power amplifier DB audio
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ultrasonic™
triac
6 posters
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power amplifier DB audio
Good Day Mga Sis,
Please help me with my power amplifier.When i turn the volume up,output transistor always gets busted,including transistor 2n5551 and resistors.Fuses are okay.May problema po ba ang power supply at ang pre-amp?Thank you all.
Things that i did:
i replace all the resistor,transistor na 2n5551,output transsitor.When i turn the volume up sunog na naman ang resistor at sira na rin yung output transistor.Kung 1/4 lang volume ko di naman masisira yung unit.
Please help me with my power amplifier.When i turn the volume up,output transistor always gets busted,including transistor 2n5551 and resistors.Fuses are okay.May problema po ba ang power supply at ang pre-amp?Thank you all.
Things that i did:
i replace all the resistor,transistor na 2n5551,output transsitor.When i turn the volume up sunog na naman ang resistor at sira na rin yung output transistor.Kung 1/4 lang volume ko di naman masisira yung unit.
triac- 12V BATTERY
- Posts : 792
Join date : 2011-04-28
Re: power amplifier DB audio
pwede siguro sis sira ang spkr.. na try mo na e check baka sobrang mabigat na ang reading (very low resistance almost short).. or minsan naman sumasayad na voice coil...
or else out bias iyan.. kaya nasusunog
or else out bias iyan.. kaya nasusunog
ultrasonic™- 24V BATTERY
- Posts : 4475
Join date : 2010-08-19
Age : 38
Location : Davao City
Re: power amplifier DB audio
sis ultrasonic okay naman po yung speaker..tama ang resistance niya at hindi rin sumasayad ang voice coil niya..check ko po yung biasing na sinasabi mo..thank sa info sir..
triac- 12V BATTERY
- Posts : 792
Join date : 2011-04-28
Re: power amplifier DB audio
@sir danny,sir ano po yung idling at bias current?paano e measure yan sa analog tester?sorry po sir danny baguhan pa lang po ako.salamat.
triac- 12V BATTERY
- Posts : 792
Join date : 2011-04-28
Re: power amplifier DB audio
Getting Bias Current of an Output Transistor of an Amplifier Circuit
In this article, we will be focused on getting the bias current of an output transistor of an amplifier circuit. According to wikipedia:
Biasing in electronics is the method of establishing predetermined voltages or currents at various points of an electronic circuit to set an appropriate operating point. The operating point of a device, also known as bias point, quiescent point, or Q-point, is the steady-state operating condition of an active device (a transistor or vacuum tube) with no input signal applied.
This is the method shared by ricdelros, one of the Elab Forum member, based on the topic about “how to get the bias current of an output transistor” Bias voltage can be simply check by following situations that will serve as a guide.
1. Power-up the amplifier circuit without Output Transistor.
Having a driver transistors can provide a few hundred milliwatts of power without the Output Transistor which should be enough to tell if an amplifier operation is correct. If it’s going right so far, turn of power and connect the output transistors, turn the bias trimmer to max resistance, connect 8 Ohms load and apply power again.
Example: If you have 60w amp, connect a DC Voltmeter across either of Output Emitter Resistor and adjust Bias Trimmer and adjust trimmer for a reading of slightly less than 20mv, this will set an Idle Current of around “50mA” which is close to specs of 60w. Watch your multimeter while testing. If at anytime the reading jumps when you have no input, “”STOP”” and check quickly for circuit oscillation, if you are not lucky, such condition may blow fuse, amplifier with this kind of problem can cause heartburn and lots of ulcer and stress. Recheck the circuits..
2. Another way is to check Both Emitter Resistor voltage of the output transistor. Connect a Positive lead to Point M and a negative lead to Point N and advance the idle by trimmer until you get a voltage reading of 20 millivolts below.
3. Other very simplest way is to connect a Milliammeter between the Power Supply Source and to either Positive or Negative Rail Terminal (must have a firm connection or else a little loose can blow the opposite fuse). You can see the the idle current here of 50mA as registered in step 1. This method is the one we used in testing the idle current taught by our instructor while I’m studying electronics.
ilabas lang natin ito Sir Danny
Source From Elab
Hertz- Admin
- Posts : 1822
Join date : 2010-08-12
Age : 43
Location : Cagayan De Oro City
Re: power amplifier DB audio
@Hertz,thank you po dito sir,+1 po sa iyo.dagdag kaalaman po.
triac- 12V BATTERY
- Posts : 792
Join date : 2011-04-28
Re: power amplifier DB audio
mga sis next week pa ako maka update nito.salamat.
triac- 12V BATTERY
- Posts : 792
Join date : 2011-04-28
Re: power amplifier DB audio
musta ito master triac?
Electro- 24V BATTERY
- Posts : 1488
Join date : 2010-08-26
Age : 35
Location : Calinan Davao City
Re: power amplifier DB audio
update ko lang ito mga sis..okay na po ang unit..
defective parts A940 & C2073 leaky po ito mga sis..at isa pa sa bangongot ko,nakabili ako ng mga transistor na leaky rin pala.Thanks master electro..sir hertz,sir ultra,at sir danny +1 po sa inyong lahat
defective parts A940 & C2073 leaky po ito mga sis..at isa pa sa bangongot ko,nakabili ako ng mga transistor na leaky rin pala.Thanks master electro..sir hertz,sir ultra,at sir danny +1 po sa inyong lahat
triac- 12V BATTERY
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alvinquimbo- 12V BATTERY
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Join date : 2014-03-29
Age : 35
Location : Davao City
Re: power amplifier DB audio
Oy congratz Sis
ultrasonic™- 24V BATTERY
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Age : 38
Location : Davao City
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