Simple Preamp (THAT / SSM / INA) - Development Diary

[juliusbusch]

You should increase the width of the ground tracks; it makes routing somewhat more difficult, but that's what double-sided is for.

Double?

I noticed Pin 1 of the output connector is connected to audio ground; should be connected to "earth".

In all the datasheets and on the evaluation board of the 1646 pin 1 is always connected to GND. Why is that?

Have you breadboarded the LM3914 circuit? I'm not sure you'll find it satisfactory...

I've used this circuit for other projects. The metering got no integration time or smoothing. You're right, it is quite annoying. I thought about a seperat project, building a VU meter using a arduino / microcontroller.
Any  suggestions?

 

[abbey road d enfer]

Double?

Typically I use 2 to 3 mm width for analog ground.

In all the datasheets and on the evaluation board of the 1646 pin 1 is always connected to GND.

  I don't think so. Check page 3 of http://www.thatcorp.com/datashts/THAT_1606-1646-Demo_Datasheet.pdf

I've used this circuit for other projects. The metering got no integration time or smoothing. You're right, it is quite annoying. I thought about a seperat project, building a VU meter using a arduino / microcontroller.
Any  suggestions?

Yes; I would suggest you forget about this mediocre meter. Then you wouldn't waste time tracing stray currents.