Hi Bob thanks for the reply. I added a couple of 180K pull-down resistors after each output, but it made no difference. Still no audio happening unless I pull the cap out and put it back in after a few seconds. Or I turn off my power supply and I hear audio for a brief moment as the caps drop their voltage. The output I hear is still very distorted. It's a published circuit so I'm expecting it to work as-is. Trying to debug the problem really... On 18 March 2015 at 18:01, Bob Blick wrote: > Actually I take back that thing about the third diode, just the pulldown > resistor should fix things. > > Bob > > On Tue, Mar 17, 2015, at 09:46 PM, Bob Blick wrote: >> Hi Ryan, >> >> The LM358 will require a pulldown resistor on its output, otherwise it >> runs class B and will distort real bad. >> >> Also you will need to get the bases of your transistors a little further >> than 2 diodes apart. Put a third diode in there, and it should sound >> great but use too much current. Make that third diode a Schottky and you >> should be golden. >> >> Cheerful regards, Bob >> >> On Tue, Mar 17, 2015, at 09:36 PM, Ryan O'Connor wrote: >> > Hi guys, I've bread-boarded the following circuit, but its not playing >> > audio. I get only DC current at the base of the 2N4401. I've had it >> > playing audio briefly while screwing around. For example if I remove >> > the 0.01uF cap from the non-inverting input of the left-most opamp and >> > plug it back in, I hear a distorted version of the song I am playing >> > as input for about half a second (actually the cap value is polar >> > 47uF). Then silence, DC voltage. Could it be because I am using >> > electrolytics for these two caps? I can't find any "103" bipolar lying >> > around, or even close to it. I tried a 0.47uF bipolar but I only hear >> > about 0.05 seconds of audio when I plug/unplug that one. Have double >> > checked all the wiring twice. >> > >> > Circuit below: >> > >> > http://www.techlib.com/electronics/graphics/audioa14.gif >> > >> > Cheers, >> > Ryan > > -- > http://www.fastmail.com - Choose from over 50 domains or use your own > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .