The link you posted appears to be for a file that is either private or stored locally so only you can see it. You need to post the link to the project because there is no point asking people to review a PCB without access to the schematic it was created from, including all the symbol data such as pcb footprints, symbol to footprint pin mappings and BOM information. If you are asking about one of the projects in: [https://easyeda.com/Robert37](https://easyeda.com/Robert37)<br> <br> please clearly identify which one you are seeking help for. You should probably read through the comments in this topic and check out the application and PCB layout advice in the other ST datasheets linked to in there before proceeding further: [https://easyeda.com/forum/topic/6-Channel-STA540-Amplifier-PCB-validation-12833f4d561e446a8f14bc4f791c790e](https://easyeda.com/forum/topic/6-Channel-STA540-Amplifier-PCB-validation-12833f4d561e446a8f14bc4f791c790e)<br> <br> If you tidy up the wire ends so that they do not overshoot the pin ends then all those diostracting spurious join dots witl disappear:  You have unconnected pins:  You must connect VCC2 to VCC1. Do not leave the unused signal inputs floating. Tie them to ground through a series RC connection. This will reduce the chances of hum pickup causing unused amps clattering from rail to rail and causing crosstalk problems and excessive hum in the used channels. To ensure that your schematic is suitable for conversion to a PCB please read (4) in (2) in: <u>[https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)</u><br> <br> To ensure that your PCB is suitable for submission to manufacture, please read (6) in (2) in: <u>[https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)</u>

@andyfierman Thanks for the info.  I did read the ST datasheet and other postings on the STA540.  This being my first PCB I am just curious about any feedback on the PCB layout itself. I do not think the unused input pins (IN3/IN4) need to be grounded as they have their own VCC2 connection that is not powered.  There are two separately powered amplifiers in the chip.  I only connect the power supply to VCC1, which powers IN1 and IN2.  The circuit design seems to work fine soldered on perfboard.  But, it's probably a good idea to ground the unused inputs anyway. The project page is here: [https://easyeda.com/Robert37/guitar-amp-v-2](https://easyeda.com/Robert37/guitar-amp-v-2)<br> <br> Robert

After doing additional research, best I can tell is VCC1 and VCC2 are internally connected.   Unclear to me why there are two inputs if they are internally connected, but I will go ahead and connect both to the power supply even though the circuit seems to be working fine with only VCC1 attached to the power supply.

Hi! You can check my schematic on how to draw amplifier schematic more clearly: [https://easyeda.com/markus_jidoka/main-board-sta540](https://easyeda.com/markus_jidoka/main-board-sta540)<br> <br> Regards, Markus Virtanen HW / Electronics Designer

@Markus_ee Thanks.