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Deadkey vs swing

1342 said:
that amp should do between 180-250 watts average power you should be close to target.toshiba transistors are underrated and 2290 are closer to 80-90 watts give or take depending on input and voltage supplied.it sounds like its doing a good job as is.
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359 said:
I'm not EVEN touching that one :LOL:
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i will .
its CB bullshit .
but i guess 1342 knows more about what the 2290 will do than the folks that did the R&D and then the manufacturing of it . but don't believe me or anyone else . heres what Toshiba has to say about their product . take note that it is rated as a 60 watt PEP , PEP , PEP , PEP .
by the way , did i mention its rated with PEP watts ...... not average ?

http://www.rfparts.com/pdf_docs/2SC/2SC2290.pdf

just because it can do more doesnt mean it should be run that way .
your car will probally do 100+ MPH , how long do you think it would last on the autobahn doing 150 mph all the time ?
 
BOOTY MONSTER said:
i will .
its CB bullshit .
but i guess 1342 knows more about what the 2290 will do than the folks that did the R&D and then the manufacturing of it . but don't believe me or anyone else . heres what Toshiba has to say about their product . take note that it is rated as a 60 watt PEP , PEP , PEP , PEP .
by the way , did i mention its rated with PEP watts ...... not average ?

http://www.rfparts.com/pdf_docs/2SC/2SC2290.pdf

just because it can do more doesnt mean it should be run that way .
your car will probally do 100+ MPH , how long do you think it would last on the autobahn doing 150 mph all the time ?
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thanks booty that graph at the bottom left corner shows about 85 watts hmm.damn i have seen 2 pill 1446 amps do more that 120 watts with 4 watts input.
 
you're welcome 1342 .

if you look at the output power graph beside the input power graph that you mentioned you will notice there is a inter-modulated distortion graph . @ 60 watts the IMD is about 30 db down . beyond that it is steadily rising . it doesn't get lower beyond that point , it continues to have increased IMD with more power output . so yes it can do more than the rated power spec , but as it does so the more output that it does the more distortion is in our signal .


now , if the pills were pink instead of white it would be a different story .... but ill let the crotchety old bastard explain how that works .
^5 doc. ;)
 
but i guess 1342 knows more about what the 2290 will do than the folks that did the R&D and then the manufacturing of it . but don't believe me or anyone else . heres what Toshiba has to say about their product . take note that it is rated as a 60 watt PEP , PEP , PEP , PEP .
by the way , did i mention its rated with PEP watts ...... not average ?
Click to expand...
Lets revisit the thread about the 2sc2879 for a minute, I believe it has already been shown by W8JI that the test set up used for the Spec sheet is not optimal, and in fact the 2879 can indeed produce more power than the single limited test jig has shown at 12.5 volts.

Just out of curiousity I bolted up a single 2SC2879 in class C (zero bias) in a single ended amplifier with resonant transformer. Heatsink is massive and I used a soft copper gasket for better heat transfer, no grease.

On 5 MHz I can easily push it to 30 amps Ic at 18 volts and get almost 300 watts output. At about 30 amps my supply shuts down. I didn't filter the output beyond the resonant transformer but the 2nd harmonic was about 15 dB down and 3rd harmonic much less level than that. Harmonics were pretty much gone after the third. The harmonics clearly contribute less than 10% to the output measured.

The statement a single 2SC2879 can produce 250 watts is accurate, so long as linearity and long term reliability are not factors, and the 250 watts does not have to be "harmonics" or things that mislead power meters (although this could be true in some cases).
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Real world with 13.8 volts, as seen in today's automotive electrical systems, in a better designed test jig I think the result would be higher as well on the 2sc2290. Although i do not agree with the inflated numbers claimed by Amp builder`s in the CB world, do you not agree that the results could be better than 60 watts based on past reading`s/experience?
Please do not fall back on the " knows more about what the 2290 will do than the folks that did the R&D and then the manufacturing of it" Statement and take into account your own experience with 2x2sc2290 amps.

73
Jeff
 
it can do more but with increasing distortion . 13.8 volts can get a little more but not enough to make a difference in talking distance so the only real detectable benefit is making the meter swing further to the right ....... or am i missing something ?
 
BOOTY MONSTER said:
it can do more but with increasing distortion . 13.8 volts can get a little more but not enough to make a difference in talking distance so the only real detectable benefit is making the meter swing further to the right ....... or am i missing something ?
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You have to keep in mind that in the CB world there is no consideration of IMD or anything else that pertains to proper operation of an RF amplifying device or the splatter that results from the improper operation of that device. It is in fact all about how far the meter goes to the right and how bad assed someone can make themselves feel after stomping on someone else.
 
Captain Kilowatt said:
You have to keep in mind that in the CB world there is no consideration of IMD or anything else that pertains to proper operation of an RF amplifying device or the splatter that results from the improper operation of that device. It is in fact all about how far the meter goes to the right and how bad assed someone can make themselves feel after stomping on someone else.
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im happy with the size of my penis , i dont need big swing on a meter or a distorted over modulated signal to make me feel worthy .
 
BOOTY MONSTER said:
it can do more but with increasing distortion . 13.8 volts can get a little more but not enough to make a difference in talking distance so the only real detectable benefit is making the meter swing further to the right ....... or am i missing something ?
Click to expand...


you ain't missing anything Booty,the swinging meter might look pretty but comes at the cost of sounding worse and possibly splattering all over nearby neighbours making you about as popular as a fart in an astronauts suit,not to mention the increased risk of rfi.

It's all about ego and boasting rights as Captain Kilowatt says and nothing to do with good rf operating practice.

It truly is cb bullshit of the highest calibre.
 
AudioShockwav said:
Lets revisit the thread about the 2sc2879 for a minute, I believe it has already been shown by W8JI that the test set up used for the Spec sheet is not optimal, and in fact the 2879 can indeed produce more power than the single limited test jig has shown at 12.5 volts.




Real world with 13.8 volts, as seen in today's automotive electrical systems, in a better designed test jig I think the result would be higher as well on the 2sc2290. Although i do not agree with the inflated numbers claimed by Amp builder`s in the CB world, do you not agree that the results could be better than 60 watts based on past reading`s/experience?
Please do not fall back on the " knows more about what the 2290 will do than the folks that did the R&D and then the manufacturing of it" Statement and take into account your own experience with 2x2sc2290 amps.

73
Jeff
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thanks for trying but i dont think there own experience would be considered here when someone wants to disagree.when reading through many of the threads on here i have noticed that sometimes people will contradict themselves just to disagree with someone.back when i repaired radios and amplifiers i would order transistors from rf parts and i always requested matched transistors from a high power lot.it was not uncommon to get a pair of matched 2sc2879s that came tested at 110-120 watts a piece (toshiba rating 100 watts) it also was not uncommon to get a set in the range of 88-94 watts each.those all came with a test sheet with 4 watts input.i dont think those were cb world high caliber tests but whatever.i have yet to see a 2x2290 that does 120 watts but i guess i am a true cb world idiot oh well.rf parts catalog lists the 2290 at 80 watts and i have seen others rate it at 90 watts but i know this is a one way street.i would be interested in reading those threads he must have took hell for that.
 
i would be interested in reading those threads he must have took hell for that.
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Here is the thread that started it here on this Forum, And Quotes taken from another as well. The Gentleman I quoted is W8JI, he is the "chief designer of amplifiers for Ameritron"


http://www.worldwidedx.com/amplifiers/57320-hundreds-watts-per-amplifier.html

It always gets brought up that , and I quote"
I have seen on the meter where harmonics seem to have increased avg power out put readings.
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Here was His reply:
Two ways a power meter can show an unexplained false high reading of forward power:

1.) When the load is a narrow band resonant load, like a monoband antenna, and the harmonics are at a frequency with a very high SWR.

2.) When the meter has greatly increased sensitivity at increasing frequency.

3.) When the harmonics or a parasitic has a significant percentage of desired signal power.

On a dummy load on the bench with a wide bandwidth meter, I did not have any of those problems. A spectrum analyzer showed the harmonic power was only a few percent of total power.

You are right to not trust CB shootout power claims, but clearly at least one
2SC2879 can produce over 250 real watts over and over again, with 30 seconds or so on time, without damage. :)

It really was not getting that hot with the big heatsink, but I didn't want to ruin my only 2SC2879.
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The point I was trying to make was that everytime it is brought up that a XXXXXX transistor can make XXX watts, someone throws it out there that the Spec sheet says it will only do XX watts.
Tom explained it this way...

It is common for people to think data sheet numbers are all hard limits, but a large amount of the data in sheets is NOT a hard limit.

A Zener diode would be a hard limit for voltage, but not for current or dissipation. The part might actually handle two or three times the rated current or dissipation before failing.

Resistors are the same. The resistance is absolute, but the dissipation or voltage rating (yes, they have voltage limits) is not. A 2 watt metal resistor might stand 5 watts for months or years before failing. A 2 watt resistor, like a carbon comp, might fail in a few thousand hours at 75% percent of rated dissipation. This is why standard resistors make about the worse fuse in the world, but some people think they are fuses that pop open with a modest overload.

Tubes and transistors are no exception. If you look at all the data sheets for the MRF150 you won't find it outputs 600 watts per transistor anywhere, but in pulse service it can. I built a medical device that ran over a kilowatt on two MRF-150's and they last years and years in the field.

A single 3-500Z can output several kW in low duty cycle operation, and can run 150% of rated anode current for years without accelerated failures, but the data sheet doesn't say it can do that.

73 Tom
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During the thread that was on this forum I had agreed with Shockwav that the 2879 would do more than 120 watts, I have seen a 2879 do over 200 watts at 20 volts....there are problems with running the device that hard, if you do not have ALL of your ducks in a row, you will be replacing transistors daily. It is NOT advisable to run them like that for a "Daily driver" But to say it can not be done is sticking ones head in the sand.
I Also do not think a 2sc2290 is limited to 60 watts.... when I have seen them do more, and without sounding like a spark gap generator.

i am sure that a large Quantity of popcorn is going to be needed after I hit the Submit Reply button...

73
Jeff

( Sorry for getting off topic, I did not mean to hijack the thread)
 
BOOTY MONSTER said:
im confused by your statements 1342 . can you better explain what youre saying please ?
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thanks for that read audio that was great.booty your spec sheet rates a 2290 at 60 watts 2x60 would be 120 watts i have seen several 2x2290 amps do between 180 and 250 watts but never 120 watts.as i stated before the toshiba transistors were underrated and i am not the only one that thinks that.i hope this clears things up.maybe my statements are not always clear but it seems often when i reply to someone it spirals off into a whole different topic.
 

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