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  1. w62820616

    Some test results on my pocket amp

    Quote:   Here is another one that already sent to the factory. Simply ground + low impeadence ground buffer. PCB traceguard and improved wiring. Ground plane at back and "clear window" for all the opamps. (Due to the space limitation I remove the current mirror buffer, may consider SMD...
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  3. w62820616

    Some test results on my pocket amp

    Quote: Thanks !!! There are couple things I need to decide before I finalized this project and make a kit. 1. The resistor value between the opamp and the transistor buffer (currently 1k for BJT 400ohm for FET) 2. The resistor value between the output jack and the transistor...
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  6. w62820616

    Question about Eagle CAD PCB layout

    Hello,          I am having trouble to set up an restriction area for OPAMP. I don't want the ground plane to cover the OPAMP socket. Should I use restrict or keepout layer ?   Best Kee
  7. w62820616

    Brush noise from the pot.

    One directly connect to the input jack, one directly connect to the input cap, one directly connect to the ground. Do you think the cap is leaking? I am using WIMA 0.47uf
  8. w62820616

    Brush noise from the pot.

    I noticed that my alps RK097 pot has a noise problem when I turn the shaft really fast. It only happen to the right channel ( where the metal shaft directly connected to). you need a low impedance ear phone to hear the problem (i am using UE ). But if you turn the pot really slow, you will not...
  9. w62820616

    Is it ok to put two 9v battery in parallel?

    I have room for 2 9v batteries and I don't want put them in series ( my gain is only around 5) so 9V is enough. I was thinking maybe i can put them in parallel so that I get double the run time.
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  13. w62820616

    Question about transformer without center tap.

    Quote: Do you know what kind of LED I need to use? Do I need to pair it?  
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  15. w62820616

    Question about transformer without center tap.

    Quote: Thanks ! Do you think 2X 12 VAC @ 584mA (7w) should be enough for normal headphone amplifiers application?
  16. w62820616

    Question about transformer without center tap.

    Quote: Thank you ! So if I want to power my transformer with 110v AC, is what it looks like?  
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    TE2223-CIRCUIT.jpg
  18. w62820616

    CMoy on breadboard problem

    Use the power rail of your breadboard for power for V+ and V-, leave the ground along on one row.
  19. w62820616

    Question about transformer without center tap.

    Hello everyone,                        I found a transformer on digikey which is 10VA, 2X110V primary 2X12V secondary. The schematic is attached below:                   My question is, can I simply combine the two terminals of the output to make a ground?                    Like this...
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    TE2223-CIRCUIT.jpg
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    TE2223-CIRCUIT.jpg
  22. w62820616

    Couple questions about my pocket amp design

    Quote:   Can I just add polygon at both side just to make the board looks nice or it is a bad idea?
  23. w62820616

    Couple questions about my pocket amp design

    Quote: One more question. What I should do about the ground plane?
  24. w62820616

    Couple questions about my pocket amp design

    Quote: The pin of buf634 is only .024.......
  25. w62820616

    Couple questions about my pocket amp design

    Quote: As your command :D, I changed the ground error correction to soic8 so that I can free some space.                
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