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Everything posted by faizanbrohi

  1. well i have done it , i have placed a B50K Rated Potentiometer and it works exceptionally great and there is amazingly no hum , all Working accurately , thanks . I am a happy man now , now i just have to complete the mechanical details of the enclosure i am putting it in . ok thanks again.
  2. Everthing is working fine but there is one problem the Attenuation is still low . i can still hear music when the pot is fully turned off , i think a higher value potentiometer would solve the problem , a 200K or 300K Pot should solve the problem , well i am going to check it in my university because they have big high wattage pots , seems that they should work fine . and one more thing when not playing any sound or music there is a very annoying hum , how to stop this ??
  3. I think there is one problem i need to disconnect the PCB Track , because from the circuit above input and output is not shorted , therefore it is connected by a log potentiometer and not connected directly.
  4. I have a Pot Rated at 50KA x 2 meaning 50K at both ends and A represents that it is LOg i guess , here is a picture of it.
  5. i have a point where the preamp put out a connection between a preamp and power amp where i can implement it ? Can i apply it like this , the first circuit shows the actual volume control circuit.
  6. Hello Audio Guru , i have built the units together in one PCB they are complete . there is only one problem , the speakers are howling because of the microphone. is there any method i can apply to remove it One more thing is that the volume when set to zero . i mean 100Kohm , it is still giving a amplified output at the speaker . i want volume at zero to be implemented where at zero no voice is there at the output what should i do , see the figure i think i should should add a resistor.
  7. How is this circuit for a modified sine wave . see the comparison in the circuit diagram and wave shape. it is zero for some moment as you described in the Diagram
  8. The Power amplifier uses bipolar capacitors , and they were hard to find . why are bipolar capaictors , why not use simple polar capacitors when there is an option. and the input transistors are okay , i have a assembled version of the power amp which i bought as a guide and it is working. no problem with the input tranisitors . Just Hope the amp works . One more thing i tested the assembled version of the power amp with a computer and it ran fine. don't know if it will work with the TL071 Preamp
  9. Can the SG3525 PWM IC Produce a Modified SIne Wave
  10. But the idea is you cannot use pure sinewave in a Inverter , it will heat up the transistors and mosfets very much
  11. I have tested the TL071 opamp preamp it is working great , but the sound when i connect it to the speaker it is really low, i mean it is behaving like a headphone , i think maybe the power amp would increase it .today i will build the Power amp and update you.
  12. Hello everyone . I found a circuit to generate a modified sine wave. Can it be used with the inverter as an oscillator . THe Opamp just filters the modified digital sine wave . so if you dis regard the opamp it gives a approximation sine wave or a modified sine wave , digital sine wave , whatever. Both outputs are shown , with and without op amp
  13. Thanks Audio Guru i think i am making both LM386 one and the TL071 amnd then compare quality .. going to buy parts todays , thanks
  14. IF i only use the Circuit that you have posted in and connect it to my power amp , it will have volume control . but will it have enough power to drive my power amp , and do i have to use the LM386 for that , or just use your TL071. One more thing i have made the PCB's for the LM386 and two transisitor op amp. Now will make for the TL071.
  15. LM386 is also an audio opamp . well the input is from a electret mic , i toook both diagrams from the PDF . Both the documents agree that each of them might be used together. I only want simple volume control and less bulky circuitry , how can i impelmet TL071 in it k17.pdf kit98.pdf
  16. Can you suggest a circuit for the Modified SIne wave inverter
  17. Hello Audio Guru , i have almost built the PCB and refined it , for the 80W Stereo That i posted the first time . i am making only a mono version for the university project. so i also need to make a preamplfier . So i had a preamplfier i made some time , but it had very bad distortion , it was made using a AN7116 Power amplfier IC , had awful distortion. I also tested it with the Power amp . didn't work good for my need. SO here is another schematic . THere is a graph for THD also . I am making a PCB for it . Will this work for my Power Amplfier ?
  18. IF we make a sine wave inverter with making sine wave instead of square wave and and use mosfets in our design 4 parrallel mosfets oen side and 4 parallel mosfets other side, IT willl minimize heat dissipation and we will have a sine wave inverter. BUt making a modified sinewave wave , a digital which has steps in it , would be easier , but will it run a TV or Computer . The UPS I had , if it produces a stepped sine wave , then , i used it to run a computer , full with CRT monitor also and a TV also ran fine .
  19. Well using a modified sine wave won't hurt . What about your sine wave inverter audio guru , that you were making using Texas instruments CLass D Amplfier IC's
  20. But this one is battery dead as well as circuit dead , i used it 4 years back to run television , even a computer , it was known here as a 486 computer UPS You are right i think it is a Modified Sine wave . we can make a modified sine wave and then step up without heating and also can use mosfets. for low heat dissipation
  21. For your Kind Information AUdio Guru , i think XR2206 is being manufactured . It is not yet outdated.
  22. Well amazingly i found a UPS Inverter . and well it is quite complicated , dual layer PCB and all that stuff . i cannot use the parts in it , beacause it is my dad's office UPS and it is dead . so here are some of the things i found . * 4 mosfets IRF240 , 2 sets in parallel . * BUZ11 mosfet * Transformer ( Don't know if it is a ferroresonant Transformer or not ) 5 wires coming out of the input side , one is connected to battery directly. 4 wires coming out from the Input side . * 4 Logic Gates IC , like CD4077 , CD 4093 , TC 4093 and MC14081 * One Quad amp LM339 Now condsidering the following components , i think the Logic gates produce a approximation sine wave and then is filtered into sinewave with a LM339 Quad amp and then Mosfets are used to increase the current , THen THe transformer does the step up .. All in all it is producing a approximation sine wave , i think what do you think ? comment
  23. Okay i will ust test it using the transformer . 24VDC , only testing , after everything is complete i will change it ok
  24. I think about 6 to 7cm toriod but be fine and 20SWG Wire gauge would be adequate , what abou u
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