the board touching the heatsink with thermal compound they track reasonably well,
( i like one diode close to pass transistor and one close to a pill right beside it on the heatsink or on the pill cap ) the base emitter junction of two flatpack transistors works well too,
its not perfect but it counteracts the rise in idle current with increasing temparature of both the pass transistor and pills,
feeding the pass transistor with a three terminal regulator and adding a vr to the pass transistor to allow setting idle current on different beta pills is also worthwhile imho,

the palomar v series amps can be easilly tracked by moving two diodes too,

i will be regulating and tracking the bias on a klv550 2pill base amp soon, the stock bias circuit piss poor and sounds like class c on ssb,
i will take some pics if i remember.

 

[bob85]

top of pills works ok for commercial builders,
with the none active pass transistor setup as you will have noticed you get vdrop under higher drive levels even when the pass transistor is fed from a stiff regulated supply, the other problem is as the pass device heats up its conductance goes up pushing bias higher rather than throttling it back, i find tracking both pass and finals helps minimise the thermal drift,

the actively regulated circuit i used based on motorola application notes is much more stable under varying current draw/drive levels but the simpler regulator fed pass setup with tracking is what is found in most hf tranceivers,

good to hear you are still playing with biasing boo

 

[TonyV225]

Its to bad these amps are not built with a little more efforts in certain areas they could be nice amplifiers for the price IF things were setup a little better. I have been tempted to try one of these amplifiers in the multiband HF and VHF models but I dont know anyone personally thats ran one and Ide have to know that they are going to be reliable and most of all they are going to sound good.

I cant get on these ham bands knowing that everyones goingg to say "Hey Tony somethings up with your radio its not sounding so good" hell if you get on 11 meters with a radio or amplifier on SSB thats not sounding perfectly up to snuff they will tell you. There are some very picky people and sometimes sounding ok is just not good enough and they will let you know that is how they feel LOL.

 

[doctor]

RM

As you noticed these RM amps..never mention any warranty at all or what you would do to send in for a warranty repairs...are you stuck with it or what???

DOCTOR/795

 

[TonyV225]

I know there good about answering questions via email Ive emailed them a few times they are actually working on a new 1000 watt fully filtered with a band selctor added HF amplifier I had aquired about recently.

 

[SR385]

hla300v Some nice pics.