Anyones know exactly what this amp is all about ???

[07dodgeram5.9]

https://www.ebay.com/itm/252335744975


I was playing around on eBay and seen this... Any info would be great also seen a few DIY amps what can y'all tell me about these?

 

[357]

Item location:
深圳市, 广东省, China

 

[loosecannon]

it's a linear amplifier that operates on 28 volts at about 5 amps, so you'll have to get a 28 volt power supply in order to run it.

without knowing which mosfets are in it, i can't tell whether their 50 watt claim means 50 watts PEP continuous duty, or if it means that it will do a 50 watt deadkey, which would mean about 200 watts PEP.

either way, it's just not worth the money IMO.
LC

 

[07dodgeram5.9]

Item location:
深圳市, 广东省, China

Chyea Seen that too

 

[07dodgeram5.9]

it's a linear amplifier that operates on 28 volts at about 5 amps, so you'll have to get a 28 volt power supply in order to run it.

without knowing which mosfets are in it, i can't tell whether their 50 watt claim means 50 watts PEP continuous duty, or if it means that it will do a 50 watt deadkey, which would mean about 200 watts PEP.

either way, it's just not worth the money IMO.
LC

I hear ya I was more or less looking for internal amp I could add on... And see that thing

 

[loosecannon]

what sort of setup are you looking to create with the internal amp?

Like, what radio, and what level of output are you looking for?
LC

 

[222DBFL]

An RFX unit might be what he is looking for. Or something of the likes, reading his post topic and post itself. Though not internal they do mount to the back of the radio. Personally I would rather have a separate amp or have the RFX unit made to where if it blew, you could still use your radio. JMHO.

 

[LeapFrog]

RM Italy AD 203 stinger board might be good for what you want. With any mosfet linear be very careful about your SWR

 

[Tallman]

RM Italy AD 203 stinger board might be good for what you want. With any mosfet linear be very careful about your SWR

The AD-203 is prone to oscillation and there is no provision for the SSB switch. The RFX units are the way to go. The fet's blow real easy because you don't have a very good heatsink and then you are also forced to use an external speaker.

 

[Tallman]

It's about $123.48 too expensive.

 

[LeapFrog]

I have a kl 203p, i think it's the same thing as a ad-203 just external and has a housing that doubles as a heatsink, it is so small that it could be bolted right on top of the radio, granted it would cover most of the speaker... I think I paid like $65 while it was on sale. Good little amp for my experiments. I have heard this 10 meter amp will key on 11 meters but I cannot & will not confirm. (It has a "wide" range of frequency coverage)

I wonder if this amp is going to oscillate on me or give me problems, the relay only clicks to activate the unit when the radio is keyed. Has a pre-amp too if you want to hear the noise floor louder. Sometimes the pre-amp can help pull in a distant station that otherwise would not have been heard through the static.

If its for a cb the carrier will have to be lowered, one could add a diode inline to the one leaving the modulation transformer if it's that type of radio (Most cobra mobiles). Also check your countries regulations first, I cannot recommend something that may get you in trouble...

 

[Tallman]

I have a kl 203p, i think it's the same thing as a ad-203 just external and has a housing that doubles as a heatsink, it is so small that it could be bolted right on top of the radio, granted it would cover most of the speaker... I think I paid like $65 while it was on sale. Good little amp for my experiments. I have heard this 10 meter amp will key on 11 meters but I cannot & will not confirm.
The speaker is removed from the radio and the amp is mounted on the lid where the speaker was.
Yes it will key on 11 meter.

I wonder if this amp is going to oscillate on me or give me problems, the relay only clicks to activate the unit when the radio is keyed. Has a nice pre-amp too if you want to hear the noise floor louder. Sometimes the pre-amp can help pull in a distant station that otherwise would not have been heard.
All amplifiers can and will oscillate under the proper conditions.
The pre-amp is not selective and amplifies everything including noise. I have personally have not seen it be of any benefit.

If its for a cb the carrier will have to be lowered, one could add a diode inline to the one leaving the modulation transformer if it's that type of radio (Most cobra mobiles). Also check your countries regulations first, I cannot recommend something that may get you in trouble...

It is recommended that you dead key with only 2.5 watts or less.

Expand the text box for the full reply.

 

[LeapFrog]

Sometimes making the static & atmospheric trash louder can help here that distant station, I agree the pre-amp will definitely amplify everything not just other radio signals.

I wouldn't hesitate to buy another one though, they are sen as disposable amps but they can be repaired if the mosfets blow out. Cheap IRF520's can be used as a replacement mosfet, or one can order the originals directly from RM Italy.
(I am unsure what they really use, i think the part is a common mosfet but re-labeled to say something like rm3)

 

[Tallman]

Sometimes making the static & atmospheric trash louder can help here that distant station, I agree the pre-amp will definitely amplify everything not just other radio signals.

I wouldn't hesitate to buy another one though, they are sen as disposable amps but they can be repaired if the mosfets blow out. Cheap IRF520's can be used as a replacement mosfet, or one can order the originals directly from RM Italy.
(I am unsure what they really use, i think the part is a common mosfet but re-labeled to say something like rm3)

If you want to buy factory replacement parts you need to contact DNJradio or H&Yelectronics.

 

[222DBFL]

07dodgeram5.9, you migh want to look at something more like this if you are trying to add some extra power to the radio itself and not have a separate amp per say. Meaning having a seperated unit from the radio itself. The RFX 150 will give you a good boost in power and they don't cost a whole lot. You'll need to have it installed, and I would have a reputable tech do this!! Here is what I am speaking of and the specs. They also make smaller versions of this unit too, so don't let the size of the larger RFX150 steer you away. I am not sure as to how or if you can wife one of these to make the radio work if it should fail. But anything is possible I suppose if you try hard enough.
Mind you, like I stated above, if you wire this directly to the radio with no on/off or bypass switch so that if the RFX unit takes a dump, you can still keep using the radio at least, that is if it's not burnt up as well. I will say that these units that I am speaking of don't like a high or bad vswr. Keep it under 1.3:1 VSWR (SWR), and they will work well. Also don't crank the power to the max and add a fan set to the back of them. Here are the pics I promised of the units and some that are mounted. And also they do make these RFX units in different sizes. Or power levels I should say. Hope this helps. Good day.
I am sure many will say to just add an external amp and I agree with that as well. But some people just can't do that due to moving around a lot or no amps in the work truck. Separate ones anyhow. Now if this is for your personal radio at home or mobile for your own vehicle, skip the RFX units and get an external amp for sure. I have heard many a people on 38lsb talking on a kl203p and they sound fine as long as the amp isn't overdriven. Anyhow. JMHO,S. Again good day.