Recent content by w62820616
  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?
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