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Chipamp IC amp kits & PC boards from ChipAmp

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Old 23rd February 2018, 06:58 PM   #71
scottjoplin is offline scottjoplin  Wales
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Solder the joint you have already made to the "earth" pin on the pot so both the input screen and the white wire to the amp are connected to it
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Old 23rd February 2018, 09:49 PM   #72
Hogwild is offline Hogwild  Canada
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Huh? You lost me. You just told me to remove that green wire from the POT.

How about specifying exactly which wire goes where? I have two white wires, please be more specific.
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Old 23rd February 2018, 09:54 PM   #73
scottjoplin is offline scottjoplin  Wales
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That's right, now connect the screen on the input and the white wire you've soldered it to to the pin on the pot that you removed the green wire from
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Old 24th February 2018, 12:04 AM   #74
Hogwild is offline Hogwild  Canada
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Uh...WHAT? I haven't soldered it to a white wire, I soldered it to the input, nothing else. You've completely lost me.

How about using this format:

X--Y
A-->B

That way, I'll be more likely to understand what you're saying.
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Old 24th February 2018, 12:10 AM   #75
scottjoplin is offline scottjoplin  Wales
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The screen from the source that you've soldered to the white wire with the black negative marking
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Old 24th February 2018, 12:17 AM   #76
Bill_P is offline Bill_P  United States
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Add a wire to connect the RCA jack ground to the pot terminal you labeled 'earth'. Do this for both channels.
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Old 24th February 2018, 12:23 AM   #77
Hogwild is offline Hogwild  Canada
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I'm not using a jack yet. Still in testing phase.
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Old 24th February 2018, 02:48 AM   #78
Hogwild is offline Hogwild  Canada
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D'Oh! Sorry, I think I just figured out what you meant. Will try it tomorrow. Thanks for being patient.

Last edited by Hogwild; 24th February 2018 at 02:58 AM.
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Old 25th February 2018, 06:49 PM   #79
Hogwild is offline Hogwild  Canada
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Well, this is embarrassing. It turns out there was no sound cause I hadn't noticed there was a second set of RCA cables attached to the CD player, and the first set I was using were attached to nothing!

Now that the sound is back, I notice that the advice you all gave me has reduced hum to basically zero. I listened to some music, adjusted the POT and it's effect seems to be very smooth. I put a test CD in the player and played a 100Hz square wave test signal.

Here's what I got. Is something wrong? The waveforms look a little rounded off to me.

DS0017.BMP


DS0018.BMP
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Old 25th February 2018, 11:05 PM   #80
Bill_P is offline Bill_P  United States
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Nothing is wrong - reproducing a low frequency square wave with no discernible tilt requires exceptional low frequency bandwidth. The waveform might look more square at 1kHz. In any case there is nothing wrong with your waveform.

It seems you have solved all the outstanding problems, so put the amplifier in a case and enjoy the music.
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