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70landcruiser
Junior Member
Username: 70landcruiser
Post Number: 17
Registered: 1-2005
| | Posted on Thursday, February 24, 2005 - 10:07 pm: | 
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I just received my Dosy 3001-p meters and hooked them up to see what I got, the swr was 1.1 to 1 and the wattage was 4.5 and swing to 8 on AM then I turned on the amp (20012 x-force base amp) and got 45 deadkey and swing to 90 with amp on low, and 45 deadkey and swing to 150 on high I'm new but that seems really low according to the spec's on this amp? am i doing something wrong! the amp is only a couple weeks old and the pre-amp hasn't worked from day one, when you turn on the pre-amp the signal gets weaker! when you're talking with the amp on you can here the fan pull down is that normal? thanks Doug |
Stickshift
Intermediate Member
Username: Stickshift
Post Number: 192
Registered: 7-2003
| | Posted on Friday, February 25, 2005 - 1:32 am: |
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Sounds like the power supply is too small. I'm not big in the amplifier categorie. Not sure if it's a mobile or base amp. If it's a mobile, start with the power supply and go from there. Someone else on here will surely have more info on this subject.
just trying to help as best as I can |
Audiophile73
Member
Username: Audiophile73
Post Number: 56
Registered: 5-2004
| | Posted on Friday, February 25, 2005 - 2:25 am: |
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well you got a good amp there, the transistors in that amp are the 2sc2879's. Those can take a lot of drive. I do not know what kind of radio you are using but even if it is regular 11 meter mobile it is capable of a 4 watt deadkey swinging to 16. I would just get your dead key up as high as you can and just let is swing. It sounds to me like your modulation isn't opened up. Don't cut the limiter but just open it up all the way. You could deadkey 10 watts into that and probably more. But just call the guys at xforce theyre very good and helpful. I had a 400 mobile that they answered for me. But you just need to drive it harder and youll good power. But let me know how it all turns out. audiophile73@yahoo.com. Mail me if you have any questions |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 483
Registered: 7-2004
| | Posted on Friday, February 25, 2005 - 2:07 pm: |
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the 20012 is a base amp with built in power supply, stickshift. probably provides it's amp with more then 14 volts, too. maybe 17-18.
that power supply should not be allowing the fan to slow down on keyup, cruiser. you should get in touch with them right away. preamp problem was 1st reason to call 'em, low output & high drain on supply are problems 2 & 3.
a 4 watt radio & you should have gone with x200b, with the 2290 driver. the 20012b shouldn't need much dead key to get 125 watts out but a lot of swing in should get a lot out, like 350-400.
if you're only getting 150 on high & the fan slows down, sounds like the power supply isn't working properly. even a texas star 2-2879 swings 250 or better. |
70landcruiser
Junior Member
Username: 70landcruiser
Post Number: 18
Registered: 1-2005
| | Posted on Friday, February 25, 2005 - 10:59 pm: |
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well patzerozero your post is pretty close! I called x-force today and explained what it was doing and they said to send it back! they also said that I'm not driving it nearly hard enough!!hopefully my washington when I get it back(peak+tune)will drive it better!! they said that I should have bought the x200 with a driver! I told thats the one I was advised to buy from one of there outlets! what radio would you recommend that has the high drive, I'm on SSB most of the time... |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 494
Registered: 7-2004
| | Posted on Saturday, February 26, 2005 - 11:54 am: |
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it uses 2-2sc2879 transistors that should handle 7 watts of input each, rms. but that isn't really the right way to go about it. key the radio low & adjust variable til amp is dead keying about 125 watts, it may take 10 watts, it may take less to do it. but the xforce will handle whatever swing the radio can give it, 25-30-more watts of swing, that's where you'll see the amp reach its max on a pep meter, 350-400 give or take. the amp is capable of dead keying more then 125, depending on its built in power supply's limits, maybe as much as 200 watts dead key, but your swing, if it increases at all won't really be much more then it was at 125 watts dead key, so why bother stressing it? if the fans keep it cool, you can try to increase it a bit from the 125 though. remember 14 watts dead key is the max the 2 transistors are rated to handle, so as you approach that output from the radio, you are beginning to stress the 2879's.
if you like the washington, which is a real good radio, see how it does when it comes back. you should make sure it his variable output added. depending on how it's done, it's possible to get REAL 8 watts dead key & 20+ watts swing. even basic peak & tune could get 5+/12+. that's AM, SSB 15+ & up to 22-24 or more is possible.
what is considered 'high-drive' amps are from days long gone, but when EXPORT radios used dual finals to get up to 10 watts dead key & 22 watts pep/SSB, that's what those amps were built to handle. there are still some decent radios out there like that. the connex4800dxl/cobra148fgtldx/rci6900f-25 are still basically 10/22 radios. they have decent receivers & are decent talking radios. lincoln will work but you have to keep an eye on output as it is capable of more. magnums have too much swing & topgun setup itself just overdrives the amps. the original delta force is close to a 10/22 radio & can be made to work with a high drive amp. you have to stay away from the newer 'built-in amp' radios, like the galaxy 48/93/95, rci2970, 6900ftb, new connex, etc.
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70landcruiser
Junior Member
Username: 70landcruiser
Post Number: 19
Registered: 1-2005
| | Posted on Sunday, February 27, 2005 - 11:02 pm: |
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the information your sharing with me is a big help! now if the washington doesn't do the trick what about a rci 2995 turned down to acheve the 125 DK your talking about, and when not using the amp could use the 2995 at whatever power set is needed, or I'm thinking the 2517 with the power set to do same thing, I just wouldn't have the upper power as the 2995 is this correct? the radios your suggesting are moble, I'm think more on the lines of a base unit... thanks again!!! |
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