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Old 04-15-2012, 02:33 PM
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Post Fatboy amps


Do you know how to properly operate a linear with a internal driver 1x4 or a 2x6 with the variable on the front. I've always stayed away from these type amps and I would consider my self a newbie to them.


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Old 04-15-2012, 04:11 PM
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As a general rule any amp with a driver stage is a low drive amp. There is an E-Bay seller that goes by Swedishimpi or something like that, he claims ridiculous drive levels for the Fatboy amps he sells. He even told me he makes a "special" high drive 1x4 amplifier. LOL whatever keep it ya clown.

Anyway, here is a link for another amp company that lists some max imput numbers for various amplifiers. Alot really depends on who built it, and what the bias is. For example a Texas Star 667 like an input dead key of 1-1.75 watts max, and maybe 14-20 watts peak.

http://www.xforceamps.com/category/TNT-35

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Old 04-16-2012, 08:12 AM
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OK thanks for that how about the variable setting on the amp where's do I need to set it do your turn it wide open I know it only controls the driver section

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Old 04-16-2012, 09:54 AM
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next thing you know people are going to be driving 1x4 amps with 150 watts and wondering why they blew their stuff up.
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Old 04-16-2012, 10:35 AM
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2x6 amp
well if the amp has 2sc2879 finals according to the manufacturers spec sheet the pill has 13 db gain. when the sums are done that means that if you put in 1 watt you get out twenty. now suppose we say that 1 2sc2879 does 120 watts pep and in a 2x6 amp 6x120=720pep

so divide that by twenty to get the most driver output gets 36pep now it does not matter how many finals are in the driver section because the output remains at 20:1 ratio no matter the number of pills. so we divide 36 by 20 and we get 1.8wattpep.

that means the amp takes at most 1.8 watts on ssb mode. on am it is advised to never exceed 50 percent duty cycle and most hf radios are rated at 40 per cent duty cycle for am/fm so we divide 1.8wattpep by 10 and multiply it by 4 and we get 0.72 watt deadkey.

1x4 amp
4pills at 120pep gives 480 wattspep
480/20 gives 24 wattspep
24/20 gives 1.2 wattspep
1.2/10*4 gives 0.48 watts deadkey.

any more input power than that will shorten the lifetime of the finals.
one would think that it is better if the variable power is turned to full output as the pot should last longer then because it would not be dissipating as much power as otherwise but i am not altogether sure about that.

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Old 04-16-2012, 10:09 PM
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Well I've always ran straight amps (non 1x4 or 1x2). But you could always get a straight 4 pill Fatboy and drive about 100 watts into it. Like a Galaxy 94HP will do around 120 watts once peak and tuned. I've seen that radio and box together do 900 watts with 13.6 volts into it. That would be a perfect setup. People say Fatboy amps are made to take a beating. No, there not! I personally see the best results driving 2.5 watts dead key into my 2 pill. The guy on Ebay that C91Driver was talking about, has been known to scam people. If you need a Fatboy amp, give Chuck's CB Shop a call at 731-847-9296. He does all of my tech work. He's located in Holladay,TN or about 30 miles east of Jackson,TN Plus if you order a amp through him, he will replace anything that breaks except the pills for free (not 100% sure)

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Old 04-17-2012, 05:08 AM
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I run my Fatboy 1x4 (all 2879s) with its variable wide open (I was told the variable on the amp are problematic if you actually try to use them) and it only takes a little more than a single watt to drive it adequately (IIRC, 1.25 watts in gives me a dead key of around 100 watts out).

I know they made different configurations: all 2290s (not common), a 2290 driving four 2879s, and all 2879s; and that will make them all act different. You definitely need a variable power installed in whatever radio you have.
mackmobile43 and fodendaf like this.

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Old 04-17-2012, 05:15 AM
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Quote:
Originally Posted by The Jerk View Post
I run my Fatboy 1x4 (all 2879s) with its variable wide open (I was told the variable on the amp are problematic if you actually try to use them) and it only takes a little more than a single watt to drive it adequately (IIRC, 1.25 watts in gives me a dead key of around 100 watts out).

I know they made different configurations: all 2290s (not common), a 2290 driving four 2879s, and all 2879s; and that will make them all act different. You definitely need a variable power installed in whatever radio you have.
Absolutely correct.

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