i have a dave made 2x4 amp and when i turn it on output is around 800 watts but after a few minutes it will drop to 500 . has plenty of amperage to run it and it doesnt feel warm at all . what can be causing output drop
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dave made 2x4 problem
- Thread starter danny maxwell
- Start date
Output goes thru meter to a m105c antenna. 3 watts drive swing 13 watts and 7 watts drive swing 20 watts. 14.4 to 15.4 volts from a 100 amp power supply
Toshiba 2879 require 25 amps EACH or total of 150 amps for your 2X4.
you may not have enough PS
Is PS regulated or floating type?
you may not have enough PS
Is PS regulated or floating type?
Dont know how much difference it makes but it is 2 2290's driving 4 2879s. power supply is a switching power supply. it is a power max pm3-100. I turned up voltage on it but after reading up on it last night i found out it is a switching one. i had a digital multi meter on it yesterday and voltage didn't drop below 14.2. what kind of voltage can the amp handle and how much dead key and swing do i need to put in it . gonna see if i can get power supply to stop switching and stay at higher voltage as i can put in it . THANKS FOR THE HELP I REALLY APPRECIATE IT AND LOVE THE FORUM. WILL BE BUYING THE HOUSE A ROUND OF BEERS AS SOON AS I CAN GET A LOADABLE MONEY CARD . YALL ARE AWESOME!!!!!
http://www.cbtricks.com/radios/galaxy/datasheets/transistors/pdf/2sc2290.pdf
http://www.advancedsemiconductor.com/pdf/2sc2879.pdf
2sc2290 are 20 amp current draw at 60 watt output 12v
2sc2879 and 25 amp current draw at 100 watts output 12v
Your switching PS is probably doing all it can do to put 500 output at 14v
If you had a 150 amp PS ( 200 amp PS nice to have head room) you would have consistent output if the amplifier is working correctly.
http://www.advancedsemiconductor.com/pdf/2sc2879.pdf
2sc2290 are 20 amp current draw at 60 watt output 12v
2sc2879 and 25 amp current draw at 100 watts output 12v
Your switching PS is probably doing all it can do to put 500 output at 14v
If you had a 150 amp PS ( 200 amp PS nice to have head room) you would have consistent output if the amplifier is working correctly.
yes sir i was afraid of that . I might try a combination of PS and battery or two if i can get PS to stop switching. Thanks again for you time and help. This website is the best thing for a person like me thats got moreb questions than answers. keep up the great work and god bless you and yours from me and mine.
"switching" power supplies doesn't have anything to do with output voltage settings.
google: "switching power supply vs regulated power supply"
your PS should maintain 14.4 volts (max) @ 100 amps
right but this power max converter is a 3 stage unit . its a battery charger a power supply and a power converter and it has 3 different voltage outputs, 1 for each function. it automatically switches according to its function at the time. it has a trimmer pot inside that raises and lowers output voltage. just my thinking and am probably wrong but if i could stop it from switching and it stay on power supply at a little higher voltage would draw less amperage and if i had a couple of batteries in line it would help with amperage draw. I tried it with PS but it went into battery charger mode and since batteries were fully charged it went into stand-by and cut off output. but i understand what your saying and im sure your right but i cant help but try to make what i already have. THANK YOU VERY MUCH SIR , HAVE A BLESSED DAY
If the power supply voltage isn't dropping and the antenna doesn't have an issue you may have a tuning cap in the amplifier failing. I would retest with a dummy load before digging into it. It could be as simple as a bad coax jumper.
Take a look inside and see if anything that looks crispy, maybe a bad solder job somewhere. If you don't see anything obvious I would start by bypassing the variable power pot to verify it isn't the issue. You can also bypass the relay if you have any doubts about it.
You can make up some test jumpers and test the 2 pill and 4 pill sections independently. This can help you determine if the issue is with the driver or final section.
Then remove and test each cap and resistor in the amp. Replace anything that is questionable. You could replace them all for a few bucks. If you have a good transistor tester now is a good time to test the pills.
It seems a lot of work but its the only way to know the amplifier is right. I have used one of those chargers before. It should have no problem running that amp. An 8 pill will make it fall on its face. If RF is getting into the ps it may cause some issues but as long as it holds voltage you're good.
Take a look inside and see if anything that looks crispy, maybe a bad solder job somewhere. If you don't see anything obvious I would start by bypassing the variable power pot to verify it isn't the issue. You can also bypass the relay if you have any doubts about it.
You can make up some test jumpers and test the 2 pill and 4 pill sections independently. This can help you determine if the issue is with the driver or final section.
Then remove and test each cap and resistor in the amp. Replace anything that is questionable. You could replace them all for a few bucks. If you have a good transistor tester now is a good time to test the pills.
It seems a lot of work but its the only way to know the amplifier is right. I have used one of those chargers before. It should have no problem running that amp. An 8 pill will make it fall on its face. If RF is getting into the ps it may cause some issues but as long as it holds voltage you're good.
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Thanks for the info I'm sure it's all of the above lol. I appreciate the help and will put info to good use. Blessing to you and yours from me and mine