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Pop Elimination

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Graydon

New Member
Anyone,

I have built a small Headphone Amp for the purpose of amplifying musical instruments to Headphone Levels. The amp I’ve used is a very small Kit for a 0.5 Watt Amp, and works well. My problem is the big pop when I turn it on or off.

From my limited understanding of electronics, I was under the impression that a Cap of sufficient size would fix this, but the circuit already has a 100uF across the +ve and –ve terminals of the circuit board, and doesn’t seem to do anything.

What I would really like is, to be able to switch it on and have the Volume increase over a period of say 2 seconds until the full volume is reached. (I have a pot that controls this).

Is this possible, and how?

Thanks,
Graydon
 

kinjalgp

Active Member
Pop can be eliminated by delaying the power to power amplifier for few milli-seconds after the main power is swithed on. You said you already have 100uF but this is to small capacitor. Use a large on like 1000uF or 2200uF. I have a pop-eliminating circuit but I'll have to search for it in my old books.
 

Graydon

New Member
Thanks, I tried a 1000uF and 2200 uF Cap, and it certainly seemed to fixed the power Off click by slowly dropping the power, but I still have a problem with the power On Click. Even with the big caps, I get an immediate loud click.

I've attached a pic of the circuit to make things clearer. I replaced the 100uF cap with the 1000uF / 2200uF. How do you use a Cap to slowly turn the power on?

Thanks,
Graydon
 

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