1.47V On 18 March 2015 at 18:38, James Burkart wrote: > With no input signal, what voltage do you read between the two 4.7 ohm > resistors? > On Mar 18, 2015 12:33 AM, "Ryan O'Connor" wrote: > >> 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 pulldo= wn >> > 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 i= t >> >> runs class B and will distort real bad. >> >> >> >> Also you will need to get the bases of your transistors a little furt= her >> >> 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 play= ing >> >> > 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 remov= e >> >> > 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 playin= g >> >> > 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 ly= ing >> >> > around, or even close to it. I tried a 0.47uF bipolar but I only he= ar >> >> > about 0.05 seconds of audio when I plug/unplug that one. Have doubl= e >> >> > 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 >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > 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 .