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little gem mk2 amp question? Answered

Hello, i going to make a little gem mk2 amp.But i see 2 layout and they are a bit diffirent ....I dont know what version is correct or both are correct ?? 
And i want to  add a LED to know if the amp is on or off, where should i place it ??? I use a 12v 300mA adapter as power cource.



2 Replies

gmoonBest Answer (author)2011-10-19

A schematic is conceptual--usually concepts like GND and V+ connect by implication, but not explicitly (as is GND is this case). Often (not in this schematic) the IC V+ power supply pins aren't included all, because it's assumed.

On the other hand, a layout or wiring diagram shows the actual physical connections of parts.

Schematics can conveniently avoid considerations such as oscillation from traces or components that should not be in close proximity; layouts cannot.

But schematics are often easier to understand, because the circuits is stripped down to its minimum. If I'm looking to understand a how a circuit works, I want to see the schematic. If I just want to build it, then the layout is preferable.

An LED indicator can be wired directly to the board by placing the LED and a current-limiting resistor (1K? depends on the LED) between a GND and a 9V trace. Or else use a DPDT switch--one pole for the board power, the second pole switches the LED/resistor to the power.

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Re-design (author)2011-10-19

There are several ways this amp can be wired and still work. If you're not sure if a diagram is correct then breadboard it before you make and wire a pc board.

As for the led, wire it so that when you turn on the switch if complete the circuit for the led.  You will have to make arrangements for the correct voltage.

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