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Discussion in 'CB and Export Equipment and Accessories' started by jbenally33, Apr 7, 2009.
However the specs look practically identical:
Anyway, if you want to go the FET route, you can use the ERF2030 for 25-30 watts or the IRF520 if you want 40-50 watts.
Once had a tech look in my radio (that wasn't bought from him) and remark that it had 2312s which to him indicated the manufactorer used a better quality of components when building the radio. He stated individually the 2312 transistor's performance was not that much greater than a 1969 to notice the difference, however in his opinion they would outlast a 1969.
Just as some today will argue while a MOSFET may get you more watts on the meter it may not have as clean of audio and may be more prone to intolerance resulting in failure.
What it all boils down to is; who is tuning the radio and how much they attempt to obtain with regard to component limitations.
Something is fishy about these numbers:
Collector Power Dissipation (TA = +25°C), PD 1.7W
Collector Power Dissipation (TC = +50°C), PD 20W
That 1.7 watts looks wrong, maybe they mean 17 watts dissipation.
Or maybe they mean 1.7 watts without a heatsink. who knows.
My Cobra 29 LTD Classic swings 30 with original final
I did some mods to my Cobra 29 (1991) but never changed the final simply because I didn't have a 1969 handy. I set mine up for a 2 - 3 watt DK with a normal swing of 25 - 30 watts.
What are the mods that people use to get the 45 - 50 watts out ? As far as which final is better, the final alone will not give you more output will it?
I mean if you can't drive it any harder you can't expect a whole lot of improvement can you?
On that mod, some of the steps are more about audio characteristics change than the power output. Regardless, I every time I do one of these radios and put it on the air the locals say it sounds great.
The other way to do is is to use the IRF520 FET as the final and do the appropriate mods for that.
Before I was allowed to touch the good stuff I did a lot of CB's.........I prob. " peaked and tweaked 500 Uniden Grants and CObra 148's for instance around this time in the early 1990's. I could routinely get 26-36 watt's of nice clean power on SSB out of either of the Uniden or Cobra's mentioned above.....The dual final RCI's could never match the power output on side band of the single final Cobra or Uniden well not stock out of the box at least"regulator issues" that is another story though. My dual final 1st gen RCI 2950 23 clean watts on SSB I can still recall how disappointed I was my friends Cobra 148 had more power on SSB. I prob. realigned that radio 5 times that night and could not get it above 23w. I give it to my boss keep in mind back then HRO sold the 2950 for $495 he got ready for it 23w's!!!
The only reason 1969's kind of get a bad rap for durability is people over biasing them for a few more dirty nasty watt's. Heat soak climbs fast as you over bias a transistor and sound quality and inter-mod deteriorate quickly and it's ability to survive SWR spikes like wise starts to drop. I do not have access to how this transistors behaves as the heat climbs but unless designed to deal with lots of heat few transistors really behave well as you heat them up beyond their initial design specifications. No one says " I am going to design a transistor to be an RF final that Rednecks can't easily kill even over biasing them in Gerogia and Texas Heat and sending harmonics and large swinging power spikes through day in and day out from their hot car or truck!" LOL!!! So really the 1969 impressed me from the stand point of taking more abuse then the designer could have ever predicted it would need to take!
To get any better I would want to see more gain at the same power output etc..........This way you could turn the power down let the added gain do it's job and run the componet cooler for longer life. If it had vastly better intermod I could see calling them better as well but I just not see it. Just opinion mind not like I was out testing 5000 of these to put trending data together.
A Pair of matched Mitsi 1969`s can still be had, but it is going to cost you, RFParts in San Marcos CA still has them for $31.90 a pair, And they are the only ones I would trust to sell you a true Mitsi Part.
Almost everything else you find on-line now days is some re-branded Chinese fake.
Durham radio up in Canada "might" have some left, don`t know, they are also trustworthy.
There is a replacement called a CB-20 made by Eleflow, as far as I know there only distributor is a gentleman that goes by weazle66 on E-bay and the cost is about $6.50 each.
To make it worthwhile you need to buy a dozen or so to bring down the cost of shipping from ($13.72) the UK, cost`s him the same to ship one or a dozen.
I have got a few eleflow transistors from him and they are all good (2166 & 2312's) for my gen 1 rci 2950. He also sells a mrf477 by eleflow which will be my next purchase to fix up my old 2510