YouTube - CB RADIO FINAL COMPARISON
well, if he cant make it work; it must be impossible right? LMAO!
LC
well, if he cant make it work; it must be impossible right? LMAO!
LC
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dispelling myths or lack of knowledge? LOL
- Thread starter loosecannon
- Start date
When changing a final in a radio, it's not the wattage or collector dissipation that indicates if the part will make more power then the original. It is the gain of the part at the operating frequency that determines this. The data sheet for the 2SC2078 and 2SC2166 shows 13.8 db while the 2SC1969 is lower at 12 db. Unless you find a way to increase the driver output, the 2SC1969 is not going to make more power in the final stage of these AM only radios.
What you do gain with the 2SC1969 final in these radios is durability. Since the transistor will never be driven to it's full ratings, this makes it more rugged in the application. More power output requires at least one, usually two of the following. More drive, more gain, more current, or more voltage. None of these happen when replacing the stock AM final with a 2SC1969.
What you do gain with the 2SC1969 final in these radios is durability. Since the transistor will never be driven to it's full ratings, this makes it more rugged in the application. More power output requires at least one, usually two of the following. More drive, more gain, more current, or more voltage. None of these happen when replacing the stock AM final with a 2SC1969.
So much for this guy doing a honest comparison of the 2 transistors, he actually has his comments section set to "approval by owner" so he can censor any and all information dispelling his "proof" of said transistors being no different than the other.
Despite him being an "IDIOT" he is also a crook.:tongue:
Despite him being an "IDIOT" he is also a crook.:tongue:
Exactly. I have known a lot of guys that thought changing the finals or amp transistors to something speced for more power output would actually give them more power output. If the gain is the same for both parts the output will be the same unless you can drive it harder. Sometimes replacing the driver with a higher gain device and then changing the final will indeed get you more power out but the difference over stock is hardly worth the time, effort, or expense.
my point is that there is more to it than simply swapping one transistor for another.
i refer you to this thread:
http://www.worldwidedx.com/radio-ra...bra-29-high-power-mod-2sc1969-transistor.html
i did this mod a while ago and was able to get a 10 watt deadkey with 40-45 watts of swing.
i did not run it this way but the radio would do it.
no, i did not look at the signal on a scope or a spec analyzer, i was just using the same type of wattmeter that is in the youtube vid.
with the stock driver and final combo i was only able to get about 25 watts PEP.
i do not claim to know all the why's and how's, but i do know a 1969 final with 13.8 volts on the collector will do more than 15 watts on a dosy meter.
i do not think his comparison shows what he thinks it shows; i think he is trying to drum up business by bashing other shops.
LC
i refer you to this thread:
http://www.worldwidedx.com/radio-ra...bra-29-high-power-mod-2sc1969-transistor.html
i did this mod a while ago and was able to get a 10 watt deadkey with 40-45 watts of swing.
i did not run it this way but the radio would do it.
no, i did not look at the signal on a scope or a spec analyzer, i was just using the same type of wattmeter that is in the youtube vid.
with the stock driver and final combo i was only able to get about 25 watts PEP.
i do not claim to know all the why's and how's, but i do know a 1969 final with 13.8 volts on the collector will do more than 15 watts on a dosy meter.
i do not think his comparison shows what he thinks it shows; i think he is trying to drum up business by bashing other shops.
LC
Someone took a lot of time to figure out the best way to do two main things. First, lots of work has been done to the driver stage and coupling to the final to get more drive into the 2SC1969. Second, he took the time to lower the output impedance by reducing the inductor value in the output stage to realize the increased power at the same voltage.
You must admit this is a good deal of work to do right and the problems with buying the obsolete 2SC1969. There are also issues with trying to pull the current required to produce 45 watts PEP trough the same DC chain that was only designed to provide about 2 amps.
Both the RF choke and DC choke feeding the final VCC are too small for the job. Some attempt is made to compensate with the 3300 uf cap but that's just a bandaid. Point being if you had to pay a qualified technician to do this work, you would be better off buying a one transistor amplifier.
To be fair, I have to agree with Loosecannon. This guy is trying to hide any benefits that could be achieved with some extra work here. Upon close examination you'll see he didn't even retune the "27 MHz slug" as he calls it. More power at the same DC voltage requires compensating for a lower output impedance too.
You must admit this is a good deal of work to do right and the problems with buying the obsolete 2SC1969. There are also issues with trying to pull the current required to produce 45 watts PEP trough the same DC chain that was only designed to provide about 2 amps.
Both the RF choke and DC choke feeding the final VCC are too small for the job. Some attempt is made to compensate with the 3300 uf cap but that's just a bandaid. Point being if you had to pay a qualified technician to do this work, you would be better off buying a one transistor amplifier.
To be fair, I have to agree with Loosecannon. This guy is trying to hide any benefits that could be achieved with some extra work here. Upon close examination you'll see he didn't even retune the "27 MHz slug" as he calls it. More power at the same DC voltage requires compensating for a lower output impedance too.
He should try driving the 1969 with that 2166 then he would see phenomenal outputs frum his sevondie siiiix.
shockwave you are absolutely correct about the amount of work involved, and the cost as opposed to just buying an amp.
the reason most people would get this mod done would be to drive the snot out of their amp for more power on the wattmeter.
regardless of what we know about doing this, lots of people want to do it, and that is their prerogative.
snakeradios is a hack, and gets his "tech info" off the net from forums like this one.
he is playing on the naivety and inexperience of the youtube crowd, and trying to gain business by downtalking other shops when he is the one who doesnt understand whats going on. LOL
i just think the buying public should know, thats all.
LC
the reason most people would get this mod done would be to drive the snot out of their amp for more power on the wattmeter.
regardless of what we know about doing this, lots of people want to do it, and that is their prerogative.
snakeradios is a hack, and gets his "tech info" off the net from forums like this one.
he is playing on the naivety and inexperience of the youtube crowd, and trying to gain business by downtalking other shops when he is the one who doesnt understand whats going on. LOL
i just think the buying public should know, thats all.
LC
- No one is chatting at the moment.
