Hello,

Please refer to the attached schematic for this question. I built the circuit exactly as described in the enclosed schematic and it works great. The only problem is that I need to add a volume control for the speaker output. I was thinking of using a 2n2222 npn transistor as an amplifier and a 5k variable resistor to adjust the sound.
I was hoping you could assist me by posting a schematic with the solution and explaining how your fix works. Thank you for your time with this question.

 

The old fashioned way is to use an L-pad, but 16 ohm L-pads seem a bit difficult to find at a reasonable price. With power levels this low, it seems there must be some other way, starting with, "How much lower do you want the power?".

http://www.ebay.com/itm/Speaker-L-P..._Speaker_Parts_Components&hash=item461128f747

http://www.ebay.com/itm/Mallory-L-1...pt=Vintage_Electronics_R2&hash=item1e838d2c93

 

I was thinking of using a 2n2222 npn transistor as an amplifier and a 5k variable resistor to adjust the sound.

Depending on where it is placed, variable resistors in volume control applications usually call for a logarithmic pot rather than linear type.
Max.

 

Wait. I get it. You intend to use the single ended output option with a coupling capacitor to drive a 2N2222. Right?

Just put an audio taper volume control between the coupling capacitor and the transistor.

 

According to the datasheet page 4, you can use a single output pin on the ic for lower volume, with a dc blocking capacitor in series with your speaker to ground, the ic gives four times the volume using its complimentary +/- pins,so you could use this method..