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Cbblackbeard
Intermediate Member
Username: Cbblackbeard

Post Number: 227
Registered: 12-2003


Posted on Thursday, April 30, 2009 - 7:24 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I have a linear which has 2 2290's in it. What should I set my radio's dead key at to drive it? How much amp draw does an amp like this consume?
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Bruce
Senior Member
Username: Bruce

Post Number: 5028
Registered: 9-2003


Posted on Friday, May 01, 2009 - 6:52 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

A pair should require no more that 4 watts for full output.
On 6 since 66
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Hotwire
Senior Member
Username: Hotwire

Post Number: 2758
Registered: 1-2005


Posted on Sunday, May 10, 2009 - 1:25 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

A standard cb such as a cobra 29 is a good match to an amp like that.
Set the radio to dead key no more than 2 watts and swing no more than 20 watts and it will be fine.
Kenny
CEF491
Reading the mail around Indianapolis Indiana!

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Hotwire
Senior Member
Username: Hotwire

Post Number: 2759
Registered: 1-2005


Posted on Sunday, May 10, 2009 - 1:27 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Will need around 20 amps to run...give or take for your setup.
Kenny
CEF491
Reading the mail around Indianapolis Indiana!

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Audiophile73
Intermediate Member
Username: Audiophile73

Post Number: 151
Registered: 5-2004
Posted on Wednesday, May 20, 2009 - 3:34 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Without knowing the circuitry of the amplifier it is difficult to say how much drive you will need. If you don't have the tools to do this I would take it to someone that does. If the amp does in fact have two 2290 transistors, you will probably not see more than 160-200 watts out of this box. So to answer your question, your radio should have a carrier (dead key) of whatever it takes to get a 40-50 watt carrier out of your amp. Feel free to e-mail me with any questions you have.
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Ak3383
Member
Username: Ak3383

Post Number: 50
Registered: 11-2005
Posted on Saturday, June 06, 2009 - 3:34 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

With amps such as the one in question I agree that a stock input of 4-watts AM should work well. I have never had any problems running amps at those input levels. The dead key carrier might be a bit higher than if you run say 1-watt of input but I have had the best audio reports with a good strong carrier and some forward modulation. With the deadkey keeping the carrier higher all my modulation can be heard and not just the peaks of my voice. It keeps my voice/signal at a steady level and produces clean sound.
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Flying_cloud
Junior Member
Username: Flying_cloud

Post Number: 35
Registered: 4-2009


Posted on Sunday, June 07, 2009 - 3:36 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The Amp Draw can be found out by this formula:

V=I/R (Ohms law)

Watts Divided by Volts= Amps
If it is a mobile the standard is 13.8 Volts
If a base in the U.S.A. the standard is 120 Volts nominal
Flying High and Flying Proud!!!!!!!!

CEF# 1028
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Ak3383
Member
Username: Ak3383

Post Number: 54
Registered: 11-2005
Posted on Tuesday, June 09, 2009 - 12:05 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The formula is right when applied to a normal circuit with 100% efficiency but the amp in question sounds like an AB class which is about 60% efficient. Meaning for example it takes 100 watts of power to make 60-watts of RF.
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Bruce
Senior Member
Username: Bruce

Post Number: 5090
Registered: 9-2003


Posted on Tuesday, June 09, 2009 - 2:07 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

2SD1446 ...

EFFICIENCY 55%

SO you would need close to 200 watts about 18 amps for a 100 watt amp
On 6 since 66
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Flying_cloud
Junior Member
Username: Flying_cloud

Post Number: 39
Registered: 4-2009


Posted on Tuesday, June 09, 2009 - 1:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

can you explain the AB class amp???
Flying High and Flying Proud!!!!!!!!

CEF# 1028
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Tech808
Moderator
Username: Tech808

Post Number: 16903
Registered: 8-2002


Posted on Wednesday, June 10, 2009 - 2:07 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Class AB Amplifiers

As the designation suggests, Class AB amplifiers are compromises between Class A and Class B operation. They are biased so plate- or collector-current flows less than 360 degrees, but more than 180 degrees, of each RF cycle. Any bias-point between those limits can be used, which provides a continuous selection-range extending from low-distortion, low-efficiency on one end to higher-distortion, higher-efficiency on the other.

Class AB amplifiers are widely used in SSB linear amplifier applications where low-distortion and high power-efficiency tend to both be very important.

Push-pull Class AB amplifiers are especially attractive in SSB linear amplifier applications, because the greater linearity resulting from having one amplifier or the other always conducting makes it possible to bias push-pull Class AB amplifiers closer to the Class B end of the AB scale where the power-efficiency is higher. Alternatively, push-pull Class AB amplifiers can be biased far enough toward the highly-linear Class A end of the scale to make broadband operation without resonant tank circuits possible in applications where broadband operation or freedom from tuning is more important than power-efficiency.
Lon~Tech808
N9CEF~EN50mk
CEF#0808~CVC#0002


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Mrclean
Intermediate Member
Username: Mrclean

Post Number: 128
Registered: 12-2003
Posted on Sunday, August 02, 2009 - 11:31 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

What brand amp?
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Audiophile73
Intermediate Member
Username: Audiophile73

Post Number: 155
Registered: 5-2004
Posted on Saturday, August 22, 2009 - 12:24 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

This is not a difficult question. Check out the datasheet for a Toshiba 2SC2290 transistor. There you will get a good idea for the output. Keep in mind these specs are for 12V, your car will be running closer to 14V, so you will squeeze a little more out. Two 2290 trans. ( I hate calling them pills ) will do about 160-180 watts. So set your carrier (dead key) to do about 80-90 that will leave you plenty of room for full modulation. Hope this helps. Please do this on a bench with a power supply and a appropriate dummy load. If you have any more questions feel free to contact me.

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