| Author |
Message |
    
Steppenwolf
New member
Username: Steppenwolf
Post Number: 1
Registered: 7-2004
| | Posted on Wednesday, July 21, 2004 - 7:15 pm: | 
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Hello
I am running an amp that has 1-2290 driving 4-2879's. I power the amp with an Astron VS70M p.s. The amp is supposed to dead key between 150-225W, when I adjust it so, it draws ~45A from the P.S., when I modulate the current drops to ~25-30A. I connected a deep cycle battery in parrallel and still get the same results. If I set it up to dead key around 80W it draws about 30A and draws more current when I modulate, which is what I expect it to do. The current meter is built into the p.s. Does anyone have any idea whats going on?
Thanks for any info. |
Tech808
Moderator
Username: Tech808
Post Number: 3033
Registered: 8-2002
| | Posted on Wednesday, July 21, 2004 - 11:31 pm: |
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Steppenwolf.
First off, WELCOME TO THE COPPER FORUM!
Sounds like you are using a Texas Star 667 that uses a 1-2SC2290 driving 4-2SC2879's.
With 4 watts input you should be seeing around 500 watts
The Approx. Power Output with 20 watts input / Approx. Max Current is:
650 Watts / Pulling 58 Amps
You should be pulling more Amps to achieve maximum output unless something is wrong with your power supply or Amp.
Hope this helps.
Lon
Tech808 |
Steppenwolf
New member
Username: Steppenwolf
Post Number: 2
Registered: 7-2004
| | Posted on Thursday, July 22, 2004 - 6:01 pm: |
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Hi Lon
Well maybe I am not explaining myself too clearly. My problem is not the output from the amplifier rather it's the backswing on the current meter that is puzzling me. In other words this evening I checked the current going to the amplifier from a battery with an EXTECH 380940 AC/DC Watt Clamp DMM. I got the following readings w/4W from radio, 100W DK = 25A, w/modulation current drops to 18-20A, 175W DK = 35A, w/modulation currents drops to 22-25A. Is it common for the current to drop when I modulate? The amp is a No Name 5LB. I had it checked out by an engineer to verify that the pills are ok, he found one of the combiner xfmr's center tap was floating so he reconnected it to the resistor like the other one was. Manufacturer says I should get ~175-225W DK and 500W+ RMS. |
Tech548
Moderator
Username: Tech548
Post Number: 162
Registered: 5-2004
| | Posted on Friday, July 23, 2004 - 6:24 pm: |
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Steppenwolf
Turn the power down on the radio to around 1.5 watts and let it swing upwards with modulation.
That 2290 is the driver for the 4 2879s. Your radio is the exciter for the single 2290. I think what's happening here is that you are hitting the driver with too much power. I believe that is one of the reasons why you was seeing the amp meter on the supply swing backwards.
As I said earlier, hit the amplifier with a 1.5 watt deadkey and let it swing up from there. If you still see a backswing on your amp meter, my next thought would be that you possibly may have a voltage regulator problem in your power supply itself.
I'd also be curious to know that kind of radio you are using and what modifications have been done to it.
Hang in there my friend. I'm sure you will be getting some other opinions.
Jeff
Tech548 |
Steppenwolf
New member
Username: Steppenwolf
Post Number: 3
Registered: 7-2004
| | Posted on Saturday, July 24, 2004 - 7:56 am: |
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Hi Jeff
The Radio is an RCI2990, Currently pushing ~1.5-1.75W into Amp. I am planning on setting the amp up in my truck to see if I get the same results. An electricsal engineer friend of mine with a masters bellieves the amp is saturating as the voltage is remaining steady. This problem is proving to be quite educational at the least. My next concern will be getting the power supply checked out. Thanks for your input. |
Tech548
Moderator
Username: Tech548
Post Number: 169
Registered: 5-2004
| | Posted on Sunday, July 25, 2004 - 1:54 am: |
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Steppenwolf
As Lonnie said, we're happy to have you with us.
Keep us posted as to the results you get once it's mounted in your mobile. And what, if anything, is found with your power supply. I could have been way off base about that power supply.
Jeff
Tech548 |
